Enhance the efficiency of polymer solar cells through regulating phase segregation and improving charge transport via non-toxic halogen-free additive. (April 2021)

• Record Type: Journal Article
• Authors: Fu, Zhijie; Liu, Xingpeng; Wang, Yufei; Du, Sanshan; Tong, Junfeng; Li, Jianfeng; Zhang, Rongling; Yang, Chunming; Xia, Yangjun
• Is Part Of: Solar energy. Volume 218(2021)
• Page Start: 375
• Page End: 382
• Publication Date: 2021-04
• Subjects: Polymer solar cells -- Additive -- Dibenzyl ether -- Halogen-free; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2021.03.012
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A halogen-free additive, dibenzyl ether, was successfully introduced into PSCs. The dibenzyl ether additive could boost the phase composition distribution. The morphology, exciton dissociation, charge transport ability can be improved. Abstract: Conventional additives like 1, 8-diiodooctane (DIO) and 1-chloronaphthalene (CN) play an essential role in optimization of blend film morphology of polymer solar cells (PSCs). However, they have halogenated elements in their end groups, which are harmful to the environment and humans, limiting large-scale applications. In this work, a novel non-toxic and non-halogen additive, dibenzyl ether (DE), was introduced into PTB7-Th:PC71 BM based PSCs, and the role of the DE additive was systemically investigated. The results showed that DE additive can not only adjust phase separation and optimize the morphology of blend film, but also promote the mobility of hole and electron. The grazing-incidence small-angle X-ray scattering (GISAXS) showed that the introduction of DE increased the interface area between PTB7-Th and PC71 BM, which can promote exciton dissociation, and achieve better charge transport. Transient photovoltage (TPV) and transient photocurrent (TPC) measurements show that carrier recombination of the additive-containing devices can be effectively inhibited with improved charge transport efficiency of the active layer. Consequently, the devices with DE additive achieve power conversion efficiency (PCE) of 9.53% and a fill factor (FF) of 70.41%. Our non-toxic and non-halogen additive provides a potential solution for the preparation of environmental-friendly PSCs in the future.