Halogenation on terminal groups of ITIC based electron acceptors as an effective strategy for efficient polymer solar cells. (1st January 2020)

• Record Type: Journal Article
• Authors: Lu, Shujing; Li, Feng; Zhang, Kaili; Zhu, Jie; Cui, Wen; Yang, Renqiang; Yu, Liangmin; Sun, Mingliang
• Is Part Of: Solar energy. Volume 195(2020)
• Page Start: 429
• Page End: 435
• Publication Date: 2020-01-01
• Subjects: Halogenation -- Non-fullerene acceptors -- Power conversion efficiencies; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2019.11.074
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: Highlights: 10–12% High power conversion efficiency is achieved by halogenated ITIC and BDT polymer. Fluorinated, chlorinated and brominated ITIC acceptor all fit BDT-BDD backboned donor. 70% FF are achieved by all halogenated ITIC based devices. Abstract: Acceptor halogenation is an excellent modification method for modulating molecular energy levels, improving optical absorption, shortening the intermolecular packing distance thus ameliorating morphologies and achieving effective exciton dissociation and charge transfer of organic photovoltaic device. In this work, F, Cl and Br terminated ITIC small molecule acceptor (SMA) derivatives (IT-2F, IT-2Cl and IT-2Br) are designed and synthesized to compare the halogen substitution effect. Among these three acceptors, IT-2F based PSCs devices show the highest power conversion efficiencies (PCEs) around 12.08%, but Br terminated ITIC show downshifted LUMO energy level. Brominated ITIC show comparable PCEs with Cl and F terminated compound, and moreover chlorinated and brominated ITIC show low synthesis cost and easy purification than fluorinated materials, which may be favorable for future commercialization.