Affiliation:
1. State Key Laboratory and Institute of Elemento‐Organic Chemistry The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials Renewable Energy Conversion and Storage Center (RECAST) College of Chemistry Nankai University Tianjin 300071 China
2. School of Materials Science and Engineering National Institute for Advanced Materials Nankai University Tianjin 300350 China
3. State Key Laboratory of Separation Membranes and Membrane Processes and Key Laboratory of Hollow Fiber Membrane Materials and Membrane Processes (MOE) School of Chemistry Tiangong University Tianjin 300387 China
Abstract
AbstractDimeric acceptors are expected to satisfy both excellent power conversion efficiency (PCE) and operational stability of organic solar cells (OSCs). However, comparing to highly planar and symmetrical monomer‐like acceptors, the quite different steric/spatial configurations of dimeric acceptors affect device outcomes greatly. Herein, on basis of the same dimeric molecular platform that constructed by bridging central units of two monomer‐like acceptor, diverse substituents (─OCH3 for D1, ─CH3 for D2, and ─CF3 for D3) are grafted on central units to regulate the three dimensions (3D) geometries of dimeric acceptors delicately. A systematic investigation reveals the substituent‐dependent variation of energy level, absorption, and molecular packing behavior. Consequently, D2 acceptor, characteristic of more favorable configuration, affords a superior film morphology and charge transfer/transport dynamics in resulting OSCs, thus yielding an excellent PCE of 17.50% along with a good long‐term stability. This work manifests the crucially important role of central substituents in constructing high‐performance dimeric acceptors.
Funder
National Natural Science Foundation of China
Ministry of Science and Technology of the People's Republic of China