Effects of Flexible Conjugation-Break Spacers of Non-Conjugated Polymer Acceptors on Photovoltaic and Mechanical Properties of All-Polymer Solar Cells

Qiaonan Chen; Yung Hee Han; Leandro R Franco; Cleber F N Marchiori; Zewdneh Genene; C Moyses Araujo; Jin-Woo Lee; Tan Ngoc-Lan Phan; Jingnan Wu; Donghong Yu; Dong Jun Kim; Taek-Soo Kim; Lintao Hou; Bumjoon J Kim; Ergang Wang

doi:10.1007/s40820-022-00884-8

Effects of Flexible Conjugation-Break Spacers of Non-Conjugated Polymer Acceptors on Photovoltaic and Mechanical Properties of All-Polymer Solar Cells

Nanomicro Lett. 2022 Aug 13;14(1):164. doi: 10.1007/s40820-022-00884-8.

Authors

Qiaonan Chen^#^{1

2}, Yung Hee Han^#³, Leandro R Franco⁴, Cleber F N Marchiori⁴, Zewdneh Genene², C Moyses Araujo^{4

5}, Jin-Woo Lee³, Tan Ngoc-Lan Phan³, Jingnan Wu^{2

6}, Donghong Yu^{6

7}, Dong Jun Kim⁸, Taek-Soo Kim⁸, Lintao Hou⁹, Bumjoon J Kim¹⁰, Ergang Wang^{11

12}

Affiliations

¹ Siyuan Laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, 510632, People's Republic of China.
² Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
³ Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
⁴ Department of Engineering and Physics, Karlstad University, 65188, Karlstad, Sweden.
⁵ Materials Theory Division, Department of Physics and Astronomy, Uppsala University, 75120, Uppsala, Sweden.
⁶ Department of Chemistry and Bioscience, Aalborg University, 9220, Aalborg, Denmark.
⁷ Sino-Danish Center for Education and Research, 8000, Aarhus, Denmark.
⁸ Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
⁹ Siyuan Laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, 510632, People's Republic of China. thlt@jnu.edu.cn.
¹⁰ Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea. bumjoonkim@kaist.ac.kr.
¹¹ Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Göteborg, Sweden. ergang@chalmers.se.
¹² School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China. ergang@chalmers.se.

^# Contributed equally.

Abstract

Highlights:

A series of non-conjugated acceptor polymers with flexible conjugation-break spacers (FCBSs) of different lengths were synthesized.
The effect of FCBSs length on solubility of the acceptor polymers, and their photovoltaic and mechanical properties in all-polymer solar cells were explored.
This work provides useful guidelines for the design of semiconducting polymers by introducing FCBS with proper length, which can giantly improved properties that are not possible to be achieved by the state-of-the-art fully conjugated polymers.

Abstract: All-polymer solar cells (all-PSCs) possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing. Introducing flexible conjugation-break spacers (FCBSs) into backbones of polymer donor (P_D) or polymer acceptor (P_A) has been demonstrated as an efficient approach to enhance both the photovoltaic (PV) and mechanical properties of the all-PSCs. However, length dependency of FCBS on certain all-PSC related properties has not been systematically explored. In this regard, we report a series of new non-conjugated P_As by incorporating FCBS with various lengths (2, 4, and 8 carbon atoms in thioalkyl segments). Unlike common studies on so-called side-chain engineering, where longer side chains would lead to better solubility of those resulting polymers, in this work, we observe that the solubilities and the resulting photovoltaic/mechanical properties are optimized by a proper FCBS length (i.e., C2) in P_A named PYTS-C2. Its all-PSC achieves a high efficiency of 11.37%, and excellent mechanical robustness with a crack onset strain of 12.39%, significantly superior to those of the other P_As. These results firstly demonstrate the effects of FCBS lengths on the PV performance and mechanical properties of the all-PSCs, providing an effective strategy to fine-tune the structures of P_As for highly efficient and mechanically robust PSCs.

Supplementary Information: The online version contains supplementary material available at 10.1007/s40820-022-00884-8.

Keywords: All-polymer solar cells; Flexible conjugation-break spacers; Mechanical robustness; Polymer acceptors; Stretchability.