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412 results on '"Baldo, Marc A"'

1. Triplet Exciton Sensitization of Silicon Mediated by Defect States in Hafnium Oxynitride

Author

Nagaya, Narumi, Alexiu, Alexandra, Perkinson, Collin F., Nix, Oliver M., Bawendi, Moungi G., Tisdale, William A., Van Voorhis, Troy, and Baldo, Marc A.

Subjects
Condensed Matter - Materials Science, Physics - Chemical Physics
Abstract

Singlet exciton fission has the potential to increase the efficiency of crystalline silicon solar cells beyond the conventional single junction limit. Perhaps the largest obstacle to achieving this enhancement is uncertainty about energy coupling mechanisms at the interfaces between silicon and exciton fission materials such as tetracene. Here, the previously reported silicon-hafnium oxynitride-tetracene structure is studied and a combination of magnetic-field-dependent silicon photoluminescence measurements and density functional theory calculations is used to probe the influence of the interlayer composition on the triplet transfer process across the hafnium oxynitride interlayer. It is found that hafnium oxide interlayers do not show triplet exciton sensitization of silicon, and that nitrogen content in hafnium oxynitride layers is correlated with enhanced sensitization. Calculation results reveal that defects in hafnium oxynitride interlayers with higher nitrogen content introduce states close to the band-edge of silicon, which can mediate the triplet exciton transfer process. Some defects introduce additional deleterious mid-gap states, which may explain observed silicon photoluminescence quenching. These results show that band-edge states can mediate the triplet exciton transfer process, potentially through a sequential charge transfer mechanism., Comment: 30 pages, 20 figures

Published
2024
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2. Exciton Fission Enhanced Silicon Solar Cell

Author

Nagaya, Narumi, Lee, Kangmin, Perkinson, Collin F., Li, Aaron, Lee, Youri, Zhong, Xinjue, Lee, Sujin, Weisburn, Leah P., Baikie, Tomi K., Bawendi, Moungi G., Van Voorhis, Troy, Tisdale, William A., Kahn, Antoine, Seo, Kwanyong, and Baldo, Marc A.

Subjects
Condensed Matter - Materials Science, Physics - Chemical Physics
Abstract

While silicon solar cells dominate global photovoltaic energy production, their continued improvement is hindered by the single junction limit. One potential solution is to use molecular singlet exciton fission to generate two electrons from each absorbed high-energy photon. We demonstrate that the long-standing challenge of coupling molecular excited states to silicon solar cells can be overcome using sequential charge transfer. Combining zinc phthalocyanine, aluminum oxide, and a shallow junction crystalline silicon microwire solar cell, the peak charge generation efficiency per photon absorbed in tetracene is (138 +- 6)%, comfortably surpassing the quantum efficiency limit for conventional silicon solar cells and establishing a new, scalable approach to low cost, high efficiency photovoltaics., Comment: 34 pages, 14 figures

Published
2024

3. Closed Loop Superparamagnetic Tunnel Junctions for Reliable True Randomness and Generative Artificial Intelligence

Author

Koh, Dooyong, Wang, Qiuyuan, McGoldrick, Brooke C., Chou, Chung-Tao, Liu, Luqiao, and Baldo, Marc A.

Subjects
Condensed Matter - Materials Science, Computer Science - Emerging Technologies
Abstract

Physical devices exhibiting stochastic functions with low energy consumption and high device density have the potential to enable complex probability-based computing algorithms, accelerate machine learning tasks, and enhance hardware security. Recently, superparamagnetic tunnel junctions (sMTJs) have been widely explored for such purposes, leading to the development of sMTJ-based systems; however, the reliance on nanoscale ferromagnets limits scalability and reliability, making sMTJs sensitive to external perturbations and prone to significant device variations. Here, we present an experimental demonstration of closed loop three-terminal sMTJs as reliable and potentially scalable sources of true randomness in the field-free regime. By leveraging dual-current controllability and incorporating feedback, we stabilize the switching operation of superparamagnets and reach cryptographic-quality random bitstreams. The realization of controllable and robust true random sMTJs underpin a general hardware platform for computing schemes exploiting the stochasticity in the physical world, as demonstrated by the generative artificial intelligence example in our experiment.

Published
2024

10. Magnetic domain wall based synaptic and activation function generator for neuromorphic accelerators

Author

Siddiqui, Saima A, Dutta, Sumit, Tang, Astera, Liu, Luqiao, Ross, Caroline A, and Baldo, Marc A

Subjects
Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Mesoscale and Nanoscale Physics, Computer Science - Emerging Technologies
Abstract

Magnetic domain walls are information tokens in both logic and memory devices, and hold particular interest in applications such as neuromorphic accelerators that combine logic in memory. Here, we show that devices based on the electrical manipulation of magnetic domain walls are capable of implementing linear, as well as programmable nonlinear, functions. Unlike other approaches, domain-wall-based devices are ideal for application to both synaptic weight generators and thresholding in deep neural networks. Prototype micrometer-size devices operate with 8 ns current pulses and the energy consumption required for weight modulation is < 16 pJ. Both speed and energy consumption compare favorably to other synaptic nonvolatile devices, with the expected energy dissipation for scaled 20 nm devices close to that of biological neurons., Comment: 24 pages, 5 figures

Published
2019
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11. Triplet-sensitization by lead halide perovskite thin films for near-infrared-to-visible upconversion

Author

Nienhaus, Lea, Correa-Baena, Juan-Pablo, Wieghold, Sarah, Einzinger, Markus, Lin, Ting-An, Shulenberger, Katherine E., Klein, Nathan D., Wu, Mengfei, Bulovic, Vladimir, Buonassisi, Tonio, Baldo, Marc A., and Bawendi, Moungi G.

Subjects
Physics - Applied Physics
Abstract

Lead halide-based perovskite thin films have attracted great attention due to the explosive increase in perovskite solar cell efficiencies. The same optoelectronic properties that make perovskites ideal absorber materials in solar cells are also beneficial in other light-harvesting applications and make them prime candidates as triplet sensitizers in upconversion via triplet-triplet annihilation in rubrene. In this contribution, we take advantage of long carrier lifetimes and carrier diffusion lengths in perovskite thin films, their high absorption cross sections throughout the visible spectrum, as well as the strong spin-orbit coupling owing to the abundance of heavy atoms to sensitize the upconverter rubrene. Employing bulk perovskite thin films as the absorber layer and spin-mixer in inorganic/organic heterojunction upconversion devices allows us to forego the additional tunneling barrier owing from the passivating ligands required for colloidal sensitizers. Our bilayer device exhibits an upconversion efficiency in excess of 3% under 785 nm illumination.

Published
2019

13. Designing a Broadband Pump for High-Quality Micro-Lasers via Modified Net Radiation Method

Author

Nechayev, Sergey, Reusswig, Philip D., Baldo, Marc A., and Rotschild, Carmel

Subjects
Physics - Optics
Abstract

High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of incoherent radiation between cascade sensitizer and laser gain media. Our model is based on linear equations of the modified net radiation method and is therefore robust, fast converging and has low complexity. We apply this formalism to compute the optimal parameters of low-threshold solar-pumped lasers. It is revealed that the interplay between the absorption and self-absorption of such lasers defines the optimal pump absorption below the maximal value, which is in contrast to conventional lasers for which full pump absorption is desired. Numerical results are compared to experimental data on a sensitized Nd:YAG cavity, and quantitative agreement with theoretical models is found. Our work modularizes the gain and sensitizing components and paves the way for the optimal design of broadband-pumped high-quality micro-lasers and efficient solar-pumped lasers., Comment: Manuscript with supplementary

Published
2016
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14. Plexcitons: Dirac points and topological modes

Author

Yuen-Zhou, Joel, Saikin, Semion K., Zhu, Tony H., Onbasli, Mehmet C., Ross, Caroline A., Bulovic, Vladimir, and Baldo, Marc A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Plexcitons are polaritonic modes that result from the strong coupling between excitons and plasmons. We consider plexcitons emerging from the interaction of excitons in an organic molecular layer with surface plasmons in a metallic film. We predict the emergence of Dirac cones in the two-dimensional bandstructure of plexcitons due to the inherent alignment of the excitonic transitions in the organic layer. These Dirac cones may open up in energy by simultaneously interfacing the metal with a magneto-optical layer and subjecting the whole system to a perpendicular magnetic field. The resulting energy gap becomes populated with topologically protected one-way modes which travel at the interface of this plexcitonic system. Our theoretical proposal suggests that plexcitons are a convenient and simple platform for the exploration of exotic phases of matter as well as of novel ways to direct energy flow at the nanoscale.

Published
2015
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15. 360{\deg} Domain Walls: Stability, Magnetic Field and Electric Current Effects

Author

Zhang, Jinshuo, Siddiqui, Saima A., Ho, Pin, Currivan-Incorvia, Jean Anne, Tryputen, Larysa, Lage, Enno, Bono, David C., Baldo, Marc A., and Ross, Caroline A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The formation of 360{\deg} magnetic domain walls (360DWs) in Co and Ni80Fe20 thin film wires was demonstrated experimentally for different wire widths, by successively injecting two 180{\deg} domain walls (180DWs) into the wire. For narrow wires (less than 50 nm wide for Co), edge roughness prevented the combination of the 180DWs into a 360DW, and for wide wires (200 nm for Co) the 360DW collapsed, but over an intermediate range of wire widths, reproducible 360DW formation occurred. The annihilation and dissociation of 360DWs was demonstrated by applying a magnetic field parallel to the wire, showing that annihilation fields were several times higher than dissociation fields in agreement with micromagnetic modeling. The annihilation of a 360DW by current pulsing was demonstrated., Comment: 17 pages, 6 figures

Published
2015
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17. Room temperature triplet state spectroscopy of organic semiconductors

Author

Reineke, Sebastian and Baldo, Marc A.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Chemical Physics
Abstract

Organic light emitting devices and solar cells are machines that create, manipulate and destroy excited states in organic semiconductors. It is crucial to characterize these excited states, or excitons, to optimize device performance in applications like displays and solar energy harvesting. This is complicated if the excited state is a triplet because the electronic transition is dark with a vanishing oscillator strength. As a consequence, triplet state spectroscopy must usually be performed at cryogenic temperatures to reduce competition from non-radiative rates. Here, we control non-radiative rates by engineering a solid-state host matrix containing the target molecule, allowing the observation of phosphorescence at room temperature and alleviating constraints of cryogenic experiments. We test these techniques on a wide range of materials with functionalities spanning multi-exciton generation (singlet exciton fission), organic light emitting device host materials, and thermally activated delayed fluorescence type emitters. Control of non-radiative modes in the matrix surrounding a target molecule may also have broader applications in light emitting and photovoltaic devices., Comment: 27 pages, 6 figures

Published
2013
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18. Highly efficient, dual state emission from an organic semiconductor

Author

Reineke, Sebastian, Seidler, Nico, Yost, Shane R., Prins, Ferry, Tisdale, William A., and Baldo, Marc A.

Subjects
Condensed Matter - Materials Science
Abstract

We report highly efficient, simultaneous fluorescence and phosphorescence (74% yield) at room temperature from a single molecule ensemble of (BzP)PB dispersed into a polymer host. The slow phosphorescence (208 ms lifetime) is very efficient (50%) at room temperature and only possible because the non-radiative rate for the triplet state is extremely low. The ability of an organic molecule to function as an efficient dual state emitter at room temperature is unusual and opens new fields of applications including the use as broadband down-conversion emitters, optical sensors and attenuators, exciton probes, and spin-independent intermediates for F\"orster resonant energy transfer.

Published
2013
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22. Fiber draw synthesis

Author

Orf, Nicholas D., Shapira, Ofer, Sorin, Fabien, Danto, Sylvain, Baldo, Marc A., Joannopoulos, John D., and Fink, Yoel

Published
2011

23. Discovery of blue singlet exciton fission molecules via a high-throughput virtual screening and experimental approach.

Author

Perkinson, Collin F., Tabor, Daniel P., Einzinger, Markus, Sheberla, Dennis, Utzat, Hendrik, Lin, Ting-An, Congreve, Daniel N., Bawendi, Moungi G., Aspuru-Guzik, Alán, and Baldo, Marc A.

Subjects
ANTHRACENE derivatives, TIME-dependent density functional theory, SOLAR cell efficiency, EXCIMERS, SOLAR cells
Abstract

Singlet exciton fission is a mechanism that could potentially enable solar cells to surpass the Shockley-Queisser efficiency limit by converting single high-energy photons into two lower-energy triplet excitons with minimal thermalization loss. The ability to make use of singlet exciton fission to enhance solar cell efficiencies has been limited, however, by the sparsity of singlet fission materials with triplet energies above the bandgaps of common semiconductors such as Si and GaAs. Here, we employ a high-throughput virtual screening procedure to discover new organic singlet exciton fission candidate materials with high-energy (>1.4 eV) triplet excitons. After exploring a search space of 4482 molecules and screening them using time-dependent density functional theory, we identify 88 novel singlet exciton fission candidate materials based on anthracene derivatives. Subsequent purification and characterization of several of these candidates yield two new singlet exciton fission materials: 9,10-dicyanoanthracene (DCA) and 9,10-dichlorooctafluoroanthracene (DCOFA), with triplet energies of 1.54 eV and 1.51 eV, respectively. These materials are readily available and low-cost, making them interesting candidates for exothermic singlet exciton fission sensitization of solar cells. However, formation of triplet excitons in DCA and DCOFA is found to occur via hot singlet exciton fission with excitation energies above ∼3.64 eV, and prominent excimer formation in the solid state will need to be overcome in order to make DCA and DCOFA viable candidates for use in a practical device. [ABSTRACT FROM AUTHOR]

Published
2019
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24. Consensus statement: Standardized reporting of power-producing luminescent solar concentrator performance

Author

Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W.Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry R., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G.J.H.M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W.H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, Lunt, Richard R., Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W.Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry R., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G.J.H.M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W.H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, and Lunt, Richard R.

Abstract

Fair and meaningful device performance comparison among luminescent solar concentrator-photovoltaic (LSC-PV) reports cannot be realized without a general consensus on reporting standards in LSC-PV research. Therefore, it is imperative to adopt standardized characterization protocols for these emerging types of PV devices that are consistent with other PV devices. This commentary highlights several common limitations in LSC literature and summarizes the best practices moving forward to harmonize with standard PV reporting, considering the greater nuances present with LSC-PV. Based on these practices, a checklist of actionable items is provided to help standardize the characterization/reporting protocols and offer a set of baseline expectations for authors, reviewers, and editors. The general consensus combined with the checklist will ultimately guide LSC-PV research towards reliable and meaningful advances.

Published
2022

25. Consensus statement: Standardized reporting of power-producing luminescent solar concentrator performance

Author

Integration of Photovoltaic Solar Energy, Energy and Resources, Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W.Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry R., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G.J.H.M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W.H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, Lunt, Richard R., Integration of Photovoltaic Solar Energy, Energy and Resources, Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W.Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry R., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G.J.H.M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W.H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, and Lunt, Richard R.

Published
2022

26. Interfacial Trap‐Assisted Triplet Generation in Lead Halide Perovskite Sensitized Solid‐State Upconversion

Author

Wang, Lili, Yoo, Jason J., Lin, Ting‐An, Perkinson, Collin F., Lu, Yongli, Baldo, Marc A., Bawendi, Moungi G., Wang, Lili, Yoo, Jason J., Lin, Ting‐An, Perkinson, Collin F., Lu, Yongli, Baldo, Marc A., and Bawendi, Moungi G.

Abstract

Photon upconversion via triplet–triplet annihilation (TTA) has promise for overcoming the Shockley–Queisser limit for single-junction solar cells by allowing the utilization of sub-bandgap photons. Recently, bulk perovskites have been employed as sensitizers in solid-state upconversion devices to circumvent poor exciton diffusion in previous nanocrystal (NC)-sensitized devices. However, an in-depth understanding of the underlying photophysics of perovskite-sensitized triplet generation is still lacking due to the difficulty of precisely controlling interfacial properties of fully solution-processed devices. In this study, interfacial properties of upconversion devices are adjusted by a mild surface solvent treatment, specifically altering perovskite surface properties without perturbing the bulk perovskite. Thermal evaporation of the annihilator precludes further solvent contamination. Counterintuitively, devices with more interfacial traps show brighter upconversion. Approximately an order of magnitude difference in upconversion brightness is observed across different interfacial solvent treatments. Sequential charge transfer and interfacial trap-assisted triplet sensitization are demonstrated by comparing upconversion performance, transient photoluminescence dynamics, and magnetic field dependence of the devices. Incomplete triplet conversion from transferred charges and consequent triplet-charge annihilation (TCA) are also observed. The observations highlight the importance of interfacial control and provide guidance for further design and optimization of upconversion devices using perovskites or other semiconductors as sensitizers.

Published
2022

27. Dominance of Exciton Lifetime in the Stability of Phosphorescent Dyes

Author

Ha, Dong‐Gwang, Tiepelt, Jan, Fusella, Michael A., Weaver, Michael S., Brown, Julie J., Einzinger, Markus, Sherrott, Michelle C., Van Voorhis, Troy, Thompson, Nicholas J., Baldo, Marc A., Ha, Dong‐Gwang, Tiepelt, Jan, Fusella, Michael A., Weaver, Michael S., Brown, Julie J., Einzinger, Markus, Sherrott, Michelle C., Van Voorhis, Troy, Thompson, Nicholas J., and Baldo, Marc A.

Published
2022

28. Magnetic‐Field‐Switchable Laser via Optical Pumping of Rubrene

Author

Perkinson, Collin F., Einzinger, Markus, Finley, Joseph, Bawendi, Moungi G., Baldo, Marc A., Perkinson, Collin F., Einzinger, Markus, Finley, Joseph, Bawendi, Moungi G., and Baldo, Marc A.

Abstract

Volumetric optical imaging of magnetic fields is challenging with existing magneto-optical materials, motivating the search for dyes with strong magnetic field interactions, distinct emission spectra, and an ability to withstand high photon flux and incorporation within samples. Here, the magnetic field effect on singlet-exciton fission is exploited to demonstrate spatial imaging of magnetic fields in a thin film of rubrene. Doping rubrene with the high-quantum yield dye dibenzotetraphenylperiflanthene (DBP) is shown to enable optically pumped, slab waveguide lasing. This laser is magnetic-field-switchable: when operated just below the lasing threshold, application of a 0.4 T magnetic field switches the device between nonlasing and lasing modes, accompanied by an intensity modulation of +360%. This is thought to be the first demonstration of a magnetically switchable laser, as well as the largest magnetically induced change in emission brightness in a singlet-fission material to date. These results demonstrate that singlet-fission materials are promising materials for magnetic sensing applications and could inspire a new class of magneto-optical modulators.

Published
2022

29. 3D-Printed Self-Folding Electronics

Author

Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Sundaram, Subramanian, Kim, David Saerom, Baldo, Marc A, Hayward, Ryan C., Matusik, Wojciech, Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Sundaram, Subramanian, Kim, David Saerom, Baldo, Marc A, Hayward, Ryan C., and Matusik, Wojciech

Abstract

© 2017 American Chemical Society. Self-transforming structures are gaining prominence due to their general ability to adopt programmed shapes each tailored for specific functions. Composites that self-fold have so far relied on using the stimuli-responsive mechanisms focusing on reversible shape change. Integrating additional functions within these composites can rapidly enhance their practical applicability; however, this remains a challenging problem. Here, we demonstrate a method for spontaneous folding of three-dimensional (3D)-printed composites with embedded electronics at room temperature. The composite is printed using a multimaterial 3D-printing process with no external processing steps. Upon peeling from the print platform, the composite self-shapes itself using the residual forces resulting from polymer swelling during the layer-by-layer fabrication process. As a specific example, electrochromic elements are printed within the composite and can be electrically controlled through its folded legs. Our shape-transformation scheme provides a route to transform planar electronics into nonplanar geometries containing the overhangs. Integrating electronics within complex 3D shapes can enable new applications in sensing and robotics.

Published
2022

30. Large Increase in External Quantum Efficiency by Dihedral Angle Tuning in a Sky‐Blue Thermally Activated Delayed Fluorescence Emitter

Author

Massachusetts Institute of Technology. Department of Chemistry, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Huang, Wenliang, Einzinger, Markus, Maurano, Andrea, Zhu, Tianyu, Tiepelt, Jan, Yu, Chao, Chae, Hyun Sik, Van Voorhis, Troy, Baldo, Marc A., Buchwald, Stephen L., Massachusetts Institute of Technology. Department of Chemistry, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Huang, Wenliang, Einzinger, Markus, Maurano, Andrea, Zhu, Tianyu, Tiepelt, Jan, Yu, Chao, Chae, Hyun Sik, Van Voorhis, Troy, Baldo, Marc A., and Buchwald, Stephen L.

Published
2022

32. Magnetic‐Field‐Switchable Laser via Optical Pumping of Rubrene

Author

Perkinson, Collin F, Einzinger, Markus, Finley, Joseph, Bawendi, Moungi G, Baldo, Marc A, Perkinson, Collin F, Einzinger, Markus, Finley, Joseph, Bawendi, Moungi G, and Baldo, Marc A

Abstract

Volumetric optical imaging of magnetic fields is challenging with existing magneto-optical materials, motivating the search for dyes with strong magnetic field interactions, distinct emission spectra, and an ability to withstand high photon flux and incorporation within samples. Here, the magnetic field effect on singlet-exciton fission is exploited to demonstrate spatial imaging of magnetic fields in a thin film of rubrene. Doping rubrene with the high-quantum yield dye dibenzotetraphenylperiflanthene (DBP) is shown to enable optically pumped, slab waveguide lasing. This laser is magnetic-field-switchable: when operated just below the lasing threshold, application of a 0.4 T magnetic field switches the device between nonlasing and lasing modes, accompanied by an intensity modulation of +360%. This is thought to be the first demonstration of a magnetically switchable laser, as well as the largest magnetically induced change in emission brightness in a singlet-fission material to date. These results demonstrate that singlet-fission materials are promising materials for magnetic sensing applications and could inspire a new class of magneto-optical modulators.

Published
2022

33. Consensus statement: Standardized reporting of power-producing luminescent solar concentrator performance

Author

Yang, C, Atwater, H, Baldo, M, Baran, D, Barile, C, Barr, M, Bates, M, Bawendi, M, Bergren, M, Borhan, B, Brabec, C, Brovelli, S, Bulović, V, Ceroni, P, Debije, M, Delgado-Sanchez, J, Dong, W, Duxbury, P, Evans, R, Forrest, S, Gamelin, D, Giebink, N, Gong, X, Griffini, G, Guo, F, Herrera, C, Ho-Baillie, A, Holmes, R, Hong, S, Kirchartz, T, Levine, B, Li, H, Li, Y, Liu, D, Loi, M, Luscombe, C, Makarov, N, Mateen, F, Mazzaro, R, Mcdaniel, H, Mcgehee, M, Meinardi, F, Menéndez-Velázquez, A, Min, J, Mitzi, D, Moemeni, M, Moon, J, Nattestad, A, Nazeeruddin, M, Nogueira, A, Paetzold, U, Patrick, D, Pucci, A, Rand, B, Reichmanis, E, Richards, B, Roncali, J, Rosei, F, Schmidt, T, So, F, Tu, C, Vahdani, A, van Sark, W, Verduzco, R, Vomiero, A, Wong, W, Wu, K, Yip, H, Zhang, X, Zhao, H, Lunt, R, Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W. Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry P., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G. J. H. M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W. H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, Lunt, Richard R., Yang, C, Atwater, H, Baldo, M, Baran, D, Barile, C, Barr, M, Bates, M, Bawendi, M, Bergren, M, Borhan, B, Brabec, C, Brovelli, S, Bulović, V, Ceroni, P, Debije, M, Delgado-Sanchez, J, Dong, W, Duxbury, P, Evans, R, Forrest, S, Gamelin, D, Giebink, N, Gong, X, Griffini, G, Guo, F, Herrera, C, Ho-Baillie, A, Holmes, R, Hong, S, Kirchartz, T, Levine, B, Li, H, Li, Y, Liu, D, Loi, M, Luscombe, C, Makarov, N, Mateen, F, Mazzaro, R, Mcdaniel, H, Mcgehee, M, Meinardi, F, Menéndez-Velázquez, A, Min, J, Mitzi, D, Moemeni, M, Moon, J, Nattestad, A, Nazeeruddin, M, Nogueira, A, Paetzold, U, Patrick, D, Pucci, A, Rand, B, Reichmanis, E, Richards, B, Roncali, J, Rosei, F, Schmidt, T, So, F, Tu, C, Vahdani, A, van Sark, W, Verduzco, R, Vomiero, A, Wong, W, Wu, K, Yip, H, Zhang, X, Zhao, H, Lunt, R, Yang, Chenchen, Atwater, Harry A., Baldo, Marc A., Baran, Derya, Barile, Christopher J., Barr, Miles C., Bates, Matthew, Bawendi, Moungi G., Bergren, Matthew R., Borhan, Babak, Brabec, Christoph J., Brovelli, Sergio, Bulović, Vladimir, Ceroni, Paola, Debije, Michael G., Delgado-Sanchez, Jose-Maria, Dong, Wen-Ji, Duxbury, Phillip M., Evans, Rachel C., Forrest, Stephen R., Gamelin, Daniel R., Giebink, Noel C., Gong, Xiao, Griffini, Gianmarco, Guo, Fei, Herrera, Christopher K., Ho-Baillie, Anita W. Y., Holmes, Russell J., Hong, Sung-Kyu, Kirchartz, Thomas, Levine, Benjamin G., Li, Hongbo, Li, Yilin, Liu, Dianyi, Loi, Maria A., Luscombe, Christine K., Makarov, Nikolay S., Mateen, Fahad, Mazzaro, Raffaello, McDaniel, Hunter, McGehee, Michael D., Meinardi, Francesco, Menéndez-Velázquez, Amador, Min, Jie, Mitzi, David B., Moemeni, Mehdi, Moon, Jun Hyuk, Nattestad, Andrew, Nazeeruddin, Mohammad K., Nogueira, Ana F., Paetzold, Ulrich W., Patrick, David L., Pucci, Andrea, Rand, Barry P., Reichmanis, Elsa, Richards, Bryce S., Roncali, Jean, Rosei, Federico, Schmidt, Timothy W., So, Franky, Tu, Chang-Ching, Vahdani, Aria, van Sark, Wilfried G. J. H. M., Verduzco, Rafael, Vomiero, Alberto, Wong, Wallace W. H., Wu, Kaifeng, Yip, Hin-Lap, Zhang, Xiaowei, Zhao, Haiguang, and Lunt, Richard R.

Abstract

Fair and meaningful device performance comparison among luminescent solar concentrator-photovoltaic (LSC-PV) reports cannot be realized without a general consensus on reporting standards in LSC-PV research. Therefore, it is imperative to adopt standardized characterization protocols for these emerging types of PV devices that are consistent with other PV devices. This commentary highlights several common limitations in LSC literature and summarizes the best practices moving forward to harmonize with standard PV reporting, considering the greater nuances present with LSC-PV. Based on these practices, a checklist of actionable items is provided to help standardize the characterization/reporting protocols and offer a set of baseline expectations for authors, reviewers, and editors. The general consensus combined with the checklist will ultimately guide LSC-PV research towards reliable and meaningful advances.

Published
2022

35. Introduction to Nanoelectronics

Author

Baldo, Marc

Subjects
Science
Abstract

Traditionally, progress in electronics has been driven by miniaturization. But as electronic devices approach the molecular scale, classical models for device behavior must be abandoned. To prepare for the next generation of electronic devices, this class teaches the theory of current, voltage and resistance from atoms up. To describe electrons at the nanoscale, we will begin with an introduction to the principles of quantum mechanics, including quantization, the wave-particle duality, wavefunctions and Schrödinger's equation. Then we will consider the electronic properties of molecules, carbon nanotubes and crystals, including energy band formation and the origin of metals, insulators and semiconductors. Electron conduction will be taught beginning with ballistic transport and concluding with a derivation of Ohm's law. We will then compare ballistic to bulk MOSFETs. The class will conclude with a discussion of possible fundamental limits to computation.

Published
2011

36. Consensus statement: Standardized reporting of power-producing luminescent solar concentrator performance

Author

Yang, Chenchen, primary, Atwater, Harry A., additional, Baldo, Marc A., additional, Baran, Derya, additional, Barile, Christopher J., additional, Barr, Miles C., additional, Bates, Matthew, additional, Bawendi, Moungi G., additional, Bergren, Matthew R., additional, Borhan, Babak, additional, Brabec, Christoph J., additional, Brovelli, Sergio, additional, Bulović, Vladimir, additional, Ceroni, Paola, additional, Debije, Michael G., additional, Delgado-Sanchez, Jose-Maria, additional, Dong, Wen-Ji, additional, Duxbury, Phillip M., additional, Evans, Rachel C., additional, Forrest, Stephen R., additional, Gamelin, Daniel R., additional, Giebink, Noel C., additional, Gong, Xiao, additional, Griffini, Gianmarco, additional, Guo, Fei, additional, Herrera, Christopher K., additional, Ho-Baillie, Anita W.Y., additional, Holmes, Russell J., additional, Hong, Sung-Kyu, additional, Kirchartz, Thomas, additional, Levine, Benjamin G., additional, Li, Hongbo, additional, Li, Yilin, additional, Liu, Dianyi, additional, Loi, Maria A., additional, Luscombe, Christine K., additional, Makarov, Nikolay S., additional, Mateen, Fahad, additional, Mazzaro, Raffaello, additional, McDaniel, Hunter, additional, McGehee, Michael D., additional, Meinardi, Francesco, additional, Menéndez-Velázquez, Amador, additional, Min, Jie, additional, Mitzi, David B., additional, Moemeni, Mehdi, additional, Moon, Jun Hyuk, additional, Nattestad, Andrew, additional, Nazeeruddin, Mohammad K., additional, Nogueira, Ana F., additional, Paetzold, Ulrich W., additional, Patrick, David L., additional, Pucci, Andrea, additional, Rand, Barry P., additional, Reichmanis, Elsa, additional, Richards, Bryce S., additional, Roncali, Jean, additional, Rosei, Federico, additional, Schmidt, Timothy W., additional, So, Franky, additional, Tu, Chang-Ching, additional, Vahdani, Aria, additional, van Sark, Wilfried G.J.H.M., additional, Verduzco, Rafael, additional, Vomiero, Alberto, additional, Wong, Wallace W.H., additional, Wu, Kaifeng, additional, Yip, Hin-Lap, additional, Zhang, Xiaowei, additional, Zhao, Haiguang, additional, and Lunt, Richard R., additional

Published
2022
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40. Guaranteed global optimization of thin-film optical systems

Author

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mathematics, Azunre, Paul, Jean, Joel, Rotschild, Carmel, Bulovic, Vladimir, Johnson, Steven G, Baldo, Marc A, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mathematics, Azunre, Paul, Jean, Joel, Rotschild, Carmel, Bulovic, Vladimir, Johnson, Steven G, and Baldo, Marc A

Abstract

© 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft. A parallel deterministic global optimization algorithm for thin-film multilayer optical coatings is developed. This algorithm enables locating a global solution to an optimization problem in this class to within a user-specified tolerance. More specifically, the algorithm is a parallel branch-And-bound method with applicable bounds on the merit function computed using Taylor models. This study is the first one, to the best of our knowledge, to attempt guaranteed global optimization of this important class of problems, thereby providing an overview and an assessment of the current state of such techniques in this domain. As a proof of concept on a small scale, the method is illustrated numerically and experimentally in the context of antireflection coatings for silicon solar cells-we design and fabricate a three-layer dielectric stack on silicon that exhibits an average reflectance of (2.53 0.10)%, weighted over a broad range of incident angles and the solar spectrum. The practicality of our approach is assessed by comparing its computational cost relative to traditional stochastic global optimization techniques which provide no guarantees on their solutions. While our method is observed to be significantly more computationally expensive, we demonstrate via our proof of concept that it is already feasible to optimize sufficiently simple practical problems at a reasonable cost, given the current accessibility of cloud computing resources. Ongoing advances in distributed computing are likely to bring more design problems within the reach of deterministic global optimization methods, yielding rigorous guaranteed solutions in the presence of practical manufacturing constraints.

Published
2021

41. 3D-Printed Self-Folding Electronics

Author

Sundaram, Subramanian, Kim, David S, Baldo, Marc A, Hayward, Ryan C, Matusik, Wojciech, Sundaram, Subramanian, Kim, David S, Baldo, Marc A, Hayward, Ryan C, and Matusik, Wojciech

Abstract

© 2017 American Chemical Society. Self-transforming structures are gaining prominence due to their general ability to adopt programmed shapes each tailored for specific functions. Composites that self-fold have so far relied on using the stimuli-responsive mechanisms focusing on reversible shape change. Integrating additional functions within these composites can rapidly enhance their practical applicability; however, this remains a challenging problem. Here, we demonstrate a method for spontaneous folding of three-dimensional (3D)-printed composites with embedded electronics at room temperature. The composite is printed using a multimaterial 3D-printing process with no external processing steps. Upon peeling from the print platform, the composite self-shapes itself using the residual forces resulting from polymer swelling during the layer-by-layer fabrication process. As a specific example, electrochromic elements are printed within the composite and can be electrically controlled through its folded legs. Our shape-transformation scheme provides a route to transform planar electronics into nonplanar geometries containing the overhangs. Integrating electronics within complex 3D shapes can enable new applications in sensing and robotics.

Published
2021

42. Sensitization of silicon by singlet exciton fission in tetracene

Author

Massachusetts Institute of Technology. Research Laboratory of Electronics, Massachusetts Institute of Technology. Department of Mechanical Engineering, Massachusetts Institute of Technology. Department of Chemistry, Wu, Tony C, Einzinger, Markus, Kompalla, Julia, Smith, Hannah L., Perkinson, Collin Fisher, Nienhaus, Lea, Wieghold, Sarah, Congreve, Daniel Norbert, Thompson, Nicholas J., Kahn, Antoine, Bawendi, Moungi G, Baldo, Marc A, Massachusetts Institute of Technology. Research Laboratory of Electronics, Massachusetts Institute of Technology. Department of Mechanical Engineering, Massachusetts Institute of Technology. Department of Chemistry, Wu, Tony C, Einzinger, Markus, Kompalla, Julia, Smith, Hannah L., Perkinson, Collin Fisher, Nienhaus, Lea, Wieghold, Sarah, Congreve, Daniel Norbert, Thompson, Nicholas J., Kahn, Antoine, Bawendi, Moungi G, and Baldo, Marc A

Abstract

Singlet fission can split a high energy singlet exciton and generate two lower energy triplet excitons. This process has shown near 200 percent triplet exciton yield. Sensitizing solar cells with singlet fission material, it can potentially increase the power conversion efficiency limit from 29 percent to 35 percent. Singlet fission in the tetracene is known to be efficient, and the energy of the triplet excitons are energetically matched to the silicon bandgap. In this work, we designed an optical measurement with an external magnetic field to determine the efficiencies of triplet exciton transfer from tetracene to silicon. Using this method, we have found that a passivation layer of 8 angstroms of hafnium oxynitride on silicon allows efficient triplet exciton transfer around 133 percent.

Published
2021

45. Large Single Crystals of Two-Dimensional π-Conjugated Metal–Organic Frameworks via Biphasic Solution-Solid Growth

Author

Ha, Dong-Gwang, primary, Rezaee, Mehdi, additional, Han, Yimo, additional, Siddiqui, Saima A., additional, Day, Robert W., additional, Xie, Lilia S., additional, Modtland, Brian J., additional, Muller, David A., additional, Kong, Jing, additional, Kim, Philip, additional, Dincă, Mircea, additional, and Baldo, Marc A., additional

Published
2020
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46. Sensitization of silicon by singlet exciton fission in tetracene

Author

Wu, Tony C., primary, Einzinger, Markus, additional, Kompalla, Julia, additional, Smith, Hannah L., additional, Perkinson, Collin F., additional, Nienhaus, Lea, additional, Wieghold, Sarah, additional, Congreve, Daniel N., additional, Thompson, Nicholas, additional, Kahn, Antoine, additional, Bawendi, Moungi G., additional, and Baldo, Marc A., additional

Published
2020
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49. Electroluminescence mechanisms in organic light emitting devices employing a europium chelate doped in a wide energy gap bipolar conducting host

Author

Adachi, Chihaya, Baldo, Marc A., and Forrest, Stephen R.

Subjects
Chelates -- Optical properties, Europium -- Optical properties, Electroluminescence -- Analysis, Physics
Abstract

The electroluminescence mechanisms of the lanthanide complex Eu(TTA)phen doped into CBP are investigated. The results suggest that lanthanide complexes face the same limitations as other metallorganic phosphors via triplet-metal ion transitions.

Published
2000

50. Magnetic domain wall based synaptic and activation function generator for neuromorphic accelerators

Author

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Materials Science and Engineering, Siddiqui, Saima Afroz, Dutta, Sumit, Tang, Astera S., Liu, Luqiao, Ross, Caroline A., Baldo, Marc A, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Materials Science and Engineering, Siddiqui, Saima Afroz, Dutta, Sumit, Tang, Astera S., Liu, Luqiao, Ross, Caroline A., and Baldo, Marc A

Abstract

Magnetic domain walls are information tokens in both logic and memory devices and hold particular interest in applications such as neuromorphic accelerators that combine logic in memory. Here, we show that devices based on the electrical manipulation of magnetic domain walls are capable of implementing linear, as well as programmable nonlinear, functions. Unlike other approaches, domain-wall-based devices are ideal for application to both synaptic weight generators and thresholding in deep neural networks. Prototype micrometer-size devices operate with 8 ns current pulses and the energy consumption required for weight modulation is ≤16 pJ. Both speed and energy consumption compare favorably to other synaptic nonvolatile devices, with the expected energy dissipation for scaled 20 nm devices close to that of biological neurons., National Science Foundation (U.S.) (Award 1639921)

Published
2020

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