Nonconjugated Terpolymer Acceptors with Two Different Fused-Ring Electron-Deficient Building Blocks for Efficient All-Polymer Solar Cells

Wenyan Su; Qunping Fan; Ishita Jalan; Yufei Wang; Wenhong Peng; Tao Guo; Weiguo Zhu; Donghong Yu; Lintao Hou; Ellen Moons; Ergang Wang

doi:10.1021/acsami.0c17722

Nonconjugated Terpolymer Acceptors with Two Different Fused-Ring Electron-Deficient Building Blocks for Efficient All-Polymer Solar Cells

ACS Appl Mater Interfaces. 2021 Feb 10;13(5):6442-6449. doi: 10.1021/acsami.0c17722. Epub 2021 Jan 26.

Authors

Wenyan Su^{1

2

3}, Qunping Fan², Ishita Jalan⁴, Yufei Wang¹, Wenhong Peng^{2

5}, Tao Guo^{2

6}, Weiguo Zhu⁵, Donghong Yu^{7

8}, Lintao Hou¹, Ellen Moons³, Ergang Wang^{2

9}

Affiliations

¹ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, 510632 Guangzhou, China.
² Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
³ Department of Engineering and Physics, Karlstad University, SE-651 88 Karlstad, Sweden.
⁴ Department of Engineering and Chemical Sciences, Karlstad University, SE-651 88 Karlstad, Sweden.
⁵ School of Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, 213164 Changzhou, China.
⁶ School of Chemistry and Chemical Engineering, Henan University of Technology, 450001 Zhengzhou, China.
⁷ Department of Chemistry and Bioscience, Aalborg University, DK-9220 Aalborg, Denmark.
⁸ Sino-Danish Center for Education and Research, DK-8000 Aarhus, Denmark.
⁹ School of Materials Science and Engineering, Zhengzhou University, 450001 Zhengzhou, China.

Abstract

The ternary polymerization strategy of incorporating different donor and acceptor units forming terpolymers as photovoltaic materials has been proven advantageous in improving power conversion efficiencies (PCEs) of polymer solar cells (PSCs). Herein, a series of low band gap nonconjugated terpolymer acceptors based on two different fused-ring electron-deficient building blocks (IDIC16 and ITIC) with adjustable photoelectric properties were developed. As the third component, ITIC building blocks with a larger π-conjugation structure, shorter solubilizing side chains, and red-shifted absorption spectrum were incorporated into an IDIC16-based nonconjugated copolymer acceptor PF1-TS4, which built up the terpolymers with two conjugated building blocks linked by flexible thioalkyl chain-thiophene segments. With the increasing ITIC content, terpolymers show gradually broadened absorption spectra and slightly down-shifted lowest unoccupied molecular orbital levels. The active layer based on terpolymer PF1-TS4-60 with a 60% ITIC unit presents more balanced hole and electron mobilities, higher photoluminescence quenching efficiency, and improved morphology compared to those based on PF1-TS4. In all-polymer solar cells (all-PSCs), PF1-TS4-60, matched with a wide band gap polymer donor PM6, achieved a similar open-circuit voltage (V_oc) of 0.99 V, a dramatically increased short-circuit current density (J_sc) of 15.30 mA cm^-2, and fill factor (FF) of 61.4% compared to PF1-TS4 (V_oc = 0.99 V, J_sc = 11.21 mA cm^-2, and FF = 55.6%). As a result, the PF1-TS4-60-based all-PSCs achieved a PCE of 9.31%, which is ∼50% higher than the PF1-TS4-based ones (6.17%). The results demonstrate a promising approach to develop high-performance nonconjugated terpolymer acceptors for efficient all-PSCs by means of ternary polymerization using two different A-D-A-structured fused-ring electron-deficient building blocks.

Keywords: all-polymer solar cells; copolymer; nonconjugated polymer acceptor; power conversion efficiency; terpolymer.