Journal ArticleDOI
Highly Efficient Fullerene-Free Organic Solar Cells Operate at Near Zero Highest Occupied Molecular Orbital Offsets.
Shuixing Li,Lingling Zhan,Chenkai Sun,Haiming Zhu,Guanqing Zhou,Weitao Yang,Minmin Shi,Chang-Zhi Li,Jianhui Hou,Yongfang Li,Hongzheng Chen +10 more
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TLDR
Investigating a series of fullerene-free organic solar cells based on six different donor:acceptor (D:A) blends with varied highest occupied molecular orbital (HOMO) offsets demonstrates not only the validity of high-performance OSCs operating at the near zero HOMO offsets but also the charge dynamic insights of these blends, which will help gain understanding on the further improvement of Oscs.Abstract:
Herein, we investigated a series of fullerene-free organic solar cells (OSCs) based on six different donor:acceptor (D:A) blends with varied highest occupied molecular orbital (HOMO) offsets from -0.05 to 0.21 eV. First, to verify the energetic compatibility of a specific D:A pair, especially for HOMO offsets, we established a simple method to estimate the hole transfer tendencies between D and A by using bilayer hole-only devices. It reveals that the asymmetrical diode effect of the bilayer hole-only devices can correlate with the FF and Jsc of the relevant OSCs. Second, to find out whether HOMO offset is the main restriction of hole transfer, we measured transient absorption spectra and examined the hole transfer behavior in the blends, revealing that the occurrence of hole transfer is independent of the HOMO offsets and ultrafast in the time scale of ≤4.6 ps for those blends with ≥0 eV HOMO offsets. In contrast, a negative HOMO offset can significantly slow down the hole transfer with a half-time of ∼400 ps. Furthermore, we compare the device parameters under varied light intensities and discover that the bimolecular recombination should be one of the main restrictions for high device performance. Surprisingly, small HOMO offsets of 0 and 0.06 eV can also enable high PCEs of 10.42% and 11.75% for blend 2 (PTQ10:HC-PCIC) and blend 3 (PBDB-TF:HC-PCIC), respectively. Overall, our work demonstrates not only the validity of high-performance OSCs operating at the near zero HOMO offsets but also the charge dynamic insights of these blends, which will help gain understanding on the further improvement of OSCs.read more
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Journal ArticleDOI
Over 17% efficiency ternary organic solar cells enabled by two non-fullerene acceptors working in an alloy-like model
Lingling Zhan,Shuixing Li,Tsz-Ki Lau,Yong Cui,Xinhui Lu,Minmin Shi,Chang-Zhi Li,Hanying Li,Jianhui Hou,Hongzheng Chen +9 more
TL;DR: In this article, an alloy-like composite is formed between Y6 and a newly designed derivative, BTP-M. Employing an electron-pushing methyl substituent as a replacement for the electron-withdrawing F atoms on Y6, the obtained Y6:BTP-m alloy can simultaneously optimize energy levels to reduce energy loss as well as the morphologies of the active layers to favor photocurrent generation, leading to an enhanced open-circuit voltage (Voc) of 0.875 V together with a larger shortcircuit current density (Jsc
Journal ArticleDOI
New Phase for Organic Solar Cell Research: Emergence of Y-Series Electron Acceptors and Their Perspectives
TL;DR: In this article, a new class of high-performance non-fullerene acceptors (NFAs) have been proposed for organic solar cells (OSCs), which have entered a new phase of research featuring high power conversion efficiencies.
Journal ArticleDOI
Layer-by-Layer Processed Ternary Organic Photovoltaics with Efficiency over 18.
Lingling Zhan,Shuixing Li,Xinxin Xia,Yaokai Li,Xinhui Lu,Lijian Zuo,Minmin Shi,Hongzheng Chen +7 more
TL;DR: In this article, a solution to resolve the above challenge via synergistically combining the layer-by-layer (LbL) procedure and the ternary strategy is proposed and demonstrated.
Journal ArticleDOI
Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells
Guichuan Zhang,Xian Kai Chen,Xian Kai Chen,Jingyang Xiao,Philip C. Y. Chow,Minrun Ren,Grit Kupgan,Grit Kupgan,Xuechen Jiao,Xuechen Jiao,Xuechen Jiao,Christopher C. S. Chan,Xiaoyan Du,Ruoxi Xia,Ziming Chen,Jun Yuan,Yunqiang Zhang,Shoufeng Zhang,Yidan Liu,Yingping Zou,He Yan,Kam Sing Wong,Veaceslav Coropceanu,Veaceslav Coropceanu,Ning Li,Ning Li,Christoph J. Brabec,Jean-Luc Brédas,Jean-Luc Brédas,Hin-Lap Yip,Yong Cao +30 more
TL;DR: The delocalization of exciton and electron wavefunction due to strong π-π packing of Y6 is the key for the high performance of this state-of-the-art OSC system.
Journal ArticleDOI
Improved Charge Transport and Reduced Nonradiative Energy Loss Enable Over 16% Efficiency in Ternary Polymer Solar Cells
TL;DR: This work suggests that utilizing the complementary advantages of fullerene and NFAs is a promising way to finely tune the detailed photovoltaic parameters and further improve the PCEs of PSCs.
References
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Journal ArticleDOI
Molecular Optimization Enables over 13% Efficiency in Organic Solar Cells
TL;DR: The PBDB-T-SF:IT-4F-based OSC device showed a record high efficiency, and an efficiency of over 12% can be obtained with a thickness of 100-200 nm, suggesting the promise of fullerene-free OSCs in practical applications.
Journal ArticleDOI
Organic and solution-processed tandem solar cells with 17.3% efficiency
Lingxian Meng,Yamin Zhang,Xiangjian Wan,Chenxi Li,Xin Zhang,Yanbo Wang,Xin Ke,Zuo Xiao,Liming Ding,Ruoxi Xia,Hin-Lap Yip,Yong Cao,Yongsheng Chen +12 more
TL;DR: In this article, a semi-empirical model analysis and using the tandem cell strategy to overcome the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption was performed.
Journal ArticleDOI
Organic solar cells based on non-fullerene acceptors.
TL;DR: Non-fullerene OSCs show great tunability in absorption spectra and electron energy levels, providing a wide range of new opportunities, and this Review highlights these opportunities made possible by NF acceptors.
Journal ArticleDOI
Efficient organic solar cells processed from hydrocarbon solvents
Jingbo Zhao,Yunke Li,Guofang Yang,Guofang Yang,Kui Jiang,Haoran Lin,Herald Ade,Wei Ma,He Henry Yan +8 more
TL;DR: In this paper, the synergistic effects of a hydrocarbon solvent, a novel additive, a suitable choice of polymer side chain, and strong temperature-dependent aggregation of the donor polymer are used to produce active layers of organic solar cells in an environmentally friendly way.