Manipulating the Intermolecular Interactions through Side Chain Engineering and Unilateral π‐Bridge Strategy for Efficient Small Molecular Photovoltaic Acceptor. (4th March 2022)

• Record Type: Journal Article
• Authors: Wang, Pengchao; Bi, Fuzhen; Li, Yonghai; Han, Chenyu; Zheng, Nan; Zhang, Shuai; Wang, Jianxiao; Wu, Yuanwei; Bao, Xichang
• Is Part Of: Advanced functional materials. Volume 32:Number 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-04
• Subjects: intermolecular interactions -- nonfullerene acceptors -- organic photovoltaics -- side chains -- unilateral π‐bridges; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202200166
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Thanks to the development of acceptor–donor–acceptor (A–D–A) type electron acceptors, organic solar cells (OSCs) have achieved marvelous progress in recent years. However, a systematic investigation about the structure–efficiency relationship is still highly desired to better understand the working mechanisms inside a bulk heterojunction (BHJ). In this study, new acceptors with the synergistic effect of side chain and unilateral π‐bridge strategy are designed, accounting for lower energy loss, expanded absorption, modulated intermolecular interactions and BHJ morphology. As a consequence, the resultant A–D–π–A acceptor ID‐C6Ph‐ST‐4F based binary solar cell receives an impressive efficiency up to 15.36%, much greater than the A–D–A analog ID‐C6Ph‐4F (10.75%), and ranks the best among all small molecular acceptors with symmetric or asymmetric π‐bridges. The results highlight the promising manipulation of phenylalkyl side chain and unilateral π‐bridge on intermolecular interactions among acceptor molecules and interactions between donor and acceptor (D/A) molecules. Superior interactions among acceptor molecules are an essential precondition to ensure preferable molecular assembly for charge transport, and meanwhile, moderately enhanced D/A interactions are also crucial for proper phase‐separation networks with efficient exciton dissociation and charge generation. Abstract : From a thermodynamic view, intermolecular interactions inside bulk‐heterojunctions control the basic exciton/charge behaviors and microstructures. Therefore, manipulating these interactions is of great importance. By the cooperation of phenylalkyl side chains and unilateral π‐bridge strategy, this work rationally manipulates the multidimensional interactions in photovoltaic cells, accounting for the most competitive efficiency among acceptors with unilateral or bilateral π‐bridges.