180 results on '"Shashank Priya"'
Search Results
2. 'One-key-reset' recycling of whole perovskite solar cell
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Dong Yang, Xiaowen Hu, Xiao-Fang Jiang, Xu Huang, Jungjin Yoon, Congcong Wu, Tao Ye, Kai Wang, Shashank Priya, Yuchen Hou, and Guofu Zhou
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Materials science ,business.industry ,Photovoltaic system ,Energy conversion efficiency ,Perovskite solar cell ,General Materials Science ,Raw material ,Cost of electricity by source ,Tin oxide ,Process engineering ,business ,Perovskite (structure) ,Indium tin oxide - Abstract
Summary Sustainably recycling photovoltaic (PV) products at the end of their life cycle is essential for reducing environmental impact and saving costs on raw materials. Halide perovskite PVs currently suffer from a short lifespan, and recycling and remaking could equivalently extend their life cycle. Here, we report an effective and rapid “one-key reset” recycling paradigm to collect all the functional layer components from a used PV device at a high material extraction efficiency. A remade device incorporating all the layers, including recycled indium tin oxide/tin oxide substrate, perovskite, spiro-OMeTAD, and gold, exhibits an average power conversion efficiency of over 20%. This finding that the recycled device exhibits identical performance compared with the original, while providing enormous savings in cost, time, and energy, could lead to a recycling route that will dramatically lower the levelized cost of energy of perovskite PVs and enhance their competitiveness in future energy markets.
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- 2021
3. High-Power Magnetoelectric Voltage Tunable Inductors
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Xiaotian Li, Hairui Liu, Rammohan Sriramdas, Shashank Priya, Cong Tu, Lujie Zhang, Mohan Sanghadasa, Liwei D. Geng, Khai D. T. Ngo, Yu U. Wang, and Yongke Yan
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Materials science ,business.industry ,020208 electrical & electronic engineering ,Magnetoelectric effect ,02 engineering and technology ,Inductor ,Ferrite core ,Magnetic flux ,Inductance ,Control and Systems Engineering ,Saturation current ,Power electronics ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Voltage - Abstract
Magnetoelectric voltage tunable inductors (VTIs) offer a new paradigm for power electronics circuit design. Here, air-gapped VTIs are demonstrated exhibiting a large inductance tunability of 220% with applied fields under 20 kVcm−1 and operational stability up to 5 MHz that covers the full frequency range of the state-of-the-art power electronics. The design of air-gapped VTI comprises of two C-shaped ferrite cores, one permeability-variable magnetic flux valve (MFV) in between C-shaped cores, and slotted air gap between cores and MFV. The tunability of VTIs is achieved through the electric field modulation of permeability in the MFV based on the magnetoelectric effect. There is a tradeoff between the tunability and saturation current. The introduction of air gap significantly reduces the tunability but provides methodology toward increasing the saturation current and power handling capability due to the increased reluctance. The inductance and tunability reduces by 50% with increase in the air-gap width from 0.07 mm to infinity (condition with no C-shaped cores). Phase field simulations demonstrate that the air gap affects the magnetization, permeability, and tunability of VTIs by tailoring the demagnetization field that further influences the magnetic domain rotation process. VTIs with increased frequency range and saturation current will strengthen the continued development of tunable power electronics.
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- 2021
4. Enhanced pyroelectric response from domain-engineered lead-free (K0.5Bi0.5TiO3-BaTiO3)-Na0.5Bi0.5TiO3 ferroelectric ceramics
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Atul Thakre, Jungho Ryu, Kyung Hoon Cho, Do Yoen Kim, Shashank Priya, Yunseok Kim, Il Ryeol Yoo, Panithan Sriboriboon, Hyun Cheol Song, and Deepam Maurya
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010302 applied physics ,Materials science ,business.industry ,Ferroelectric ceramics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Pyroelectricity ,Grain growth ,Tetragonal crystal system ,visual_art ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Optoelectronics ,Antiferroelectricity ,Figure of merit ,Ceramic ,0210 nano-technology ,business - Abstract
Enhanced pyroelectric response is achieved via domain engineering from [001] grain-oriented, tetragonal-phase, lead-free 0.2(2/3K0.5Bi0.5TiO3-1/3BaTiO3)-0.8Na0.5Bi0.5TiO3 (KBT-BT-NBT) ceramics prepared by a templated grain growth method. The [001] crystallographic orientation leads to large polarization in tetragonal symmetry; therefore, texturing along this direction is employed to enhance the pyroelectricity. X-ray diffraction analysis revealed a Lotgering factor (degree of texturing) of 93 % along the [001] crystallographic direction. The textured KBT-BT-NBT lead-free ceramics showed comparable pyroelectric figures of merit to those of lead-based ferroelectric materials at room temperature (RT). In addition to the enhanced pyroelectric response at RT, an enormous enhancement in the pyroelectric response (from 1750 to 90,900 μC m−2 K−1) was achieved at the depolarization temperature because of the sharp ferroelectric to antiferroelectric phase transition owing to coherent 180° domain switching. These results will motivate the development of a wide range of lead-free pyroelectric devices, such as thermal sensors and infra-red detectors.
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- 2021
5. Bio-inspired strategies for next-generation perovskite solar mobile power sources
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Dong Yang, Mohan Sanghadasa, Tao Ye, Abbey Marie Knoepfel, Kai Wang, Luyao Zheng, Jungjin Yoon, Shashank Priya, Yuchen Hou, and Neela H. Yennawar
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Titanium ,Flexibility (engineering) ,business.industry ,Photovoltaic system ,Oxides ,General Chemistry ,Calcium Compounds ,Power (physics) ,Form factor (design) ,Software portability ,Electric Power Supplies ,Photovoltaics ,Solar Energy ,Systems engineering ,Humans ,Electronics ,business ,Perovskite (structure) - Abstract
Smart electronic devices are becoming ubiquitous due to many appealing attributes including portability, long operational time, rechargeability and compatibility with the user-desired form factor. Integration of mobile power sources (MPS) based on photovoltaic technologies with smart electronics will continue to drive improved sustainability and independence. With high efficiency, low cost, flexibility and lightweight features, halide perovskite photovoltaics have become promising candidates for MPS. Realization of these photovoltaic MPS (PV-MPS) with unconventionally extraordinary attributes requires new ‘out-of-box’ designs. Natural materials have provided promising designing solutions to engineer properties under a broad range of boundary conditions, ranging from molecules, proteins, cells, tissues, apparatus to systems in animals, plants, and humans optimized through billions of years of evolution. Applying bio-inspired strategies in PV-MPS could be biomolecular modification on crystallization at the atomic/meso-scale, bio-structural duplication at the device/system level and bio-mimicking at the functional level to render efficient charge delivery, energy transport/utilization, as well as stronger resistance against environmental stimuli (e.g., self-healing and self-cleaning). In this review, we discuss the bio-inspired/-mimetic structures, experimental models, and working principles, with the goal of revealing physics and bio-microstructures relevant for PV-MPS. Here the emphasis is on identifying the strategies and material designs towards improvement of the performance of emerging halide perovskite PVs and strategizing their bridge to future MPS.
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- 2021
6. High‐Efficiency Perovskite Solar Cells with Imidazolium‐Based Ionic Liquid for Surface Passivation and Charge Transport
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Zhuo Xu, Xuejie Zhu, Shengnan Zuo, Cong Zhang, Chenyu Wang, Shengzhong Frank Liu, Dong Yang, Xiaodong Ren, Hui Wang, Wang Likun, Ziyu Wang, Du Minyong, Jiangshan Feng, and Shashank Priya
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Materials science ,Passivation ,010405 organic chemistry ,business.industry ,Perovskite solar cell ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Ion ,chemistry.chemical_compound ,Solar cell efficiency ,chemistry ,Chemical engineering ,Photovoltaics ,Hexafluorophosphate ,Ionic liquid ,business ,Perovskite (structure) - Abstract
Surface defects have been a key constraint for perovskite photovoltaics. Herein, 1,3-dimethyl-3-imidazolium hexafluorophosphate (DMIMPF6 ) ionic liquid (IL) is adopted to passivate the surface of a formamidinium-cesium lead iodide perovskite (Cs0.08 FA0.92 PbI3 ) and also reduce the energy barrier between the perovskite and hole transport layer. Theoretical simulations and experimental results demonstrate that Pb-cluster and Pb-I antisite defects can be effectively passivated by [DMIM]+ bonding with the Pb2+ ion on the perovskite surface, leading to significantly suppressed non-radiative recombination. As a result, the solar cell efficiency was increased to 23.25 % from 21.09 %. Meanwhile, the DMIMPF6 -treated perovskite device demonstrated long-term stability because the hydrophobic DMIMPF6 layer blocked moisture permeation.
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- 2020
7. Tunable High-Power Multilayer Piezoelectric Transformer
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Shashank Priya, Xiaotian Li, Mohan Sanghadasa, Alfredo Vazquez Carazo, and Deepam Maurya
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Frequency response ,Liquid-crystal display ,Materials science ,business.industry ,Electrical engineering ,Converters ,Backlight ,law.invention ,Control and Systems Engineering ,law ,Output impedance ,Electrical and Electronic Engineering ,Transformer ,business ,Electrical impedance ,Voltage - Abstract
Piezoelectric transformers (PTs) have been conventionally used in step-up high-voltage low-power applications such as liquid crystal display (LCD) backlighting for portable electronic devices. PTs have also been considered for step-down applications such as battery chargers for portable devices. In these applications, adapting the output impedance of the PT to meet the requirements of lower output voltages and higher output currents implies the design of PTs with larger number of output layers. Furthermore, these step-down applications require efficient operation of PT under a variety of output load conditions to meet the conditions of battery charging. Thus, strategies to adapt the PT to the variation of the output load are being pursued. In this article, a novel tunable piezoelectric transformer (TPT) for ac–dc and dc–dc high-power converters is presented. This TPT is designed to operate in the radial mode and is fabricated using cofired multilayer process. By introducing control layers into the design, the TPT is shown to provide desired features that include adjustable frequency response and flexible transfer ratio. Fabricated TPT exhibits high efficiency over 96% with an output power capability of 40 W when operating under its nominal load conditions.
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- 2020
8. Decoupled phononic-electronic transport in multi-phase n-type half-Heusler nanocomposites enabling efficient high temperature power generation
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Amin Nozariasbmarz, Shashank Priya, Han Byul Kang, Jean J. Heremans, Bed Poudel, Udara Saparamadu, Wenjie Li, Min Gyu Kang, Adbhut Gupta, and Heon Joong Lee
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Nanocomposite ,Materials science ,business.industry ,Mechanical Engineering ,Energy conversion efficiency ,chemistry.chemical_element ,02 engineering and technology ,Tungsten ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,0104 chemical sciences ,chemistry ,Mechanics of Materials ,Electrical resistivity and conductivity ,Seebeck coefficient ,Thermoelectric effect ,Optoelectronics ,Figure of merit ,General Materials Science ,0210 nano-technology ,business - Abstract
Strongly coupled electronic and thermal transport behavior in thermoelectric (TE) materials has limited their figure of merit (zT). Here we provide breakthrough in decoupling TE parameters in n-type (Hf0.6Zr0.4)NiSn0.99Sb0.01 half-Heusler (hH) alloys through multi-scale nanocomposite architecture comprising of tungsten nanoinclusions. The tungsten nanoparticles not only assist electron injection, thereby improving electrical conductivity, but also enhance the Seebeck coefficient through energy filtering effect. The microstructure comprises of disordered phases with varying size of microstructural features, which assists in effective scattering of heat-carrying phonons over diverse mean-free-path ranges. Cumulatively, these effects are shown to result in outstanding thermoelectric performance of zTmax ∼ 1.4 at 773 K and zTavg ∼ 0.93 between 300 and 973 K. Using this material, a TE generator is demonstrated, which exhibits high power density of 13.93 W cm−2 and conversion efficiency of 10.7% under ΔT = 674 K. The fundamental material design principle for TE nanocomposites demonstrated here can be generalized and extended to other TE systems.
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- 2020
9. High-Performance Thermoelectric Generators for Field Deployments
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Bed Poudel, Ravi Anant Kishore, Amin Nozariasbmarz, and Shashank Priya
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Materials science ,business.industry ,Thermal resistance ,Energy conversion efficiency ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,01 natural sciences ,Automotive engineering ,0104 chemical sciences ,Waste heat recovery unit ,Thermoelectric generator ,General Materials Science ,0210 nano-technology ,business ,Energy harvesting ,Thermal energy ,Power density - Abstract
Thermoelectric power generation is a reliable energy harvesting technique for directly converting heat into electricity. Recent studies have reported the thermal-to-electrical energy conversion efficiency of thermoelectric generators (TEGs) up to 11% under laboratory settings. However, the practical efficiency of TEGs deployed under real environments is still not more than a few percent. In this study, we provide fundamental insight on the operation of TEGs in realistic environments by illustrating the combinatory effect of thermoelectric material properties, device boundary conditions, and environmental thermal resistivity on TEG performance in conjunction with the module parameters. Using numerical and experimental studies, we demonstrate the existence of a critical heat transfer coefficient that dramatically affects the design and performance of TEGs. Results provide a set of concrete design criteria for developing efficient TEGs that meet the metrics for field deployments. High-performance TEGs demonstrated in this study generated up to 28% higher power and 162% higher power per unit mass of thermoelectric materials as compared to the commercial module deployed for low-grade waste heat recovery. This advancement in understanding the TEG operation will have a transformative impact on the development of scalable thermal energy harvesters and in realizing their practical targets for efficiency, power density, and total output power.
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- 2020
10. Maximizing power generation from ambient stray magnetic fields around smart infrastructures enabling self-powered wireless devices
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Shashank Priya, Hyeon Lee, Prashant Kumar, Min Gyu Kang, Rammohan Sriramdas, and Mohan Sanghadasa
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Renewable Energy, Sustainability and the Environment ,business.industry ,Computer science ,Electric potential energy ,Electrical engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,0104 chemical sciences ,law.invention ,Power (physics) ,Generator (circuit theory) ,Capacitor ,Electricity generation ,Nuclear Energy and Engineering ,law ,Environmental Chemistry ,Energy transformation ,Wireless ,Electricity ,0210 nano-technology ,business - Abstract
Harvesting electrical energy from stray magnetic fields is appealing for development of a sustainable power source for Internet of Things (IoT) devices that are being implemented in the smart infrastructure. Stray magnetic fields are ubiquitous in buildings, but have fixed frequency (50/60 Hz) and low amplitude. Magnetoelectric (ME) coupled magneto-mechano-electric (MME) energy conversion is the most efficient way to convert these low frequency stray magnetic fields into electricity. However, currently reported ME coupled MME generators produce high output power only under relatively strong magnetic fields (≥500 μT), which are not available under practical conditions. Here a novel ME coupled MME generator has been demonstrated that provides 400% higher output power compared to the state-of-the-art, when operating below magnetic field levels of 100 μT. The optimized ME coupled MME generator produces milliwatt power below 300 μT stray magnetic field. The output power from extremely low magnetic fields (≤50 μT) is sufficient to power hundreds of light emitting diode (LED) arrays and operate a digital clock without charging a capacitor. By exploiting the harvested power near a home appliance, sustainable powering of sensors and a wireless communication system is demonstrated. Fundamental advancements from this work will provide a direction for deploying ME and MME generator driven self-powered IoT devices in smart infrastructures.
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- 2020
11. High Power Density Body Heat Energy Harvesting
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Wenjie Li, Ricardo Cruz, Ravi Anant Kishore, Amin Nozariasbmarz, Shashank Priya, Udara Saparamadu, and Bed Poudel
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Materials science ,business.industry ,Contact resistance ,Wearable computer ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,01 natural sciences ,Automotive engineering ,0104 chemical sciences ,Thermoelectric generator ,General Materials Science ,Electricity ,0210 nano-technology ,business ,Energy harvesting ,Wearable technology ,Power density - Abstract
Thermoelectric generators (TEGs) can convert body heat into electricity, thereby providing a continuous power source for wearable and implantable devices. For wearables, the low fill factor (area occupied by legs over the TEG base area) TEG modules are relevant as they provide large thermal gradient across the legs and require less material, which reduces the cost and weight. However, TEGs with a fill factor below 15% suffer from reduced mechanical robustness; consequently, commercial modules are usually fabricated with a fill factor in the range of 25-50%. In this study, TEG modules with a low and high fill factor are demonstrated and their performance is compared in harvesting body heat. Fabricated modules demonstrate ∼80% output power enhancement as compared to commercially available designs, resulting in high power density of up to 35 μW/cm2 in a steady state. This enhanced power is achieved by using two-third less thermoelectric materials in comparison to commercial modules. These results will advance the ongoing development of wearable devices by providing a consistent high specific power density source.
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- 2019
12. Nonionic Sc3N@C80 Dopant for Efficient and Stable Halide Perovskite Photovoltaics
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Shashank Priya, Dong Yang, Xiao-Fang Jiang, Congcong Wu, Kai Wang, James C. Duchamp, Rong Huang, Xiaowen Hu, Harry C. Dorn, and Xiaoyang Liu
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Materials science ,Dopant ,Renewable Energy, Sustainability and the Environment ,business.industry ,Schottky barrier ,Energy Engineering and Power Technology ,Halide ,Ionic bonding ,02 engineering and technology ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Fuel Technology ,Chemical engineering ,Chemistry (miscellaneous) ,Photovoltaics ,Electrical resistivity and conductivity ,Materials Chemistry ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
One major challenge in the commercialization of halide perovskite solar cells is the device instability against moisture. Efficient perovskite solar cells usually incorporate the ionic dopants within the charge transfer material to secure their electrical conductivity. Typical ionic dopants are hygroscopic, resulting in significant moisture adsorption and accelerated perovskite degradation. Herein, we report a nonionic dopant, Sc3N@C80, consisting of a hydrophobic fullerene cage that encapsulates the metal salt to achieve a moisture resistive and highly electrically conductive hole transfer layer (HTL). The direct electronic transaction between Sc3N@C80 and spiro-OMeTAD renders a drastically improved conductivity and a lower Fermi-level of the HTL to minimize the Schottky barrier. The hydrophobicity of Sc3N@C80 also decreases the moisture wettability. Perovskite solar cells using the Sc3N@C80-doped HTL exhibit an efficiency surge from 18.15 to 20.77% (champion cell exhibiting 21.09%) and improved device s...
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- 2019
13. Mono-crystalline Perovskite Photovoltaics toward Ultrahigh Efficiency?
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Joseph G. Shapter, Congcong Wu, Dong Yang, Kai Wang, and Shashank Priya
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Virginia tech ,Engineering ,business.industry ,Multiple quantum ,Semiconductor materials ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Assistant professor ,0104 chemical sciences ,Management ,General Energy ,Photovoltaics ,0210 nano-technology ,business ,Associate professor ,Vice president ,Graduation - Abstract
Dr. Kai Wang joined CEHMS, Virginia Tech as a Postdoctoral Associate in 2017 after his graduation from The University of Akron. In the fall of 2018, Kai joined Pennsylvania State University as a Research Assistant Professor in the College of Earth and Mineral Sciences, Department of Materials Science and Engineering. His research interests include halide perovskite photovoltaics, two-dimensional multiple quantum well physics, and bioelectronics. Dr. Shashank Priya currently serves as the Associate Vice President for Research and Director, Strategic Initiatives at Pennsylvania State University. He is a professor in the Department of Materials Science and Engineering at Pennsylvania State University and Adjunct Professor in the Department of Mechanical Engineering at Virginia Tech. Priya's research focuses on the intersection of multifunctional materials, bio-inspired systems and technologies, and energy harvesting and storage. As the principal investigator, he leads multiple programs targeting the development of thermoelectrics, photovoltaics, piezoelectrics, and other emerging energy-conversion and storage devices. Dr. Dong Yang worked with Professor Shengzhong (Frank) Liu in Shaanxi Normal University, China since 2014 and became a full professor in 2017. Dong joined Virginia Tech in 2017 and moved to Pennsylvania State University in the fall of 2018 as Research Assistant Professor. His research interests include solar cells, semiconductor materials, materials science, and engineering of graphene carbon materials. Dr. Congcong Wu has led the solar cell team in CEHMS, Virginia Tech since 2014. In the fall of 2018, Congcong joined Pennsylvania State University as Research Associate Professor. His research mainly focuses on developing next-generation photovoltaic systems for clean and efficient energy conversion. Dr. Joe Shapter received his PhD in Reaction Dynamics from the University of Toronto in 1990. He subsequently held an NSERC Fellowship at The University of Western Ontario before moving to Australia in 1996 to take up a position at Flinders University. Joe served as Dean of the School of Chemical and Physical Sciences for 6.5 years and headed the Flinders involvement in both the Australian Microscopy and Microanalysis Research Facility (AMMRF) and the Australian National Fabrication Facility (ANFF), and was SA Director for AMMRF. His major interests are in the area of novel nanomaterial production, nanometer-scale characterization of these materials, and their applications in, for example, sensors or solar cells.
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- 2019
14. Recent Advances in Flexible Perovskite Solar Cells: Fabrication and Applications
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Dong Yang, Shengzhong Frank Liu, Ruixia Yang, and Shashank Priya
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Electron mobility ,Materials science ,Fabrication ,010405 organic chemistry ,Band gap ,business.industry ,Reviews ,Nanotechnology ,General Chemistry ,Review ,010402 general chemistry ,01 natural sciences ,perovskite solar cells ,Catalysis ,Flexible electronics ,0104 chemical sciences ,photovoltaics ,Vacuum deposition ,Photovoltaics ,Electronics ,vacuum deposition ,business ,Flexible Electronics ,Perovskite (structure) - Abstract
Flexible perovskite solar cells have attracted widespread research effort because of their potential in portable electronics. The efficiency has exceeded 18 % owing to the high‐quality perovskite film achieved by various low‐temperature fabrication methods and matching of the interface and electrode materials. This Review focuses on recent progress in flexible perovskite solar cells concerning low‐temperature fabrication methods to improve the properties of perovskite films, such as full coverage, uniform morphology, and good crystallinity; demonstrated interface layers used in flexible perovskite solar cells, considering key figures‐of‐merit such as high transmittance, high carrier mobility, suitable band gap, and easy fabrication via low‐temperature methods; flexible transparent electrode materials developed to enhance the mechanical stability of the devices; mechanical and long‐term environmental stability; an outlook of flexible perovskite solar cells in portable electronic devices; and perspectives of commercialization for flexible perovskite solar cells based on cost.
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- 2019
15. Monocrystalline perovskite wafers/thin films for photovoltaic and transistor applications
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Congcong Wu, Dong Yang, Shashank Priya, Kai Wang, and Yuchen Hou
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Materials science ,Silicon ,Renewable Energy, Sustainability and the Environment ,business.industry ,Transistor ,Photovoltaic system ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Engineering physics ,law.invention ,Monocrystalline silicon ,chemistry ,law ,Photovoltaics ,General Materials Science ,Wafer ,Thin film ,0210 nano-technology ,business ,Diode - Abstract
High-purity monocrystalline silicon has a long history in the development of photovoltaics; so far, it has dominant applications in modern computers with its profound implementations in transistors and chips. The success of silicon has shown that monocrystalline wafers/thin films of semiconducting materials with superior electronic properties are a good platform for optoelectronic and electronic applications. Recently, the newly emerging semiconducting materials of halide perovskites (HPs) have attracted considerable attention owing to their continuing success in high-efficiency solar cells. The demonstrated optoelectronic properties of HPs indicate that it could be a promising alternative to the silicon-based semiconducting industry. However, the prerequisite of high-efficiency devices is the material accessibility of monocrystalline HPs (mono-HPs), as per the lessons learned from monocrystalline silicon. Current HPs-based technologies, in terms of research areas such as solar cells, photodetectors, light-emitting diodes (LEDs), lasers, and transistors, suffer a bottleneck in manufacturing mono-HP wafers/thin-film materials; hence, exciting results involving mono-HP devices are absent. State-of-the-art optoelectronic HP-based devices are exclusively built using polycrystalline thin films, which are limited in their performance due to issues such as grain-boundary defects, large trap density, and inhomogeneous charge transport. However, these issues can be resolved by utilizing mono-HPs. In this review, we provide in-depth analyses and discussions on the potential of mono-HPs in photovoltaics and transistor applications, and we present the remaining challenges, as well as promising research strategies, to provide a direction for future programs.
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- 2019
16. Energy scavenging from ultra-low temperature gradients
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Brenton Davis, Mohan Sanghadasa, Ravi Anant Kishore, Han Byul Kang, Austin Hannon, Amin Nozariasbmarz, David Emery Kennedy, Shashank Priya, Min Gyu Kang, Jake Greathouse, Alec Millar, and Daniel Mittel
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Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,Global warming ,02 engineering and technology ,Thermomagnetic convection ,Heat sink ,021001 nanoscience & nanotechnology ,Pollution ,Engineering physics ,Renewable energy ,Nuclear Energy and Engineering ,Waste heat ,0202 electrical engineering, electronic engineering, information engineering ,Environmental Chemistry ,Environmental science ,Electricity ,0210 nano-technology ,business ,Energy harvesting ,Power density - Abstract
Thermal energy harvesting from natural resources and waste heat is becoming critical due to ever-increasing environmental concerns. However, so far, available thermal energy harvesting technologies have only been able to generate electricity from large temperature gradients. Here, we report a fundamental breakthrough in low-grade thermal energy harvesting and demonstrate a device based on the thermomagnetic effect that uses ambient conditions as the heat sink and operates from a heat source at temperatures as low as 24 °C. This concept can convert temperature gradients as low as 2 °C into electricity while operating near room temperature. The device is found to exhibit a power density (power per unit volume of active material) of 105 μW cm−3 at a temperature difference of 2 °C, which increases to 465 μW cm−3 at a temperature difference of 10 °C. The power density increases by 2.5 times in the presence of wind with a speed of 2.0 m s−1. This advancement in thermal energy harvesting technology will have a transformative effect on renewable energy generation and in reducing global warming.
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- 2019
17. Energy harvesting and strain sensing in smart tire for next generation autonomous vehicles
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Vireshwar Kumar, Hyun Cheol Song, Deepam Maurya, Prashant Kumar, Rammohan Sriramdas, Ravi Anant Kishore, Min Gyu Kang, Seyedmeysam Khaleghian, Saied Taheri, Jung-Min Park, and Shashank Priya
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ComputingMilieux_THECOMPUTINGPROFESSION ,Computer science ,Piezoelectric sensor ,business.industry ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,Management, Monitoring, Policy and Law ,021001 nanoscience & nanotechnology ,Frame rate ,7. Clean energy ,Automotive engineering ,Power (physics) ,General Energy ,Electricity generation ,Control system ,0202 electrical engineering, electronic engineering, information engineering ,Wireless ,0210 nano-technology ,business ,Energy harvesting ,Efficient energy use - Abstract
We demonstrate the feasibility of the strain energy harvesting from the automobile tires, powering wireless data transfer with enhanced frame rates, and self-powered strain sensing. For this, we used a flexible organic piezoelectric material for continuous power generation and monitoring of the variable strain experienced by a tire under different driving conditions. Power output of ∼580 µW at 16 Hz (∼112 km/h) from the energy-harvester and mounted on a section of a tire, is sufficient to power 78 LEDs. We further demonstrate that the stored energy was sufficient to power the wireless system that transmits tire deformation data with an enhanced frame rate to control system of a vehicle. Using sensors mounted on a tire of a mobile test rig, measurements were conducted on different terrains with varying normal loads and speeds to quantify the sensitivity and self-powered sensing operation. These results provide a foundation for self-powered real-time sensing and energy efficient data transfer in autonomous vehicles.
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- 2018
18. 22% Efficiency Inverted Perovskite Photovoltaic Cell Using Cation‐Doped Brookite TiO2 Top Buffer
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Kai Wang, Sen Zhang, Xiaowen Hu, Xiao-Fang Jiang, Guofu Zhou, Colton Sheehan, Chang Liu, Juan Garcia, Lingling Shui, Shashank Priya, and Zhiyong Zhang
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Fullerene ,Materials science ,General Chemical Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Buffer (optical fiber) ,law.invention ,law ,General Materials Science ,lcsh:Science ,Perovskite (structure) ,Brookite ,business.industry ,inverted perovskite solar cells ,Photovoltaic system ,Doping ,General Engineering ,021001 nanoscience & nanotechnology ,Cathode ,0104 chemical sciences ,high efficiency ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,durability ,Nanorod ,lcsh:Q ,interface engineering ,0210 nano-technology ,business - Abstract
Simultaneously achieving high efficiency and high durability in perovskite solar cells is a critical step toward the commercialization of this technology. Inverted perovskite photovoltaic (IP‐PV) cells incorporating robust and low levelized‐cost‐of‐energy (LCOE) buffer layers are supposed to be a promising solution to this target. However, insufficient inventory of materials for back‐electrode buffers substantially limits the development of IP‐PV. Herein, a composite consisting of 1D cation‐doped TiO2 brookite nanorod (NR) embedded by 0D fullerene is investigated as a top modification buffer for IP‐PV. The cathode buffer is constructed by introducing fullerene to fill the interstitial space of the TiO2 NR matrix. Meanwhile, cations of transition metal Co or Fe are doped into the TiO2 NR to further tune the electronic property. Such a top buffer exhibits multifold advantages, including improved film uniformity, enhanced electron extraction and transfer ability, better energy level matching with perovskite, and stronger moisture resistance. Correspondingly, the resultant IP‐PV displays an efficiency exceeding 22% with a 22‐fold prolonged working lifetime. The strategy not only provides an essential addition to the material inventory for top electron buffers by introducing the 0D:1D composite concept, but also opens a new avenue to optimize perovskite PVs with desirable properties.
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- 2020
19. Antisolvent- and Annealing-Free Deposition for Highly Stable Efficient Perovskite Solar Cells via Modified ZnO
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Dong Yang, Jiangshan Feng, Xuejie Zhu, Xiaodong Ren, Shengzhong Frank Liu, Cong Zhang, Ziyu Wang, Shashank Priya, and Chenyu Wang
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Electron mobility ,Materials science ,Fabrication ,Annealing (metallurgy) ,General Chemical Engineering ,Science ,General Physics and Astronomy ,Medicine (miscellaneous) ,Perovskite solar cell ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,perovskite solar cells ,chelation ,Photovoltaics ,General Materials Science ,Deposition (law) ,Perovskite (structure) ,business.industry ,Communication ,General Engineering ,stability ,Communications ,Chemical engineering ,efficiency ,ZnO ,business ,Layer (electronics) - Abstract
Even though ZnO is commonly used as the ETL in the perovskite solar cell (PSC), the reactivity of perovskite deposited thereupon limits its performance. Herein, an ethylene diamine tetraacetic acid‐complexed ZnO (E‐ZnO) is successfully developed as a significantly improved electron selective layer (ESLs) in perovskite device. It is found that E‐ZnO exhibits higher electron mobility and better matched energy level with perovskite compared to ZnO. In addition, in order to eliminate the proton transfer reaction at the ZnO/perovskite interface, a high quality perovskite film fabrication process that requires neither annealing nor antisolvent is developed. By taking advantages of both E‐ZnO and the new process, the highest efficiency of 20.39% is obtained for PSCs based on E‐ZnO. Moreover, the efficiency of unencapsulated PSCs with E‐ZnO retains 95% of its initial value exposed in an ambient atmosphere after 3604 h. This work provides a feasible path toward high performance of PSCs, and it is believed that the present work will facilitate transition of perovskite photovoltaics in flexible and tandem devices since the annealing‐ and antisolvent‐free technology., The highest efficiency of 20.39% is obtained for perovskite solar cells based on modified ZnO without annealing and antisolvent process. The perovskite devices exhibit unprecedented environmental stability owing to efficient decreased organic ligands on ZnO surface.
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- 2020
20. Understanding Oxidation Resistance of Half-Heusler Alloys for in-Air High Temperature Sustainable Thermoelectric Generators
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Bed Poudel, Udara Saparamadu, Wenjie Li, Hangtian Zhu, Han Byul Kang, Amin Nozariasbmarz, and Shashank Priya
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0303 health sciences ,Materials science ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Engineering physics ,Waste heat recovery unit ,03 medical and health sciences ,Thermoelectric generator ,Thermoelectric effect ,General Materials Science ,Thermal stability ,Electricity ,0210 nano-technology ,business ,Oxidation resistance ,030304 developmental biology - Abstract
High temperature waste heat recovery has gained tremendous interest to generate useful electricity while reducing the harmful impact on the environment. Thermoelectric (TE) solid-state materials enable direct conversion of heat into electricity with high efficiency, thereby offering a practical solution for waste heat recovery. Half-Heusler (hH) alloys are the leading TE materials for medium to high temperature applications, as they exhibit a high figure of merit and mechanical strength at temperatures as high as 973 K. Here we investigate the most promising hH alloys represented as MNiSn, MCoSb, and NbFeSb systems (M = Hf, Zr, and Ti) and provide fundamental understanding of their in-air thermal stability at high temperatures under realistic operating conditions required for energy generation. The understanding of oxidation resistance of TE materials is crucial for their practical deployment in extreme environments without vacuum sealing. The n-type MNiSn and p-type NbFeSb compounds are found to exhibit excellent oxidation resistance at a high temperature of 873 K. The oxidation resistance is enhanced through the presence of an intermetallic Ni-Sn layer for MNiSn and Nb-TiO
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- 2020
21. Bismuth Telluride Thermoelectrics with 8% Module Efficiency for Waste Heat Recovery Application
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Wenjie Li, Amin Nozariasbmarz, Shashank Priya, Bed Poudel, Hangtian Zhu, and Han Byul Kang
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0301 basic medicine ,Materials science ,Materials Science ,Energy Engineering ,02 engineering and technology ,Energy engineering ,Article ,Energy Materials ,Waste heat recovery unit ,03 medical and health sciences ,chemistry.chemical_compound ,Thermoelectric effect ,Energy transformation ,Bismuth telluride ,lcsh:Science ,Multidisciplinary ,business.industry ,Energy conversion efficiency ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,030104 developmental biology ,Thermoelectric generator ,chemistry ,Optoelectronics ,lcsh:Q ,0210 nano-technology ,business - Abstract
Summary Thermoelectric generators (TEGs) offer cost-effective and sustainable solid-state energy conversion mechanism from wasted heat into useful electrical power. Thermoelectric (TE) materials based upon bismuth telluride (BiTe) systems are widely utilized in applications ranging from energy generation to sensing to cooling. There is demand for BiTe materials with high figure of merit (zT) and TEG modules with high conversion efficiency over intermediate temperatures (25°C–250°C). Here we provide fundamental breakthrough in design of BiTe-based TE materials and utilize them to demonstrate modules with outstanding conversion efficiency of 8%, which is 40% higher compared with state-of-the-art commercial modules. The average zT of 1.08 for p-type and 0.84 for n-type bismuth telluride alloys is obtained between 25 and 250°C. The significant enhancement in zT is achieved through compositional and defect engineering in both p- and n-type materials. The high conversion efficiency accelerates the transition of TEGs for waste heat recovery., Graphical Abstract, Highlights • Significant improvement in design of bismuth telluride alloys is demonstrated • High peak and average zT are obtained in both p- and n-type bismuth telluride alloys • Thermoelectric generator with conversion efficiency of 8% is fabricated • High efficiency accelerates the transition of TEGs for waste heat recovery, Energy Engineering; Materials Science; Energy Materials
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- 2020
22. Nature Communications
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Min Gyu Kang, Prashant Kumar, Seyedmeysam Khaleghian, Vireshwar Kumar, Ravi Anant Kishore, Jung-Min Park, Seul-Yi Lee, Hyun Cheol Song, Deepam Maurya, Shashank Priya, Saied Taheri, Yongke Yan, Rammohan Sriramdas, Mechanical Engineering, Materials Science and Engineering, Electrical and Computer Engineering, Institute for Critical Technology and Applied Science, and Center for Tire Research
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Fabrication ,Computer science ,Science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Automotive engineering ,Article ,law.invention ,law ,Wireless ,Electronics ,lcsh:Science ,Strain gauge ,Multidisciplinary ,Inkwell ,ComputingMilieux_THECOMPUTINGPROFESSION ,Graphene ,business.industry ,Energy harvesting ,Continuous monitoring ,General Chemistry ,021001 nanoscience & nanotechnology ,Piezoelectricity ,Sensors and biosensors ,0104 chemical sciences ,lcsh:Q ,0210 nano-technology ,business - Abstract
The transition of autonomous vehicles into fleets requires an advanced control system design that relies on continuous feedback from the tires. Smart tires enable continuous monitoring of dynamic parameters by combining strain sensing with traditional tire functions. Here, we provide breakthrough in this direction by demonstrating tire-integrated system that combines direct mask-less 3D printed strain gauges, flexible piezoelectric energy harvester for powering the sensors and secure wireless data transfer electronics, and machine learning for predictive data analysis. Ink of graphene based material was designed to directly print strain sensor for measuring tire-road interactions under varying driving speeds, normal load, and tire pressure. A secure wireless data transfer hardware powered by a piezoelectric patch is implemented to demonstrate self-powered sensing and wireless communication capability. Combined, this study significantly advances the design and fabrication of cost-effective smart tires by demonstrating practical self-powered wireless strain sensing capability., Designing efficient sensors for smart tires for autonomous vehicles remains a challenge. Here, the authors present a tire-integrated system that combines direct mask-less 3D printed strain gauges, flexible piezoelectric energy harvester for powering the sensors and secure wireless data transfer electronics, and machine learning for predictive data analysis.
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- 2020
23. Nanoscale Texturing and Interfaces in Compositionally Modified Ca3Co4O9 with Enhanced Thermoelectric Performance
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Deepam Maurya, Bed Poudel, Myung Eun Song, Michael A. Meeker, Wenjie Li, Scott T. Huxtable, Heon Joong Lee, Shashank Priya, Min Gyu Kang, Giti A. Khodaparast, and Jue Wang
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Materials science ,Nanostructure ,business.industry ,General Chemical Engineering ,Oxide ,Spark plasma sintering ,Sintering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,01 natural sciences ,Article ,0104 chemical sciences ,lcsh:Chemistry ,chemistry.chemical_compound ,Thermal conductivity ,chemistry ,lcsh:QD1-999 ,Thermoelectric effect ,Optoelectronics ,Figure of merit ,0210 nano-technology ,business - Abstract
Oxide thermoelectric materials are nontoxic, chemically and thermally stable in oxidizing environments, cost-effective, and comparatively simpler to synthesize. However, thermoelectric oxides exhibit comparatively lower figure of merit (ZT) than that of metallic alloy counterparts. In this study, nanoscale texturing and interface engineering were utilized for enhancing the thermoelectric performance of oxide polycrystalline Ca3Co4O9 materials, which were synthesized using conventional sintering and spark plasma sintering (SPS) techniques. Results demonstrated that nanoscale platelets (having layered structure with nanoscale spacing) and metallic inclusions provide effective scattering of phonons, resulting in lower thermal conductivity and higher ZT. Thermoelectric measurement direction was found to have a significant effect on the magnitude of ZT because of the strong anisotropy in the transport properties induced by the layered nanostructure. The peak ZT value for the Ca2.85Lu0.15Co3.95Ga0.05O9 specimen measured along both perpendicular and parallel directions with respect to the SPS pressure axis is found be 0.16 at 630 °C and 0.04 at 580 °C, respectively. The peak ZT of 0.25 at 670 °C was observed for the spark plasma-sintered Ca2.95Ag0.05Co4O9 sample. The estimated output power of 2.15 W was obtained for the full size model, showing high-temperature thermoelectric applicability of this nanostructured material without significant oxidation.
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- 2018
24. High efficiency planar-type perovskite solar cells with negligible hysteresis using EDTA-complexed SnO2
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Ruixia Yang, Shashank Priya, Kai Wang, Dong Yang, Congcong Wu, Guojia Fang, Jiangshan Feng, Shengzhong Frank Liu, Xiaodong Ren, and Xuejie Zhu
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Electron mobility ,Materials science ,Science ,Oxide ,General Physics and Astronomy ,Perovskite solar cell ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,symbols.namesake ,chemistry.chemical_compound ,lcsh:Science ,Perovskite (structure) ,Multidisciplinary ,business.industry ,Fermi level ,Energy conversion efficiency ,General Chemistry ,021001 nanoscience & nanotechnology ,Tin oxide ,0104 chemical sciences ,Hysteresis ,chemistry ,symbols ,Optoelectronics ,lcsh:Q ,0210 nano-technology ,business - Abstract
Even though the mesoporous-type perovskite solar cell (PSC) is known for high efficiency, its planar-type counterpart exhibits lower efficiency and hysteretic response. Herein, we report success in suppressing hysteresis and record efficiency for planar-type devices using EDTA-complexed tin oxide (SnO2) electron-transport layer. The Fermi level of EDTA-complexed SnO2 is better matched with the conduction band of perovskite, leading to high open-circuit voltage. Its electron mobility is about three times larger than that of the SnO2. The record power conversion efficiency of planar-type PSCs with EDTA-complexed SnO2 increases to 21.60% (certified at 21.52% by Newport) with negligible hysteresis. Meanwhile, the low-temperature processed EDTA-complexed SnO2 enables 18.28% efficiency for a flexible device. Moreover, the unsealed PSCs with EDTA-complexed SnO2 degrade only by 8% exposed in an ambient atmosphere after 2880 h, and only by 14% after 120 h under irradiation at 100 mW cm−2. The development of high efficiency planar-type perovskite solar cell has been lagging behind the mesoporous-type counterpart. Here Yang et al. modify the oxide based electron transporting layer with organic acid and obtain planar-type cells with high certified efficiency of 21.5% and decent stability.
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- 2018
25. High-Efficiency Skutterudite Modules at a Low Temperature Gradient
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Han Byul Kang, David Stokes, Wenjie Li, Amin Nozariasbmarz, Shashank Priya, Bed Poudel, and Udara Saparamadu
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Liquid metal ,Control and Optimization ,Materials science ,Energy Engineering and Power Technology ,Thermal grease ,02 engineering and technology ,engineering.material ,010402 general chemistry ,thermoelectric ,01 natural sciences ,lcsh:Technology ,temperature gradient ,Thermal conductivity ,Thermoelectric effect ,Skutterudite ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,Renewable Energy, Sustainability and the Environment ,business.industry ,lcsh:T ,skutterudite ,Energy conversion efficiency ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Temperature gradient ,Thermoelectric generator ,engineering ,Optoelectronics ,0210 nano-technology ,business ,Energy (miscellaneous) ,conversion efficiency - Abstract
Thermoelectric skutterudite materials have been widely investigated for their potential application in mid-temperature waste heat recovery that has not been efficiently utilized A large amount of research has focused on developing materials with a high thermoelectric figure of merit (zT). However, the translation of material properties to device performance has limited success. Here, we demonstrate single-filling n-type Yb0.25Fe0.25Co3.75Sb12 and multi-filling La0.7Ti0.1Ga0.1Fe2.7Co1.3Sb12 skutterudites with a maximum zT of ~1.3 at 740 K and ~0.97 at 760 K. The peak zT of skutterudites usually occurs above 800 K, but, as shown here, the shift in peak zT to lower temperatures is beneficial for enhancing conversion efficiency at a lower hot-side temperature. In this work, we have demonstrated that the Fe-substitution significantly reduces the thermal conductivity of n-type skutterudite, closer to p-type skutterudite thermal conductivity, resulting in a module that is more compatible to operate at elevated temperatures. A uni-couple skutterudite module was fabricated using a molybdenum electrode and Ga&ndash, Sn liquid metal as the thermal interface material. A conversion efficiency of 7.27% at a low temperature gradient of 366 K was achieved, which is among the highest efficiencies reported in the literature at this temperature gradient. These results highlight that peak zT shift and optimized module design can improve conversion efficiency of thermoelectric modules at a low temperature gradient.
- Published
- 2019
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26. Lead-free piezoelectric materials and composites for high power density energy harvesting
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Jungho Ryu, Hyun Cheol Song, Venkateswarlu Annapureddy, Deepam Maurya, Nathan Sharpes, Mahesh Peddigari, Min Gyu Kang, Rammohan Sriramdas, Shashank Priya, Haribabu Palneedi, Liwei D. Geng, Yu U. Wang, and Yongke Yan
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010302 applied physics ,Materials science ,business.industry ,Mechanical Engineering ,02 engineering and technology ,High power density ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Lead zirconate titanate ,01 natural sciences ,Piezoelectricity ,Power (physics) ,Vibration ,chemistry.chemical_compound ,Lead (geology) ,chemistry ,Mechanics of Materials ,0103 physical sciences ,Wireless ,General Materials Science ,Composite material ,0210 nano-technology ,business ,Energy harvesting - Abstract
In the emerging era of Internet of Things (IoT), power sources for wireless sensor nodes in conjunction with efficient and secure wireless data transfer are required. Energy harvesting technologies are promising solution toward meeting the requirements for sustainable power sources for the IoT. In this review, we focus on approaches for harvesting stray vibrations and magnetic field due to their abundance in the environment. Piezoelectric materials and piezoelectric–magnetostrictive [magnetoelectric (ME)] composites can be used to harvest vibration and magnetic field, respectively. Currently, such harvesters use modified lead zirconate titanate (or lead-based) piezoelectric materials and ME composites. However, environmental concerns and government regulations require the development of a suitable lead-free replacement for lead-based piezoelectric materials. In the past decade, several lead-free piezoelectric compositions have been developed and demonstrated with promising piezoelectric response. This paper reviews the significant results reported on lead-free piezoelectric materials with respect to high-density energy harvesting, covering novel processing techniques for improving the piezoelectric response and temperature stability. The review of the state-of-the-art studies on vibration and magnetic field harvesting is provided and the results are used to discuss various strategies for designing high-performance energy harvesting devices.
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- 2018
27. Global Sustainability through Closed-Loop Precision Animal Agriculture
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George T.-C. Chiu, Richard M. Voyles, Mustafa Ayad, Byung-Cheol Min, Robin R. White, Robert A. Nawrocki, Shashank Priya, Shawn S. Donkin, Shreyas Sundaram, K.M. Daniels, and Mythra V. Balakuntala
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Engineering ,business.industry ,Mechanical Engineering ,Food products ,Sustainability ,Robot ,Animal agriculture ,Robotics ,Artificial intelligence ,business ,Closed loop ,Manufacturing engineering - Abstract
The Earth is at a sociotechnical crossroads with humanity hanging in the balance – and high-tech agriculture can help bail us out. Human population growth, increasing urbanization and rising incomes is likely to drastically increase demand for animal agriculture in the coming decades. The US Department of Agriculture (USDA) predicts the need to double global food production by 2050 as the global population increases from 7.3 billion in 2015 to 9.7 billion in 2050 as shown in Fig 1. Much of this growth will be concentrated in the world’s poorest countries where standards of living are set to rise rapidly, increasing the demand for resource-intensive meat and dairy products which has been the historical trend. At the same time, agriculture in the 21st century faces multiple challenges: it must produce more food and fiber to feed a growing population with a smaller rural labor force, produce additional feedstocks for a potentially huge bioenergy market, contribute to overall development in the many agriculture-dependent developing countries, adopt more efficient and sustainable production methods, and adapt to climate change. Additionally, the world’s arable land is already fully employed and shrinking -- the world has lost a third of its arable land due to erosion or pollution in the past 40 years. All these factors put enormous pressure on improving the production efficiency of the world’s supply of food to meet the demand.
- Published
- 2018
28. Quasi-Two-Dimensional Halide Perovskite Single Crystal Photodetector
- Author
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Dong Yang, Yuanyuan Jiang, Shashank Priya, Congcong Wu, and Kai Wang
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Materials science ,business.industry ,General Engineering ,General Physics and Astronomy ,Halide ,Photodetector ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Metal ,Membrane ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Single crystal ,Quantum well ,Perovskite (structure) - Abstract
The robust material stability of the quasi-two-dimensional (quasi-2D) metal halide perovskites has opened the possibility for their usage instead of three-dimensional (3D) perovskites. Further, devices based on large area single crystal membranes have shown increasing promise for photoelectronic applications. However, growing inch-scale quasi-2D perovskite single crystal membranes (quasi-2D PSCMs) has been fundamentally challenging. Here we report a fast synthetic method for synthesizing inch-scale quasi-2D PSCMs, namely (C4H9NH3)n(CH3NH3)n−1PbnI3n+1 (index n = 1, 2, 3, 4, and ∞), and demonstrate their application in a single-crystal photodetector. A quasi-2D PSCM has been grown at the water–air interface where spontaneous alignment of alkylammonium cations and high chemical potentials enable uniform orientation and fast in-plane growth. Structural, optical, and electrical characterizations have been conducted as a function of quantum well thickness, which is determined by the index n. It is shown that th...
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- 2018
29. Materials for energy harvesting: At the forefront of a new wave
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Shashank Priya and Takao Mori
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Flexibility (engineering) ,business.industry ,Photovoltaic system ,Wearable computer ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Software deployment ,Photovoltaics ,Systems engineering ,General Materials Science ,Electronics ,Physical and Theoretical Chemistry ,0210 nano-technology ,business ,Wireless sensor network ,Energy harvesting - Abstract
The rapid increase and dependency on mobile electronic devices and burgeoning importance of sensor network systems and Internet of Things (IoT) to sustain an aging society indicates the strong need to develop battery-less and mobile power sources. Materials for energy harvesting from environmental sources, including mechanical vibrations, magnetic field, heat, and light have become highly relevant for implementation of the IoT vision that requires self-powered wireless sensor networks for sustainable deployment. The articles in this issue cover piezoelectric materials, magnetoelectrics, and thermoelectrics and provide a summary of state-of-the-art energy-harvesting approaches, various material design strategies being targeted by the community, and fundamental challenges in finding an optimum solution and future roadmap. Flexibility of energy harvesters is also emphasized, given the huge potential for wearables. Photovoltaics are briefly covered with respect to wearables and textiles.
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- 2018
30. Exceeding milli-watt powering magneto-mechano-electric generator for standalone-powered electronics
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Woon Ha Yoon, Jong-Woo Kim, Rammohan Sriramdas, Haribabu Palneedi, Jong Jin Choi, Venkateswarlu Annapureddy, Shashank Priya, Suok-Min Na, Kwang Ho Kim, Geon-Tae Hwang, Mahesh Peddigari, Dae-Yong Jeong, Jungho Ryu, Alison B. Flatau, Dong Soo Park, Min Gyu Kang, Cheol Woo Ahn, and Byung Dong Hahn
- Subjects
Materials science ,Magnetic energy ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electric generator ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Piezoelectricity ,0104 chemical sciences ,Magnetic field ,Electromagnetic induction ,law.invention ,Electricity generation ,Nuclear Energy and Engineering ,law ,Environmental Chemistry ,Optoelectronics ,0210 nano-technology ,business ,Energy source ,Magneto - Abstract
In contrast to typical magnetic energy generators that use electromagnetic induction, which are bulky and have low generation efficiency under small magnetic fields at low frequency, magneto-mechano-electric (MME) generators utilizing the magnetoelectric (ME) coupling effect and magnetic interactions are considered promising candidates. MME generators will serve as a ubiquitous autonomous energy source converting stray magnetic noise to useful electric energy for applications in wireless sensor networks (WSN) for the Internet of Things (IoT) and low-power-consuming electronics. The key component in a MME generator is the ME composite consisting of piezoelectric and magnetostrictive materials, which elastically couples the electric and magnetic behaviour of the respective constituent. Here, we report a MME generator consisting of a crystallographically oriented Pb(Mg1/3Nb2/3)O3–Pb(Zr,Ti)O3 piezoelectric single crystal macro-fibre composite and a highly textured magnetostrictive Fe–Ga alloy, which exhibits an exceptionally high rectified DC output power density of 3.22 mW cm−3. The large energy generation in this structure is ascribed to the coupling between the strong anisotropic properties of the piezoelectric single crystal fibres and textured Fe–Ga magnetostrictive alloy. A smart watch with IoT sensors was driven by the MME generator under a 700 μT magnetic field.
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- 2018
31. A review on design and performance of thermomagnetic devices
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Ravi Anant Kishore and Shashank Priya
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Renewable Energy, Sustainability and the Environment ,business.industry ,Computer science ,020209 energy ,Electrical engineering ,02 engineering and technology ,Thermomagnetic convection ,021001 nanoscience & nanotechnology ,Engineering physics ,Electricity generation ,Soft magnet ,0202 electrical engineering, electronic engineering, information engineering ,0210 nano-technology ,business ,Energy harvesting ,Efficient energy use - Abstract
Thermomagnetic energy harvesting technology has not received significant attention despite great potential for generating electricity from low thermal gradient near room temperature. This review summarizes the findings reported in literature covering the broad topical areas within thermomagnetic energy harvesting and provides perspective on the potential applications of this technology. The information has been organized chronologically in order to provide systematic understanding of the concepts and evolution of the device designs. Both, active and passive types of thermomagnetic energy harvesters have been included in the paper. The selection of suitable thermomagnetic material is key towards achieving an efficient energy generation device. Therefore, various material compositions have been discussed and their thermomagnetic behavior has been elucidated to provide guidance for their implementation in future devices.
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- 2018
32. A comprehensive optimization study on Bi2Te3-based thermoelectric generators using the Taguchi method
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Shashank Priya, Prashant Kumar, and Ravi Anant Kishore
- Subjects
Renewable Energy, Sustainability and the Environment ,business.industry ,Computer science ,020209 energy ,Process (computing) ,Energy Engineering and Power Technology ,Fourth stage ,02 engineering and technology ,Heat sink ,Renewable energy ,Waste heat recovery unit ,Taguchi methods ,Fuel Technology ,Thermoelectric generator ,Thermoelectric effect ,0202 electrical engineering, electronic engineering, information engineering ,business ,Process engineering - Abstract
Low-grade waste heat recovery is a promising source of renewable energy; however, there are practical challenges in the recovery process. Thermoelectric generators (TEGs) are a viable solution, but their efficiency remains low, thereby limiting their implementation. The performance of TEGs can be enhanced by optimizing the module configuration; however, optimizing all the parameters experimentally using traditional experimental techniques will require several trials, and therefore, it is cumbersome and expensive. Here, we demonstrate the Taguchi method for optimizing TEG modules and demonstrate that full optimization can be achieved in just 25 experiments. The optimization has been achieved in four stages. In the first stage, a numerical model of thermoelectricity is developed and used in the second stage to optimize key geometric parameters of TEGs through the Taguchi method. In the third stage, the Taguchi method is used to optimize the geometric dimensions of the heat sink. Lastly, in the fourth stage, the effect of operating conditions on the performance of TEGs is investigated. The results reveal that the Taguchi method is capable of predicting the near-optimal configuration of TEGs.
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- 2018
33. Ultra-Low Resonant Piezoelectric MEMS Energy Harvester With High Power Density
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William T. Reynolds, Min Gyu Kang, Dae-Yong Jeong, Prashant Kumar, Shashank Priya, Hyun Cheol Song, Deepam Maurya, and Chong Yun Kang
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Materials science ,business.industry ,Mechanical Engineering ,020208 electrical & electronic engineering ,Electrical engineering ,Natural frequency ,02 engineering and technology ,Low frequency ,021001 nanoscience & nanotechnology ,Polarization (waves) ,Vibration ,Normal mode ,Excited state ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Atomic physics ,Proof mass ,0210 nano-technology ,business ,Energy harvesting - Abstract
We demonstrate a microscale vibration energy harvester exhibiting an ultra-low resonance frequency and high power density. A spiral shaped microelectromechanical system (MEMS) energy harvester was designed to harvest ambient vibrations at a low frequency ( $\mu \text{m}$ -thickness exhibiting remanent polarization of 36.2 $\mu \text{C}$ /cm2 and longitudinal piezoelectric constant of 155 pm/V was synthesized to achieve high efficiency mechanical to electrical conversion. The experimental results demonstrate an ultra-low natural frequency of 48 Hz for MEMS harvester. This is one of the lowest resonance frequency reported for the piezoelectric MEMS energy harvester. Further, the position of the natural frequency was controlled by modulating the number of spiral turns and weight of the proof mass. The vibration mode shape and stress distribution were validated through a finite element analysis. The maximum output power of 23.3 nW was obtained from the five turns spiral MEMS energy harvester excited at 0.25 g acceleration and 68Hz. The normalized area and the volumetric energy density were measured to be $5.04\times 10^{-4}~ \mu \text{W}$ /mm $^{2}~\cdot ~\text{g}^{2}~\cdot$ Hz and $4.92\times 10^{-2} ~ \mu \text{W}$ /mm $^{3}~\cdot ~\text{g}^{2}~\cdot$ Hz, respectively. [2017-0018]
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- 2017
34. Interface Controlled Growth of Single-Crystalline PbTiO3 Nanostructured Arrays
- Author
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William T. Reynolds, Shashank Priya, Mohan Sanghadasa, Hyun Cheol Song, and Deepam Maurya
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Materials science ,business.industry ,Nucleation ,Nanotechnology ,02 engineering and technology ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Pyroelectricity ,Crystal ,General Energy ,Optoelectronics ,Physical and Theoretical Chemistry ,0210 nano-technology ,business ,Single crystal ,Perovskite (structure) - Abstract
PbTiO3 (PTO) ferroelectric perovskite has appealing electromechanical characteristics such as low aging rate of the dielectric constant, a high pyroelectric coefficient, a high piezoelectric voltage constant (gij), and a high Curie temperature of 490 °C. However, the high tetragonality of PTO ceramics makes them difficult to be synthesized via conventional high-temperature techniques. Here, a novel synthesis methodology is reported that results in epitaxial growth of a vertically aligned array of PTO nanofibers on a Ti metal substrate. High quality single crystal PTO nanofibers oriented along the [001] PTO direction were obtained on a (110) oriented TiO2 seed layer using a low-temperature hydrothermal synthesis technique. Fundamental understanding of the nucleation and growth criterion is provided through a combination of modeling of the geometric matching of crystal surfaces and experiments detailing the role of underlying TiO2 phase and interplanar atomic configuration. Crystal matching revealed good co...
- Published
- 2017
35. The permittivity and refractive index measurements of doped barium titanate (BT-BCN)
- Author
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Michael Clavel, Sreenivasulu Gollapudi, Deepam Maurya, Mantu K. Hudait, Souvik Kundu, Alejandro Sosa, Giti A. Khodaparast, Michael A. Meeker, Rathsara R. H. H. Mudiyanselage, Shashank Priya, and Min Gyu Kang
- Subjects
0301 basic medicine ,Permittivity ,Materials science ,Relative permittivity ,02 engineering and technology ,Dielectric ,Inorganic Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Optics ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Spectroscopy ,business.industry ,Organic Chemistry ,Biasing ,021001 nanoscience & nanotechnology ,Ferroelectricity ,Piezoelectricity ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,030104 developmental biology ,chemistry ,Barium titanate ,Optoelectronics ,0210 nano-technology ,business ,Refractive index - Abstract
While piezoelectric- ferroelectric materials offer great potential for nonvolatile random access memory, most commonly implemented ferroelectrics contain lead which imposes a challenge in meeting environmental regulations. One promising candidate for lead-free, ferroelectric material based memory is ( 1 − x ) B a T i O 3 − x B a ( C u 1 / 3 N b 2 / 3 ) O 3 (BT-BCN), x = 0.025 . The samples studied here were grown on a Si substrate with an HfO2 buffer layer, thereby preventing the interdiffusion of BT-BTCN into Si. This study provides further insight into the physical behavior of BT-BCN that will strengthen the foundation for developing switching devices. The sample thicknesses ranged from 1.5 to 120 nm, and piezoelectric force microscopy was employed in order to understand the local ferroelectric behaviors. Dielectric constant as a function of frequency demonstrated enhanced frequency dispersion indicating the polar nature of the composition. The relative permittivity was found to change significantly with varying bias voltage and exhibited a tunability of 82%. The difference in the peak position during up and down sweeps is due to the presence of the spontaneous polarization. Furthermore, reflectometry was performed to determine the refractive index of samples with differing thicknesses. Our results demonstrate that refractive indices are similar to that of barium titanate. This is a promising result indicating that improved ferroelectric properties are obtained without compromising the optical properties.
- Published
- 2017
36. A modeling comparison between a two-stage and three-stage cascaded thermoelectric generator
- Author
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Zhiting Tian, David Stokes, Eurydice Kanimba, Shashank Priya, Matthew R. Pearson, and Jeff Sharp
- Subjects
Middle stage ,Materials science ,020209 energy ,Energy Engineering and Power Technology ,02 engineering and technology ,engineering.material ,Automotive engineering ,chemistry.chemical_compound ,Robustness (computer science) ,Thermoelectric effect ,0202 electrical engineering, electronic engineering, information engineering ,Skutterudite ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Three stage ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,021001 nanoscience & nanotechnology ,Lead telluride ,Design for manufacturability ,Thermoelectric generator ,chemistry ,engineering ,0210 nano-technology ,business - Abstract
In this work, a comparison between the performance of two- and three-stage cascaded thermoelectric generator (TEG) devices is analyzed based on a prescribed maximum hot side temperature of 973 K, an imposed maximum heat input of 505 W, and a fixed cold side temperature of 473 K. Half-Heusler is used as a thermoelectric (TE) material in the top higher temperature stage and skutterudite as a TE in the bottom lower temperature stage for the two-stage structure. Lead telluride is added in the middle stage to form the three-stage structure. Based on the prescribed constraints, the two-stage cascaded TEG is found to produce a power output of 42 W with an efficiency of 8.3%. The three-stage cascaded TEG produces a power output of 51 W with an efficiency of 10.2%. The three-stage cascaded TEG produces 21% more power than the two-stage does; however, if the system complexity, mechanical robustness, manufacturability, and/or cost of three-stage cascaded TEG outweigh the 21% percent power production increase, the two-stage TEG could be preferable.
- Published
- 2017
37. Low-frequency Zigzag energy harvesters operating in torsion-dominant mode
- Author
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Hyeon Lee, Shashank Priya, Nathan Sharpes, Abdessattar Abdelkefi, and Hichem Abdelmoula
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Engineering ,business.industry ,020209 energy ,Mechanical Engineering ,Acoustics ,Torsion (mechanics) ,02 engineering and technology ,Building and Construction ,Structural engineering ,Management, Monitoring, Policy and Law ,Low frequency ,021001 nanoscience & nanotechnology ,Piezoelectricity ,Finite element method ,General Energy ,Zigzag ,Normal mode ,0202 electrical engineering, electronic engineering, information engineering ,0210 nano-technology ,business ,Energy harvesting ,Voltage - Abstract
Natural frequencies and mode shapes of low frequency (
- Published
- 2017
38. Corrigendum to 'Artemisinin (ART)-Induced 'perovskite/perovskite' bilayer structured photovoltaics' [Nano Energy 78 (2020) 105133]
- Author
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Shashank Priya, Yuchen Hou, Dong Yang, Kai Wang, Liam Brownlie, Tao Ye, Ke Wang, and Congcong Wu
- Subjects
Materials science ,Natural materials ,Renewable Energy, Sustainability and the Environment ,Photovoltaics ,business.industry ,Acknowledgement ,Library science ,General Materials Science ,Electrical and Electronic Engineering ,business ,Sentence - Abstract
The authors regret a minor error in the funding number mentioned in the first sentence in acknowledgement section. Herein, we have corrected the funding number, which is described below: The first sentence of acknowledgement section in the original publication reads: “Y. H. acknowledges the financial support through the AFOSR Natural Materials and Biophysics program (Air Force Office of Scientific Research under award number FA9550-17-1-0341)”. It should be corrected as “Y. H. acknowledges the financial support through the AFOSR Natural Materials and Biophysics program (Air Force Office of Scientific Research under award number FA9550-18-1-0233)”. These revises do not affect the conclusion of the manuscript. The authors would like to apologise for any inconvenience caused.
- Published
- 2021
39. Optical properties of Pb0.52Zr0.48TiO3 nanorod arrays: second harmonic generation and multiphoton carrier dynamics
- Author
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Han Byul Kang, John Burton, Ada J Morral, Giti A. Khodaparast, Kiara McMillan, Gabriella Gagliano, Min Gyu Kang, Christopher J. Stanton, Shashank Priya, Brenden Magill, and Rathsara R. H. H. Mudiyanselage
- Subjects
Materials science ,second harmonic generation ,multiferroics ,business.industry ,PZT ,Quantum sensor ,Second-harmonic generation ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,time resolved spectroscopy ,Optoelectronics ,Multiferroics ,Nanorod ,quantum sensing ,Electrical and Electronic Engineering ,Time-resolved spectroscopy ,nanorods ,Carrier dynamics ,business - Abstract
Nonlinear optical properties of poled and unpoled, lead zirconate-titanate (Pb0.52Zr0.48TiO3) nanorod arrays, grown on Pt-coated Si with similar to 200 nm diameter and similar to 600 nm height, were investigated. Clear signatures of second harmonic generations (SHG), from 490-525 nm (2.38-2.53 eV) at room temperature, were observed. Furthermore, time resolved differential reflectivity measurements were performed to study dynamical properties of photoexcited carriers in the range of 690-1000 nm where multiphoton processes were responsible for the photo-excitations. We compared this excitation scheme, which is sensitive mainly to the surface states, to when the photoexcited energy (similar to 3.1 eV) was close to the band gap of the nanorods. Our results offer promises for employing these nanostructures in nonlinear photonic applications. Air Force Office of Scientific ResearchUnited States Department of DefenseAir Force Office of Scientific Research (AFOSR) [FA9550-17-1-0341]; DURIP [FA9550-16-1-0358]; Clare Boothe Luce Program at Virginia Tech Published version This material is based upon work supported by the Air Force Office of Scientific Research under Award No. FA9550-17-1-0341 and DURIP funding (FA9550-16-1-0358). Kiara McMillan and Ada Morral acknowledge the support from Clare Boothe Luce Program at Virginia Tech.
- Published
- 2021
40. High-performance half-Heusler thermoelectric devices through direct bonding technique
- Author
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Hangtian Zhu, Han Byul Kang, Amin Nozariasbmarz, Shashank Priya, Udara Saparamadu, Bed Poudel, Carter Dettor, and Wenjie Li
- Subjects
Fabrication ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Contact resistance ,Energy conversion efficiency ,Energy Engineering and Power Technology ,02 engineering and technology ,Direct bonding ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electrical contacts ,0104 chemical sciences ,Thermoelectric generator ,Thermoelectric effect ,Figure of merit ,Optoelectronics ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,business - Abstract
Solid-state thermoelectric generators (TEGs) are promising solution for waste heat recovery. However, they typically suffer from lower conversion efficiency, lack of reliable high temperature device fabrication process and long-term stability. In order to realize high electrical conversion efficiency (ECE) in TEGs, it is critical that in conjunction with high TE materials figure of merit, zT, there is also a reliable TE module fabrication process. This study demonstrates the TEG fabrication process that results in reduced thermal and electrical contact resistances between metal electrodes and TE legs, even at high temperatures (>600 °C). The fabrication approach is demonstrated using p-type ZrCoSb-based and n-type ZrNiSn-based half-Heusler TE materials. High temperature brazing material is used as a filler that enables direct bonding of TE legs to the copper electrode without metallizing legs. This technique improves the TEG performance and stability at high temperatures by minimizing the contact resistance and diffusion at TE leg/electrode interface. The fabricated modules exhibit a high power density of ~11.5 Wcm−2 and an ECE of 9.5% at 670 °C temperature gradient. The module was exposed to longtime soaking at 550 °C in air and was found to exhibit negligible deterioration. These results are highly promising for advancing the TE modules in waste heat recovery applications.
- Published
- 2021
41. Fabrication of Lead-Free (CH3 NH3 )3 Bi2 I9 Perovskite Photovoltaics in Ethanol Solvent
- Author
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Yongke Yan, Jian Pu, Shashank Priya, Haijin Li, Jian Li, Congcong Wu, and Bo Chi
- Subjects
Materials science ,Fabrication ,business.industry ,General Chemical Engineering ,Inorganic chemistry ,Photovoltaic system ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Environmentally friendly ,0104 chemical sciences ,Bismuth ,Solvent ,General Energy ,chemistry ,Chemical engineering ,Photovoltaics ,Environmental Chemistry ,General Materials Science ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
The toxicity of lead present in organohalide perovskites and the hazardous solvent system used for their synthesis hinders the deployment of perovskite solar cells (PSCs). Here, we report an environmentally friendly route for synthesis of bismuth based lead-free (CH3NH3)3Bi2I9 perovskites that utilize ethanol as the solvent. Using this method, dense and homogeneous microstructure was obtained, compared the porous rough microstructure obtained by DMF solution. Thus, the photovoltaic performance was enhanced and open voltage as high as 0.84 V can be obtained.
- Published
- 2017
42. Voltage-Controlled Capacitor—Feasibility Demonstration in DC–DC Converters
- Author
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Lujie Zhang, Andrew P. Ritter, Ben Guo, Khai D. T. Ngo, Craig W. Nies, Rolando Burgos, Suman Dwari, and Shashank Priya
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010302 applied physics ,Engineering ,business.industry ,Buck converter ,020208 electrical & electronic engineering ,Voltage divider ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,02 engineering and technology ,Decoupling capacitor ,01 natural sciences ,Capacitance ,law.invention ,Capacitor ,Parasitic capacitance ,Hardware_GENERAL ,law ,Pre-charge ,0103 physical sciences ,Hardware_INTEGRATEDCIRCUITS ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Equivalent circuit ,Electrical and Electronic Engineering ,business - Abstract
This letter presents a voltage-controlled capacitor that varies from 20% to 100% of the rated capacitance (1 μ F) with a control voltage from half of the voltage rating to 0 V. Capacitance, self-resonant frequency, and equivalent series resistance were measured with respect to the control voltage. An equivalent circuit and a nonlinear model derived from relationship between permittivity and electric field were created and implemented in SPICE. A buck converter with input of 12 V, output of 5 V, and switching frequency of 500 kHz was built to demonstrate the change from 85% to 40% of the rated capacitance of the voltage-controlled capacitor. The error between the simulation and experiment was limited within 10%, which verifies the model.
- Published
- 2017
43. Modulated Magneto-Thermal Response of La0.85Sr0.15MnO3 and (Ni0.6Cu0.2Zn0.2)Fe2O4 Composites for Thermal Energy Harvesters
- Author
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Yuan Zhou, Hyun Cheol Song, Deepam Maurya, Myung Eun Song, Nana Kwame Yamoah, David Gray, Shashank Priya, Menka Jain, Jinsung Chun, A. McDannald, and Dhananjay Kumar
- Subjects
010302 applied physics ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0103 physical sciences ,Thermal ,Electrochemistry ,Electrical and Electronic Engineering ,Composite material ,0210 nano-technology ,business ,Magneto ,Thermal energy - Abstract
The magneto-thermoelectric generator (MTG) converts wasted thermal energy into electrical energy in two steps. The first step involves thermal to mechanical energy conversion through balance of magnetic and elastic forces and the second step involves mechanical to electrical energy conversion through piezoelectric effect. The requirements for soft magnetic material in improving the efficiency of first step were identified and met through the design of a composite architecture. The Curie temperature of La(1–x)SrxMnO3 can be engineered to be near room temperature by modifying the Sr content. Composite of La0.85Sr0.15MnO3 (LSMO) and Ni0.6Cu0.2Zn0.2Fe2O4 (NCZF) was found to exhibit high saturation (Ms) and remnant (Mr) magnetization magnitude while maintaining the soft magnetic nature. Two-step sintering was found to prevent the inter-diffusion of LSMO and NCZF phases and provided high density without grain growth. The LSMO-NCZF (70:30 wt%) composite exhibited a large variation in Ms with respect to the change in temperature near Curie temperature which meets the requirements for efficient operation of MTG. The fabricated MTG using LSMO-NCZF (70:30 wt%) composite reached 0.2 Hz operational frequency and generated electrical output voltage of 2 Vp–p and peak power of 17 µW under the thermal gradient of 80 °C (0 °C/80 °C).
- Published
- 2017
44. A Review on Piezoelectric Energy Harvesting: Materials, Methods, and Circuits
- Author
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Anuj Chopra, Shashank Priya, Jungho Ryu, Sang-Gook Kim, Isaku Kanno, Liao Wu, Ronald G. Polcawich, Dong Sam Ha, Hyun Cheol Song, Ronnie Varghese, and Yuan Zhou
- Subjects
010302 applied physics ,Microelectromechanical systems ,Cantilever ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Piezoelectricity ,0103 physical sciences ,Electrochemistry ,Electromechanical coupling ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Energy harvesting ,Non linear resonance ,Electronic circuit ,Power density - Abstract
Piezoelectric microelectromechanical systems (PiezoMEMS) are attractive for developing next generation self-powered microsystems. PiezoMEMS promises to eliminate the costly assembly for microsensors/microsystems and provide various mechanisms for recharging the batteries, thereby, moving us closer towards batteryless wireless sensors systems and networks. In order to achieve practical implementation of this technology, a fully assembled energy harvester on the order of a quarter size dollar coin (diameter=24.26 mm, thickness=1.75 mm) should be able to generate about 100 μW continuous power from low frequency ambient vibrations (below 100 Hz). This paper reviews the state-of-the-art in microscale piezoelectric energy harvesting, summarizing key metrics such as power density and bandwidth of reported structures at low frequency input. This paper also describes the recent advancements in piezoelectric materials and resonator structures. Epitaxial growth and grain texturing of piezoelectric materials is being developed to achieve much higher energy conversion efficiency. For embedded medical systems, lead-free piezoelectric thin films are being developed and MEMS processes for these new classes of materials are being investigated. Non-linear resonating beams for wide bandwidth resonance are also reviewed as they would enable wide bandwidth and low frequency operation of energy harvesters. Particle/granule spray deposition techniques such as aerosol-deposition (AD) and granule spray in vacuum (GSV) are being matured to realize the meso-scale structures in a rapid manner. Another important element of an energy harvester is a power management circuit, which should maximize the net energy harvested. Towards this objective, it is essential for the power management circuit of a small-scale energy harvester to dissipate minimal power, and thus it requires special circuit design techniques and a simple maximum power point tracking scheme. Overall, the progress made by the research and industrial community has brought the energy harvesting technology closer to the practical applications in near future.
- Published
- 2017
45. Low-grade waste heat recovery using the reverse magnetocaloric effect
- Author
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Ravi Anant Kishore and Shashank Priya
- Subjects
010302 applied physics ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,Thermodynamics ,02 engineering and technology ,Heat sink ,021001 nanoscience & nanotechnology ,01 natural sciences ,Waste heat recovery unit ,Fuel Technology ,Thermoelectric generator ,Operating temperature ,Waste heat ,0103 physical sciences ,Magnetic refrigeration ,Curie temperature ,0210 nano-technology ,business ,Thermal energy - Abstract
According to a recent study by Lawrence Livermore National Laboratory, about 59.1 quadrillion BTU of energy produced in the United States is rejected to the atmosphere, mostly in the form of waste heat. A major portion of the total rejected thermal energy has a low temperature (less than 230 °C), classified as low-grade waste heat. This energy loss is the result of the fact that current thermal energy harvesting technologies, primarily thermoelectric generators, have poor efficiency at low temperature gradients and therefore are not cost-effective. This study investigates the possibility of low-grade waste heat recovery using magnetocaloric materials, which were developed mainly for magnetic refrigeration. The working principle of energy harvesters using the reverse magnetocaloric cycle is described using thermodynamic analysis and the performance of more than 60 magnetocaloric materials is compared under different operating temperature conditions. Considering the ambient atmosphere as the heat sink (temperature ∼ 25 °C), it was found that oxide-based magnetocaloric materials, such as La2/3Ba1/3MnO2.98 (Curie temperature ∼ 38 °C), have a working potential as high as 53.5 J per kg per cycle at a heat source temperature of 50 °C. The working potential increases to 77.4 J per kg per cycle, when the heat source temperature is increased to 75 °C, and it further increases to 87.8 J per kg per cycle at a heat source temperature of 100 °C. The working potential up to 100 J per kg per cycle at a heat source temperature of 100 °C was estimated for a few other materials with higher Curie temperature, such as Gd5Si4 (Curie temperature ∼ 65 °C) and La2/3Ba1/3MnO3 (Curie temperature ∼ 63 °C).
- Published
- 2017
46. Enhanced piezoluminescence in non-stoichiometric ZnS:Cu microparticle based light emitting elastomers
- Author
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Min Gyu Kang, Deepam Maurya, Jiayong Gan, Robert J. Bodnar, Michael A. Meeker, James E. Mahaney, Shashank Priya, and Giti A. Khodaparast
- Subjects
Brightness ,Piezoluminescence ,Materials science ,Polydimethylsiloxane ,business.industry ,02 engineering and technology ,General Chemistry ,Electron ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Elastomer ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Energy transformation ,Optoelectronics ,Spontaneous emission ,0210 nano-technology ,business ,Mechanoluminescence - Abstract
Piezoluminescence (PZL), also referred to as mechanoluminescence (ML), is a promising energy conversion mechanism for realizing mechanically driven photon sources including handheld displays, lighting, bioimaging and sensing applications. However, the realization of a visible PZL intensity at room temperature from low mechanical stresses has been fundamentally challenging. Herein, we describe a PZL elastomer exhibiting significantly enhanced brightness under ambient conditions. The elastomer consisted of defect-engineered non-stoichiometric Cu-doped ZnS (ZnS:Cu) microparticles in a polydimethylsiloxane (PDMS) matrix. The role of the defect structure was found to be the controlling parameter in the nature of PZL emission. Hydrogenation treatment was designed to induce a controlled concentration of sulfur vacancies that provided the trapped electrons, which had a strong correlation with the PZL performance of ZnS:Cu. An optimum electron concentration was necessary in order to maximize the PZL intensity due to an adequate electron energy transfer ratio between non-radiative recombination (NRR) and thermal radiative recombination (TRR). The light-emitting elastomer with an optimum content of PZL particles maximized the stress-mediated electroluminescence–piezoelectric coupling, enabling visible PZL brightness under indoor light conditions.
- Published
- 2017
47. Voltage-Controlled Tunable Capacitor based Resonant Power Converter
- Author
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Ben Guo, Suman Dwari, and Shashank Priya
- Subjects
Materials science ,business.industry ,05 social sciences ,Electrical engineering ,020207 software engineering ,02 engineering and technology ,Power factor ,Converters ,Capacitance ,law.invention ,Capacitor ,Hardware_GENERAL ,law ,EMI ,visual_art ,Electronic component ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,Harmonic ,0501 psychology and cognitive sciences ,business ,050107 human factors ,Voltage - Abstract
The conventional resonant converters are based on fixed passive components which are required to be operated by variable switching frequency control with limited regulation capabilities under changing operating conditions. This includes the variations of load, source, and components. The variable switching frequency operation not only increases the size of the EMI and the harmonic filters but also reduces the efficiency of a converter. To address these challenges, a fixed frequency resonant power converter based on voltage-controlled tunable capacitor is proposed in this work. In the proposed converter, the capacitance of the resonant tank is varied to control the gain of the resonant converter by changing the dc control voltage across a tunable capacitor bank. Detailed analysis and design of the proposed converter, utilizing LLC resonant tank structure, for achieving high efficiency and fixed frequency operation are presented. Experimental results are presented to validate the operation and high performances of the proposed resonant converter.
- Published
- 2019
48. Bacteriorhodopsin Enhances Efficiency of Perovskite Solar Cells
- Author
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Congcong Wu, Renugopalakrishnan Venkatesan, Rainer Koch, Zhaoning Song, Bernardo Barbiellini, Ponisseril Somasundaran, Subhabrata Das, Shashank Priya, Yuchen Hou, Lappeenrannan-Lahden teknillinen yliopisto LUT, Lappeenranta-Lahti University of Technology LUT, and fi=School of Engineering Science|en=School of Engineering Science
- Subjects
Photoluminescence ,Materials science ,Perovskite solar cell ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,fill factor ,law.invention ,chemistry.chemical_compound ,law ,Solar cell ,General Materials Science ,Purcell effect ,perovskite ,Perovskite (structure) ,biology ,business.industry ,bacteriorhodopsin ,Photovoltaic system ,Bacteriorhodopsin ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Polycrystalline silicon ,chemistry ,Titanium dioxide ,engineering ,biology.protein ,FRET ,Optoelectronics ,photoluminescence ,0210 nano-technology ,business - Abstract
Recently, halide perovskites have upstaged decades of solar cell development by reaching power conversion efficiencies that surpass the performance of polycrystalline silicon. The efficiency improvement in the perovskite cells is related to repeated recycling between photons and electron–hole pairs, reduced recombination losses, and increased carrier lifetimes. Here, we demonstrate a novel approach toward augmenting the perovskite solar cell efficiency by invoking the Förster Resonance Energy Transfer (FRET) mechanism. FRET occurs in the near-field region as the bacteriorhodopsin (bR) protein, and perovskite has similar optical gaps. Titanium dioxide functionalized with the bR protein is shown to accelerate the electron injection from excitons produced in the perovskite layer. FRET predicts the strength of long-range excitonic transport between the perovskite and bR layers. Solar cells incorporating TiO2/bR layers are found to exhibit much higher photovoltaic performance as compared to baseline cells without bR. These results open the opportunity to develop a new class of bioperovskite solar cells with improved performance and stability. Post-print / Final draft
- Published
- 2019
49. Stable Efficiency Exceeding 20.6% for Inverted Perovskite Solar Cells through Polymer-Optimized PCBM Electron-Transport Layers
- Author
-
Congcong Wu, Ruixia Yang, Yuchen Hou, Shashank Priya, Dong Yang, Xiaorong Zhang, Shengzhong Liu, Yuanyuan Jiang, and Kai Wang
- Subjects
Electron mobility ,Materials science ,Fullerene ,Electron capture ,business.industry ,Mechanical Engineering ,Perovskite solar cell ,Relative permittivity ,Bioengineering ,02 engineering and technology ,General Chemistry ,Electron ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electron transport chain ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
Fullerene derivative, such as [6,6]-phenyl C61 butyric acid methyl ester (PCBM), is widely used as an electron-transport layer (ETL) in inverted perovskite solar cell (PSC). However, its low electron mobility, complexity in achieving quality film formation, and severe nonradiative recombination at perovskite/PCBM interface due to the large electron capture region, lead to lower efficiency for inverted PSCs compared to the normal structures. Herein, we demonstrate an effective and practical strategy to overcome these challenges. Conjugated n-type polymeric materials are mixed together with PCBM to form a homogeneous bulk-mixed (HBM) continuous film with high electron mobility and suitable energy level. HBM film is found to completely cap the perovskite surface to enhance the electron extraction. The critical electron capture radius of the HBM decreases to 12.52 nm from 14.89 nm of PCBM due to the large relative permittivity, resulting in reduced nonradiative recombination at perovskite/HBM interface. The efficiency of inverted PSCs with HBM ETLs exceeds 20.6% with a high fill factor of 0.82. Further, the stability of devices is improved owing to the high hydrophobicity of the HBM ETLs. Under ambient air condition after 45 days, the efficiency of inverted PSCs based on HBM remains 80% of the initial value. This is significantly higher than the control devices which retain only 48% of the initial value under similar aging conditions. We believe these breakthroughs in improving efficiency and stability of inverted PSCs will expedite their transition.
- Published
- 2019
50. Efficient production of phosphorene nanosheets via shear stress mediated exfoliation for low‐temperature perovskite solar cells
- Author
-
Joseph G. Shapter, Thomas J. Macdonald, Congcong Wu, Christopher T. Gibson, Michael J. Ford, Kasturi Vimalanathan, Abdulaziz S. R. Bati, Sherif Abdulkader Tawfik, Colin L. Raston, Shashank Priya, LePing Yu, and Munkhbayar Batmunkh
- Subjects
Electron mobility ,Materials science ,business.industry ,Energy conversion efficiency ,Photovoltaic system ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,Exfoliation joint ,0104 chemical sciences ,Phosphorene ,chemistry.chemical_compound ,Planar ,chemistry ,Optoelectronics ,General Materials Science ,Fluidics ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
A simple and fast "top-down" protocol is introduced herein to prepare solution processable few-layer phosphorene nanosheets using vortex fluidic mediated exfoliation under near-infrared (NIR) pulsed laser irradiation. This novel shear-exfoliation method requires short processing times and produces highly crystalline, atomically thin phosphorene nanosheets (4.3 +/- 0.4 nm). The as-prepared phosphorene nanosheets are used as an effective electron transporting material (ETM) for low-temperature processed, planar n-i-p perovskite solar cells (PSCs). With the addition of phosphorene, the average power conversion efficiency (PCE) increases from 14.32% to 16.53% with a maximum PCE of 17.85% observed for the phosphorene incorporated PSCs which is comparable to the devices made using the traditional high-temperature protocol. Experimental and theoretical (density-functional theory) investigations reveal the PCE improvements are due to the high carrier mobility and suitable band energy alignment of the phosphorene. The work not only paves the way for novel synthesis of 2D materials, but also opens a new avenue in using phosphorene as an efficient ETM in photovoltaic devices.
- Published
- 2019
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