Adjusting the photovoltaic performance of big fused ring-based small molecules by tailoring with different modifications

Min Li; Manjun Xiao; Zuojia Li

doi:10.1039/d1ra08239f

Adjusting the photovoltaic performance of big fused ring-based small molecules by tailoring with different modifications

RSC Adv. 2021 Dec 13;11(63):39625-39635. doi: 10.1039/d1ra08239f.

Authors

Min Li^{1

2}, Manjun Xiao³, Zuojia Li¹

Affiliations

¹ Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices, School of Chemistry, Biology and Materials Science, East China University of Technology Nanchang 330013 P. R. China lzjshihaoren@126.com.
² School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University Changzhou 213164 China limin20a@126.com.
³ College of Chemistry, Key Lab of Environment-Friendly Chemistry and Application in the Ministry of Education, Xiangtan University Xiangtan 411105 China xmj0704@163.com.

Abstract

Three novel A-D-A type small-molecule donor materials, namely AAN-DPP₂, AAN(T-DPP)₂ and AANT(T-DPP)₂, with anthanthrene (AAN) as the electron-donating core, diketopyrrolopyrrole (DPP) as the electron-accepting moiety, and thiophene as π-bridge units, have been designed and synthesized for application in bulk-heterojunction (BHJ) organic solar cells (OSCs). Compared to AAN-DPP₂, devices based on AAN(T-DPP)₂ and AANT(T-DPP)₂ show better photovoltaic performance due to broader absorption and better planarity of the molecular backbone. A maximum power conversion efficiency (PCE) of 2.33% with a short-circuit current density (J _sc) of 6.82 mA cm^-2 and a fill factor (FF) of 39.80 was obtained in the AAN(T-DPP)₂/PC₇₁BM-based solar cells. This is resulting from the suitable thickness of the active layer, improving the ability of catching light and decreasing the twist angle of the backbone by inserting a thiophene spacer. The results indicate that strategic substitution of π-bridges and side-chains in A-D-A type SMs is an efficient strategy to improve photovoltaic performance.