Enhanced photovoltaic effect from naphtho[2, 3-c]thiophene-4, 9-dione-based polymers through alkyl side chain induced backbone distortion. Issue 29 (16th July 2020)

• Record Type: Journal Article
• Authors: Bi, Xiaoman; Zhang, Tao; An, Cunbin; Bi, Pengqing; Ma, Kangqiao; Li, Sunsun; Xian, Kaihu; Lv, Qianglong; Zhang, Shaoqing; Yao, Huifeng; Xu, Bowei; Zhang, Jianqi; Cao, Shaokui; Hou, Jianhui
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 29(2020)
• Page Start: 14706
• Page End: 14712
• Publication Date: 2020-07-16
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta02859b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Two conjugated polymers with different side chain substituted positions were synthesized to study their photovoltaic performances. Abstract : The innovation of photoactive layer materials is crucial for improving the power conversion efficiency (PCE) of polymer solar cells (PSCs). Herein, we report two polymer donors (PBTN- o and PBTN- p ), which only differ in alkyl chains substituted at sites (6, 7- or 5, 8-) of the naphtho[2, 3- c ]thiophene-4, 9-dione (NTD) unit. The single crystals of both NTD monomers demonstrate that NTD with alkyl chains at the 6, 7-sites has a planar NTD skeleton, and surprisingly, NTD with alkyl chains at the 5, 8-sites produces a bent NTD skeleton. The bent NTD-based polymer (PBTN- p ) exhibits a more twisted conjugated backbone than PBTN- o . Our comparative studies show that PBTN- p possesses suitable aggregation properties that can optimize the photoactive layer morphology in NF PSCs. In PSCs, the optimal PBTN- o :BO-4Cl-based device shows a PCE of 11.85% with a V OC of 0.84 V, J SC of 22.41 mA cm −2, and FF of 0.63. In contrast, the optimal PBTN- p :BO-4Cl-based device exhibits a better PCE of 14.10% with the same V OC of 0.84 V, and an enhanced J SC of 24.67 mA cm −2 and FF of 0.68. This work provides a new insight into BHJ morphology optimization by side chain induced polymer main chain twisting in PSCs.