Charge Photogeneration and Recombination in Fluorine-Substituted Polymer Solar Cells

Frontiers in Chemistry

Wei Zhang¹  Ming-Ming Huo²  Rong Hu⁴  Yurong Liu⁴  Mengyao Qing⁵  Jun Peng⁵  Jianjun Jiang⁵  Xiaochuan He⁶ 

[1] Guangzhou University-Linköping University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou, China;Qingdao Branch, Naval Aeronautical University, Qingdao, China;Research Center for Advanced Information Materials (CAIM), Huangpu Research and Graduate School of Guangzhou University, Guangzhou, China;School of Materials Science and Engineering, Chongqing University of Arts and Sciences, Chongqing, China;School of Physics and Materials Science, Guangzhou University, Guangzhou, China;Songshan Lake Materials Laboratory, Dongguan, China;

关键词: polymer solar cells;    fluorine substitution;    charge transport;    charge recombination;    power conversion efficiency;   

DOI  :  10.3389/fchem.2022.846898

来源: DOAJ

【 摘 要 】

In this contribution, we studied the effect of fluorine substitution on photogenerated charge generation, transport, and recombination in polymer solar cells. Two conjugated polymer materials, PBDTTT-E (fluorine free) and PTB7 (one fluorine substitution), were compared thoroughly. Meanwhile, various characterization techniques, including atomic force microscopy, steady-state spectroscopy, transient absorption spectroscopy, spectroelectrochemistry, and electrical measurements, were employed to analyse the correlation between molecular structure and device performance. The results showed that the influence of fluorine substitution on both the exciton binding energy of the polymer and the carrier recombination dynamics in the ultrafast timescale on the polymer was weak. However, we found that the fluorine substitution could enhance the exciton lifetime in neat polymer film, and it also could increase the mobility of photogenerated charge. Moreover, it was found that the SOMO energy level distribution of the donor in a PTB7:PC71BM solar cell could facilitate hole transport from the donor/acceptor interface to the inner of the donor phase, showing a better advantage than the PBDTTT-E:PC71BM solar cell. Therefore, fluorine substitution played a critical role for high-efficiency polymer solar cells.

【 授权许可】

Unknown