Статья

Highly Efficient Fullerene-Free Organic Solar Cells Operate at Near Zero Highest Occupied Molecular Orbital Offsets

Shuixing LiMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. ChinaLingling ZhanMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. ChinaChenkai SunInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. ChinaHaiming ZhuDepartment of Chemistry, Zhejiang University, Hangzhou 310027, P.R. ChinaGuanqing ZhouDepartment of Physics and Astronomy and Collaborative Innovation Center of IFSA (CICFSA), Shanghai Jiao Tong University, Shanghai 200240, P.R. ChinaWeitao YangMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. ChinaMinmin ShiMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. ChinaChang‐Zhi LiMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. ChinaJianhui HouInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. ChinaYongfang LiInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. ChinaHongzheng ChenMOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P.R. China

2019en

ABI

Аннотация

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.

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Идентификаторы

DOI: 10.1021/jacs.8b12126

Цитирования и источники

Цитирований: 2Использованных источников: 0

Показатели — AkademScholar