28 results on '"Yan, Qing"'
Search Results
2. Spectrally stable blue electroluminescence of mixed-halide perovskite light-emitting diodes featuring ion migration inhibition
- Author
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Wang, Yuhan, Tian, Yu, Luo, Yu-Xin, Yang, Jian-Ming, Cheng, Li-Peng, Wu, Hai-Yan, Tang, Jian-Xin, and Li, Yan-Qing
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- 2020
- Full Text
- View/download PDF
3. The role of gap states on energy level alignment at an α-NPD/HAT(CN)6 charge generation interface
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Yang, Jin-Peng, Bussolotti, Fabio, Li, Yan-Qing, Zeng, Xiang-Hua, Kera, Satoshi, Tang, Jian-Xin, and Ueno, Nobuo
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- 2015
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- View/download PDF
4. Annealing-induced phase separation in small-molecular bulk heterojunctions
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Wei, Huai-Xin, Li, Yan-Qing, Chen, Xiang-Yu, Lee, Chun-Sing, and Tang, Jian-Xin
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- 2014
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5. Understanding the effect of N2200 on performance of J71: ITIC bulk heterojunction in ternary non-fullerene solar cells
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Danqin Li, Qinye Bao, Jinqiu Xu, Yue-Xing Zhang, Feng Liu, Shaobing Xiong, Ming Jan, Bo Li, Mats Fahlman, Zhiquan Wang, Chun-Gang Duan, Yan-Qing Li, Jian-Xin Tang, and Xuewen Guo
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Materials science ,Organic solar cell ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Polymer solar cell ,Biomaterials ,Materials Chemistry ,Annan elektroteknik och elektronik ,Electrical and Electronic Engineering ,Other Electrical Engineering, Electronic Engineering, Information Engineering ,business.industry ,Open-circuit voltage ,Energy conversion efficiency ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Acceptor ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Active layer ,Optoelectronics ,0210 nano-technology ,business ,Ternary operation ,Short circuit ,None-fullerene ,Interface ,Charge recombination ,Efficiency ,Ternary organic solar cells - Abstract
None-fullerene solar cells with ternary architecture have attracted much attention because it is an effective approach for boosting the device power conversion efficiency. Here, the crystalline polymer N2200 as the third component is integrated into J71: ITIC bulk heterojunction. A series of characterizations indicate that N2200 could increase photo-harvesting, balanced hole and electron mobilities, enhanced exciton dissociation, and suppressed charge recombination, which result in the comprehensive improvement of open circuit voltage, short circuit current and fill factor in the device. Moreover, after introduction of N2200, the morphology of the ternary active layer is optimized, and the film crystallinity is improved. This work demonstrates that adding a small quantity of high crystallization acceptor into non-fullerene donor: acceptor mixture is a promising strategy toward developing high-performance organic solar cells. Funding Agencies|National Science Foundation of China [11604099, 21875067, 51873138, 51811530011]; Shanghai Rising -Star [19QA1403100]; Shanghai Science and Technology Innovation Action Plan [17JC1402500]; National Key Project for Basic Research of China [2017YFA0303403]; Swedish Research Council [2016-05498]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; STINT grant [CH2017-7163]
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- 2019
6. The modified PEDOT:PSS as cathode interfacial layer for scalable organic solar cells
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Qi Sun, Rui-Peng Xu, Chi Li, Jian-Xin Tang, Zhongmin Bao, Yan-Qing Li, Jiawei Zheng, Jing-De Chen, and Zhongzhi Xie
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Materials science ,Organic solar cell ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Effective nuclear charge ,law.invention ,Biomaterials ,PEDOT:PSS ,law ,Materials Chemistry ,Work function ,Electrical and Electronic Engineering ,Applied Physics ,business.industry ,Doping ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Cathode ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Anode ,02 Physical Sciences, 03 Chemical Sciences, 09 Engineering ,Optoelectronics ,0210 nano-technology ,business ,Layer (electronics) - Abstract
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is extensively used as an anode interfacial layer in optoelectronic devices due to its excellent hole-transporting properties and high work function (ϕF). In this study, we propose a simple and cost-effective method to controllably tune the ϕF of PEDOT:PSS from 5.1 eV to 3.95 eV by doping the polyethylenimine ethoxylated (PEIE). The PEIE-doped PEDOT:PSS films can function as a cathode interfacial layer in organic solar cells, showing the comparable performance to a conventional ZnO-based cell. The photoelectric characteristics, surface morphology, and electron transport ability of PEIE-doped PEDOT:PSS films were systematically investigated to elucidate the physical nature of the conversion from hole transport to electron transport. This strategy provides an effective charge transport layer for optoelectronic devices, which is suitable for large-scale, industrial applications.
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- 2019
7. Unraveling the light-induced degradation mechanism of CH3NH3PbI3 perovskite films
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Qiu-Ming Hong, Rui-Peng Xu, Yan-Qing Li, Jian-Xin Tang, and Tengyu Jin
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Diffraction ,Materials science ,Scanning electron microscope ,Binding energy ,Halide ,02 engineering and technology ,General Chemistry ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,medicine.disease_cause ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,X-ray photoelectron spectroscopy ,Chemical engineering ,Materials Chemistry ,medicine ,Electrical and Electronic Engineering ,0210 nano-technology ,Ultraviolet ,Perovskite (structure) - Abstract
While metal halide hybrid perovskite solar cells (PeSCs) are remarkably efficient, the rapid and undesirable degradation limit their practical applications for renewable energy sources. Herein, the evolution of perovskite decomposition under white light illumination has been investigated under the ultrahigh vacuum conditions, which can effectively rule out the influence of other factors such as oxygen or moisture. The chemical composition, electronic structure, surface morphology, and crystal structure of CH3NH3PbI3 perovskite films have been systematically characterized by X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS), scanning electron microscopy, and X-ray diffraction techniques. The surface roughening with cracks and defects occurs in CH3NH3PbI3 perovskite films after a short-time white-light illumination in ultrahigh vacuum. In situ compositional analysis reveals the decomposition of the perovskite films with the appearance of metallic Pb feature, which is accompanied with the energy level shift towards higher binding energy during the illumination process. However, the decomposition rate is decreased and becomes saturated after exposed to light illumination for 24 h. These findings provide a direct evidence that CH3NH3PbI3 perovskite is photosensitive, and a light-induced degradation mechanism is proposed.
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- 2019
8. Efficient solution-processed red organic light-emitting diode based on an electron-donating building block of pyrrolo[3,2-b]pyrrole
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Xiaohong Zhang, Yan-Qing Du, Chi Zhang, Cai-Jun Zheng, Yi Yuan, Kai Wang, Huan Liu, Ming Zhang, Yu Zhou, and Jun Ye
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Materials science ,Fluorophore ,02 engineering and technology ,General Chemistry ,Electron ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Block (periodic table) ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,OLED ,Moiety ,Quantum efficiency ,Electrical and Electronic Engineering ,0210 nano-technology ,Pyrrole ,Diode - Abstract
An electron-rich moiety, pyrrolo[3,2-b]pyrrole, has been used as a new donor block in organic lighting-emitting diodes (OLEDs). Combined with a strong electron-withdrawing group of 2,1,3-benzothiadiazole, a novel red fluorophore BTZPP was synthesized. The solution-processed red-emitting device based on BTZPP showed encouraging performances with external quantum efficiency of up to 3.4%. This evidently indicates that the pyrrolo[3,2-b]pyrrole group can be a promising electron-donating moiety for enriching the material types and promoting the development of OLEDs.
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- 2019
9. Theoretical perspective to light outcoupling and management in perovskite light-emitting diodes
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Yan-Qing Li, Shuai-Shuai Meng, and Jian-Xin Tang
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Materials science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Biomaterials ,Stack (abstract data type) ,law ,Materials Chemistry ,Electrical and Electronic Engineering ,Perovskite (structure) ,Common emitter ,Diode ,business.industry ,General Chemistry ,Material Design ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Optoelectronics ,Photonics ,0210 nano-technology ,business ,Refractive index ,Light-emitting diode - Abstract
Despite the rapid development of high-efficiency perovskite light-emitting diodes (PeLEDs) via material design and morphology control, a comprehensive evaluation of the power loss among various optical modes has seldom been conducted for the precise design of device architectures. Here, a quantitative analysis of light outcoupling efficiency (ηout) of PeLEDs is presented with the theoretical simulations by taking into account the key factors of refractive index and film thickness of various functional layers, and the emitter dipole orientation. For a planar PeLED, a rational design to enhance the ηout is predicted by constructing multilayer stack in series of transparent electrode/high-index transport layer/perovskite emitter/low-index transport layer/reflective electrode. Furthermore, the role of photonic structures on the outcoupling management is explored, and the potential of a substantial increase in ηout is demonstrated with an enhancement factor of over 1.75 by implementing a moth-eye nanostructure into the emitter. We anticipate that the findings shown here will provide the design guidelines for the optical optimization of PeLEDs.
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- 2018
10. Toward ultra-low reflectance semi-transparent organic photovoltaic cells with biomimetic nanostructured transparent electrode
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Wei Li, Yan-Qing Li, Yue-Xing Zhang, Jian-Xin Tang, Jing-De Chen, Jiawei Zheng, Yongjie Wang, Qi Sun, Wanli Ma, Xufeng Ling, and Chen Gao
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Photocurrent ,Materials science ,business.industry ,Energy conversion efficiency ,Photovoltaic system ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Color rendering index ,Electrode ,Materials Chemistry ,Reflection (physics) ,Transmittance ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business - Abstract
Semi-transparent organic photovoltaic cells (STOPVs) hold the great potential as a solar conversion source installed on the glass curtain walls. The cell performance of STOPVs is to some extent balanced among the absorption, transmission and reflection of the incident solar radiation. For the practical application with a defined transparency, the efficiency of STOPVs can be optimized by maximizing the light absorption as well as minimizing the reflection that contribute to the light pollution. Herein, a low-reflectance STOPV is presented with relatively high efficiency, high transmittance, and suitable color rendering property. A 15.9% increase in photocurrent and a 28% decrease in reflection are realized with the implementation of biomimetic moth-eye nanostructures into the dielectric-metal-dielectric transparent electrodes. For an optimized PTB7:PC71BM-based STOPV on flexible plastic substrate, the average transmittance in the visible region is kept at 46.1% and the average reflectance is reduced to 10.3%, leading a power conversion efficiency of 3.4%. The pathway described here is promising for opening up opportunities of reliable STOPVs towards the future commercial applications.
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- 2018
11. Novel small-molecule zwitterionic electrolyte with ultralow work function as cathode modifier for inverted polymer solar cells
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Xianjie Liu, Yan-Qing Li, Zhiquan Wang, Slawomir Braun, Yue-Xing Zhang, Qinye Bao, Mats Fahlman, Bo Li, Chun-Gang Duan, Jian-Xin Tang, Xuewen Guo, and Junfeng Fang
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Materials science ,Organic solar cell ,02 engineering and technology ,General Chemistry ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Polymer solar cell ,Cathode ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,Organic semiconductor ,Chemical engineering ,law ,Electrode ,Solar cell ,Materials Chemistry ,Work function ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
Interfacial compatibility between the electrode and organic semiconductor plays a critical role in controlling the charge transport and hence efficiency of organic solar cell. Here, we introduce a novel small-molecule zwitterionic electrolyte (S1) combined with ZnO as electron transporting interlayer employed for the inverted PTB7:PC71BM bulk heterojunction solar cell. The resulting device with the S1/ZnO stacked interlayer achieves a high PCE of 8.59%, obtaining a 16.2% improvement over the control device performance of 7.4% without the S1 attributed to the significant increased short-circuit current density and fill factor. The interfacial properties are investigated. It is found that the S1/ZnO interlayer possess an ultralow work function of 3.6 eV, which originates from the interfacial double dipole step induced by the zwitterionic side chain electrostatic realignment at interface. The S1/ZnO interlayer exhibits the excellent charge extraction ability, suppresses the charge recombination loss and decreases the series resistance at the active layer/electrode contact.
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- 2018
12. Novel D-σ-A type thermally activated delayed fluorescence emitters with C–S σ bond for the orange-red OLEDs
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Feng-Ming Xie, Ying-Yuan Hu, Yan-Qing Li, Fei-xiang Huang, Xin Zhao, Jian-Xin Tang, Ping Wu, Huai-Xin Wei, and Hao-ze Li
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Orange (colour) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,Sulfur ,Fluorescence ,Acceptor ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry ,Materials Chemistry ,OLED ,Fluorescent materials ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
Three D-σ-A type thermally activated delayed fluorescent materials (TADF), AQ-S-Cz, AQ-S-DPA and AQ-S-DMAC, with sulfur atom connect donors and acceptor, were designed and synthesized. All of the emitters exhibit small ΔEST (
- Published
- 2021
13. The electro-optic performance and photovoltaic effect of organic devices based on cesium carbonate/Al/molybdenum trioxide intermediate connector
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Jinjiang Wang, Qingdong Ou, Jian-Xin Tang, Liezun Chen, Dengyu Zhang, Yan-Hong Deng, and Yan-Qing Li
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,Photovoltaic effect ,Photon energy ,01 natural sciences ,Spectral line ,Molybdenum trioxide ,Biomaterials ,chemistry.chemical_compound ,0103 physical sciences ,Materials Chemistry ,OLED ,Electrical and Electronic Engineering ,Diode ,010302 applied physics ,Tandem ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,chemistry ,Caesium ,Optoelectronics ,0210 nano-technology ,business - Abstract
An intermediate connector of Cs 2 CO 3 /Al/MoO 3 used in tandem organic light-emitting diodes (OLEDs) was investigated in this work. Here, an ultrathin Cs 2 CO 3 /Al was used as an electron-injection layer (EIL) from MoO 3 to the adjacent electron transporting layer (ETL). To verify the function of this intermediate connector, the device performances were evaluated through current density-voltage-luminance characteristics, current density-efficiency curves, and EL spectra. Additionally, the effect of photon energy on carriers behavior in the Cs 2 CO 3 /Al/MoO 3 connector is also estimated. The electrical properties and EL spectra of tandem OLEDs show that the Cs 2 CO 3 /Al/MoO 3 can function well for charge generation and transport, and the current density-voltage curves of Cs 2 CO 3 /Al/MoO 3 based special multilayer device shows the photovoltaic effect as a photovoltaic cell.
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- 2017
14. Fermi-level pinning appears upon weak electrode-organic contact without gap states: A universal phenomenon
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Yan-Qing Li, Wen-Qing Wang, Jinpeng Yang, Lin-Tai Shang, Fabio Bussolotti, Xianghua Zeng, Jian-Xin Tang, Nobuo Ueno, Satoshi Kera, and Liwen Cheng
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Materials science ,Band gap ,02 engineering and technology ,01 natural sciences ,Biomaterials ,Pentacene ,chemistry.chemical_compound ,symbols.namesake ,0103 physical sciences ,Materials Chemistry ,Electrical and Electronic Engineering ,010306 general physics ,HOMO/LUMO ,Condensed matter physics ,business.industry ,Fermi level ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Organic semiconductor ,Semiconductor ,chemistry ,Electrode ,symbols ,0210 nano-technology ,business ,Ultraviolet photoelectron spectroscopy - Abstract
We report computational and experimental studies (i) on the Fermi level (EF) pinning phenomena in weakly interacting electrode-organic semiconductor systems with pentacene, N, N-Di(naphthalene-l-yl)-N, N’-diphenyl-benzidine (α-NPD) and Poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT)], and (ii) to elucidate a common reason of the pinning phenomena which have been widely observed for various organic materials on inert electrode surfaces. For (i), the computed results on the electrode-dependence of EF-HOMO and EF-LUMO distance agreed excellently with UPS and Kelvin-probe results. For (ii) we found theoretically that the pinning phenomena occur at systems even without any electronic states in the HOMO-LUMO gap, and thereby indicate that this is a universal Fermi-level pinning-like phenomena for various band gap materials, even if specific interface states do not exist upon contact. We further obtained for Gaussian-distributed HOMO and LUMO that the minimal hole and electron injection barriers are quantitatively determined by degree of standard deviations of HOMO and LUMO bands, which are in excellent agreement with the experimental results. Furthermore, our results provide a guideline for approaching the “zero” injection barriers.
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- 2017
15. Dynamic processes of charges generation in intermediate connectors for tandem organic light emitting diodes
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Wen-Qin Wang, Jian-Xin Tang, Liwen Cheng, Xianghua Zeng, Lin-Tai Shang, Xiaoshuang Shen, Yan-Qing Li, and Jinpeng Yang
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Materials science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Capacitance ,Molybdenum trioxide ,Biomaterials ,chemistry.chemical_compound ,Transition metal ,Materials Chemistry ,OLED ,Electrical and Electronic Engineering ,Deposition (law) ,Tandem ,business.industry ,Doping ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Optoelectronics ,0210 nano-technology ,business ,Current density - Abstract
The role of transition metal oxides (TMOs) based intermediate connectors in tandem organic light emitting diodes (OLEDs) has been studied via capacitance-voltage and current-voltage characteristics, in order to elucidate the dynamic processes of charges generation and transport within externally applied voltages. The TMO-based intermediate connectors are composed of molybdenum trioxide (MoO3) and cesium azide (CsN3)-doped-4, 7–diphenyl-1, 10-phenanthroline (BPhen) layers, where MoO3 and CsN3 are used due to low deposition temperatures. From the obtained results of capacitance and current density, charges generation in CsN3:BPhen/MoO3/NPB is proposed to the defect states in thermally evaporated MoO3, which offers a minimal energy offset for charges generation. Moreover, our results clearly indicate that charges generation efficiency is not only relying on the MoO3-NPB interface, but also influenced by CsN3:BPhen-MoO3 interface. CsN3 doped BPhen layer further improves charges separation efficiency, which finally results in favorable charges transport into the adjacent layers and ensure to function efficiently for tandem OLEDs.
- Published
- 2017
16. A low-cost and low-temperature processable zinc oxide-polyethylenimine (ZnO:PEI) nano-composite as cathode buffer layer for organic and perovskite solar cells
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Qun Luo, Lianping Zhang, Na Wu, Yongzhen Yang, Zhongmin Bao, Junfeng Wei, Xuguang Liu, Xiaorui Jia, Chang-Qi Ma, and Yan-Qing Li
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Polyethylenimine ,Nanocomposite ,Materials science ,Organic solar cell ,Open-circuit voltage ,Oxide ,Perovskite solar cell ,Heterojunction ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Materials Chemistry ,Electrical and Electronic Engineering ,0210 nano-technology ,Perovskite (structure) - Abstract
Nanocomposite buffer layer based on metal oxide and polymer is merging as a novel buffer layer for organic solar cells, which combines the high charge carrier mobility of metal oxide and good film formation properties of polymer. In this work, a nanocomposite of zinc oxide and a commercialized available polyethylenimine (PEI) was developed and used as the cathode buffer layer (CBL) for the inverted organic solar cells and p-i-n heterojunction perovskite solar cells. The cooperation of PEI in nano ZnO offers a good film forming ability of the composite material, which is an advantage in device fabrication. In addition, power conversion efficiency (PCE) of the ZnO:PEI CBL based device was also improved when compared to that of ZnO-only and PEI-only devices. The highest PCE of P3HT:PC 61 BM and PTB7-Th:PC 61 BM devices reached to 3.57% and 8.16%, respectively. More importantly, there is no obvious device performance loss with the increase of the layer thickness of ZnO:PEI CBL to 60 nm in organic solar cells, which is in contrast to the PEI based devices, whose device performance decreases dramatically when the PEI layer thickness is higher than 6 nm. Such a nano composite material is also applicable in inverted heterojunction perovskite solar cells. A PCE of 11.76% was achieved for the perovskite solar cell with a thick ZnO:PEI CBL (150 nm) CBL, which is around 1.71% higher than that of the reference cell without CBL, or with ZnO CBL. In addition, stability of the organic and perovskite solar cells having ZnO:PEI CBL was also found to be improved in comparison with that of PEI based device.
- Published
- 2016
17. Spectrally stable blue electroluminescence of mixed-halide perovskite light-emitting diodes featuring ion migration inhibition
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Jianming Yang, Hai-Yan Wu, Yu-Han Wang, Yan-Qing Li, Yu Tian, Yu-Xin Luo, Jian-Xin Tang, and Li-Peng Cheng
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Brightness ,Materials science ,Halide ,02 engineering and technology ,Electroluminescence ,010402 general chemistry ,01 natural sciences ,Ion ,law.invention ,Biomaterials ,Metal ,law ,Phase (matter) ,Materials Chemistry ,Electrical and Electronic Engineering ,Perovskite (structure) ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,0210 nano-technology ,business ,Light-emitting diode - Abstract
Perovskites light emitting diodes (PeLEDs) are promising candidates for next-generation display devices because of their attractive properties of low-cost, solution processability and excellent color purity. For metal halide perovskite materials, the emission tuning can be easily achieved by altering halide composition. However, blue PeLEDs with chlorine incorporation usually suffer from the severe phase segregation and ion migration, resulting in the red-shifted electroluminescence and the efficiency degradation. Here, the partial substitution of Pb2+ ions with non-toxic Sr2+ is adopted to enhance the formation energy of Sr-alloyed perovskite films, leading to the negligible electroluminescence in electrically driven blue PeLEDs. The maximum brightness and efficiency are optimized simultaneously. Further, such a substitution can greatly enhance the thermal and operational stabilities of PeLEDs.
- Published
- 2020
18. Photo-induced storage and mask-free arbitrary micro-patterning in solution-processable and simple-structured photochromic organic light-emitting diodes
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Wei Huang, Wenwen Li, Xinwen Zhang, Qi Wei, Wei Hu, Bingyan Wei, Yan-qing Lu, Yan Qian, Xiuxia Xu, Linghai Xie, Jianyun Wang, and Xiaohong Yan
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Materials science ,business.industry ,Doping ,General Chemistry ,Optical storage ,Condensed Matter Physics ,Photochemistry ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Photochromism ,chemistry.chemical_compound ,Diarylethene ,chemistry ,Materials Chemistry ,OLED ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Luminescence ,Current density ,Visible spectrum - Abstract
A photochromic diarylethene-based compound BMTA, which undergoes a reversible conversion between ring- open and closed isomers by alternating UV and visible light illumination, has been designed and synthesized. By utilizing a mask-free Digital Micro-mirror Device (DMD) micro-lithography system, arbitrary micro-photopatterning in polymer films doped with BMTA can be easily obtained with UV light writing. This recorded photo information can easily be erased by further visible light irradiation. The reversible and rewritable optical storage is based on photo-switched intermolecular energy transfer between the emissive host and the ring-closed isomer c -BMTA. Furthermore, the solution-processable organic light-emitting devices (OLEDs) with the single emitting layer doped with BMTA were fabricated, which exhibit rewritable memory behavior with light control. The luminescence and current density decrease significantly upon UV light irradiation, and recover by further visible light illumination. This is because the hole trapping is much facilitated in closed-ring isomer based devices, due to elevated HOMO level of c -BMTA. Without incorporating any cross-linking layer, the maximum luminescence and current density on/off ratios of this solution-processable and simple-structured device are 1.9 × 10 3 and 1.4 × 10 2 , respectively. Arbitrary micro-photolithography of OLEDs by DMD system has also been demonstrated, which shows great prospects in large-scale production of high resolution OLED displays.
- Published
- 2015
19. The role of gap states on energy level alignment at an α-NPD/HAT(CN) 6 charge generation interface
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Nobuo Ueno, Satoshi Kera, Fabio Bussolotti, Yan-Qing Li, Jinpeng Yang, Xianghua Zeng, and Jian-Xin Tang
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Photoemission spectroscopy ,Chemistry ,General Chemistry ,Condensed Matter Physics ,medicine.disease_cause ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Charge generation ,Electron injection ,Fermi level pinning ,Materials Chemistry ,medicine ,Electrical and Electronic Engineering ,Atomic physics ,HOMO/LUMO ,Ultraviolet ,Ultraviolet photoelectron spectroscopy - Abstract
We report the effect of gap states on energy level alignment in a typical organic charge generation interface of N,N-bis(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (α-NPD)/hexaazatriphenylene−hexacarbonitrile [HAT(CN) 6 ] by using ultraviolet and X-ray photoemission spectroscopy. The gap states tailed from the highest occupied molecular orbital (HOMO) onset of α-NPD dominate the Fermi level pinning at the α-NPD( 6 interface, which is favorable for charges generation upon bias operation and facilitates the electron injection from the HOMO-tail region of α-NPD to the lowest unoccupied molecular orbital (LUMO) region of HAT(CN) 6 .
- Published
- 2015
20. Efficient solution-processed red organic light-emitting diode based on an electron-donating building block of pyrrolo[3,2-b]pyrrole
- Author
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Zhou, Yu, primary, Zhang, Ming, additional, Ye, Jun, additional, Liu, Huan, additional, Wang, Kai, additional, Yuan, Yi, additional, Du, Yan-Qing, additional, Zhang, Chi, additional, Zheng, Cai-Jun, additional, and Zhang, Xiao-Hong, additional
- Published
- 2019
- Full Text
- View/download PDF
21. Theoretical perspective to light outcoupling and management in perovskite light-emitting diodes
- Author
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Meng, Shuai-Shuai, primary, Li, Yan-Qing, additional, and Tang, Jian-Xin, additional
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- 2018
- Full Text
- View/download PDF
22. Annealing-induced phase separation in small-molecular bulk heterojunctions
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Chun-Sing Lee, Huai-Xin Wei, Yan-Qing Li, Jian-Xin Tang, and Xiangyu Chen
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Molecular diffusion ,Materials science ,Annealing (metallurgy) ,Intermolecular force ,Analytical chemistry ,Heterojunction ,General Chemistry ,Condensed Matter Physics ,Polymer solar cell ,Surface energy ,Microscopic scale ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Chemical physics ,Phase (matter) ,Materials Chemistry ,Electrical and Electronic Engineering - Abstract
Morphology optimization of donor–acceptor bulk heterojunctions at microscopic scale is critical for improving performance of organic photovoltaic devices. Here, effects of thermal annealing on phase separation processes in small-molecular bulk heterojunctions with different geometrical structures (i.e., PTCDA, TiOPc, CuPc and C60) are investigated with ultraviolet and X-ray photoemission spectroscopies. It was identified that post-annealing treatment caused the different degrees of vertical diffusions at the bulk heterojunctions, leading to non-uniform composition distributions. Variations in phase separations are mainly due to the differences in surface energy of the involved materials, which play a crucial role in the intermolecular interactions and the molecular diffusion. Low-surface-energy materials were found to segregate preferentially on the surface for minimizing total energy of the systems.
- Published
- 2014
23. Interface optimization using diindenoperylene for C 60 thin film transistors with high electron mobility and stability
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Jinpeng Yang, Nobuo Ueno, Fabio Bussolotti, Qijun Sun, Keiichirou Yonezawa, Jian-Xin Tang, Satoshi Kera, Alexander Gerlach, Xu Gao, Frank Schreiber, Alexander Hinderhofer, Yan-Qing Li, Sui-Dong Wang, and Katharina Broch
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Electron mobility ,Materials science ,business.industry ,Interface (computing) ,Transistor ,Gate insulator ,General Chemistry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,chemistry.chemical_compound ,chemistry ,law ,Diindenoperylene ,Thin-film transistor ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,High electron ,business ,Layer (electronics) - Abstract
C60-based organic thin film transistors (OTFTs) with high electron mobility and high oper- ational stability are achieved with (1 1 1) oriented C60 films grown by using template effects of diindenoperylene (DIP) under layer on the SiO2 gate insulator. The electron mobility of the C60 transistor is significantly increased from 0.21 cm 2
- Published
- 2014
24. Fermi-level pinning appears upon weak electrode-organic contact without gap states: A universal phenomenon
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Yang, Jin-Peng, primary, Shang, Lin-Tai, additional, Bussolotti, Fabio, additional, Cheng, Li-Wen, additional, Wang, Wen-Qing, additional, Zeng, Xiang-Hua, additional, Kera, Satoshi, additional, Li, Yan-Qing, additional, Tang, Jian-Xin, additional, and Ueno, Nobuo, additional
- Published
- 2017
- Full Text
- View/download PDF
25. Dynamic processes of charges generation in intermediate connectors for tandem organic light emitting diodes
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Yang, Jin-Peng, primary, Wang, Wen-Qin, additional, Shang, Lin-Tai, additional, Cheng, Li-Wen, additional, Shen, Xiao-Shuang, additional, Zeng, Xiang-Hua, additional, Li, Yan-Qing, additional, and Tang, Jian-Xin, additional
- Published
- 2017
- Full Text
- View/download PDF
26. A low-cost and low-temperature processable zinc oxide-polyethylenimine (ZnO:PEI) nano-composite as cathode buffer layer for organic and perovskite solar cells
- Author
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Jia, Xiaorui, primary, Wu, Na, additional, Wei, Junfeng, additional, Zhang, Lianping, additional, Luo, Qun, additional, Bao, Zhongmin, additional, Li, Yan-Qing, additional, Yang, Yongzhen, additional, Liu, Xuguang, additional, and Ma, Chang-Qi, additional
- Published
- 2016
- Full Text
- View/download PDF
27. The role of gap states on energy level alignment at an α-NPD/HAT(CN) 6 charge generation interface
- Author
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Yang, Jin-Peng, primary, Bussolotti, Fabio, additional, Li, Yan-Qing, additional, Zeng, Xiang-Hua, additional, Kera, Satoshi, additional, Tang, Jian-Xin, additional, and Ueno, Nobuo, additional
- Published
- 2015
- Full Text
- View/download PDF
28. Unraveling the light-induced degradation mechanism of CH3NH3PbI3 perovskite films.
- Author
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Hong, Qiu-Ming, Xu, Rui-Peng, Jin, Teng-Yu, Tang, Jian-Xin, and Li, Yan-Qing
- Subjects
- *
LEAD halides , *PEROVSKITE , *SOLAR cells , *RENEWABLE energy sources , *BINDING energy - Abstract
Abstract While metal halide hybrid perovskite solar cells (PeSCs) are remarkably efficient, the rapid and undesirable degradation limit their practical applications for renewable energy sources. Herein, the evolution of perovskite decomposition under white light illumination has been investigated under the ultrahigh vacuum conditions, which can effectively rule out the influence of other factors such as oxygen or moisture. The chemical composition, electronic structure, surface morphology, and crystal structure of CH 3 NH 3 PbI 3 perovskite films have been systematically characterized by X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS), scanning electron microscopy, and X-ray diffraction techniques. The surface roughening with cracks and defects occurs in CH 3 NH 3 PbI 3 perovskite films after a short-time white-light illumination in ultrahigh vacuum. In situ compositional analysis reveals the decomposition of the perovskite films with the appearance of metallic Pb feature, which is accompanied with the energy level shift towards higher binding energy during the illumination process. However, the decomposition rate is decreased and becomes saturated after exposed to light illumination for 24 h. These findings provide a direct evidence that CH 3 NH 3 PbI 3 perovskite is photosensitive, and a light-induced degradation mechanism is proposed. Graphical abstract Image 1 Highlights • The perovskite decomposition under white light illumination is explored under ultrahigh vacuum conditions. • In-situ compositional analysis reveals the perovskite decomposition with the appearance of metallic Pb. • A light-induced degradation mechanism is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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