Fluorinated biselenophene-naphthalenediimide copolymers for efficient all-polymer solar cells

• Published in: Dyes and pigments 2020-12, Vol.183, p.108721, Article 108721
• Main Authors: Shi, Shengbin, Luo, Jiasi, Wu, Ziang, Liu, Bin, Su, Mengyao, Chen, Peng, Zhang, Xianhe, Feng, Kui, Woo, Han Young, Xiao, Guomin
• Format: Article
• Language: English
• Subjects: All-polymer solar cells; Fluorinated biselenophene; Polymer acceptor
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2020.108721

Biselenophene (BS) is generally considered as a promising building block for constructing organic semiconductors, and the 3-positions of selenophene in BS offer a great opportunity for further structural modification. Herein, a novel fluorinated biselenophene, 3,3′-difluoro-2,2′-biselenophene (BSF), was designed and synthesized successfully, and subsequently incorporated into a polymer backbone leading to the resulting polymer PNDIBSF. The polymer backbone planarity was significantly improved via the enhanced intramolecular noncovalent Se⋯F coulombic interactions. Meanwhile, the electronic structure of the polymer was effectively tuned by the high electronegativity of F atoms. All-polymer solar cells (all-PSCs) with J71 and PNDIBSF as polymer donor and acceptor achieved power conversion efficiency (PCE) of 5.20%. In comparsion, all-PSCs based on the nonfluorinated analogue polymer acceptor (PNDIBS) had low PCE of 2.74%. The results demonstrated that BSF is a promising building block for constructing polymer acceptor in all-PSCs, and the fluorination offers a sufficient strategy for further improving performance of selenophene-based polymer semiconductors. A new fluorinated biselenophene unit was synthesized to be applied to polymer semiconductors with high power conversion efficiency of 5.20% in all-polymer solar cells, and fluorination offers a sufficient strategy for further improving performance of selenophene-based polymer semiconductors. [Display omitted] •A novel fluorinated biselenophene was designed and synthesized successfully.•Polymer backbone planarity was significantly improved via the noncovalent Se⋯F coulombic interactions.•The fluorination leads to enhancements both in JSC and FF, with a PCE up to 5.20% in all-PSCs.