Unique Energy Alignments of a Ternary Material System toward High‐Performance Organic Photovoltaics

• DOI: 10.1002/adma.201801501
• Publication Date: 2018-05-21T18:47:05Z
• Authors: Pei Cheng; Jiayu Wang; Qianqian Zhang; Wenchao Huang; Jingshuai Zhu; Rui Wang; Sheng‐Yung Chang; Pengyu Sun; Lei Meng; Hongxiang Zhao; Hao‐Wen Cheng; Tianyi Huang; Yuqiang Liu; Chaochen Wang; Chenhui Zhu; Wei You; Xiaowei Zhan; Yang Yang
• Keywords: nonfullerene; organic solar cells; Materials Engineering; 540; energy level alignments; 01 natural sciences; 7. Clean energy; 620; Macromolecular and Materials Chemistry; 0104 chemical sciences; Physical sciences; Engineering; ternary blends; Affordable and Clean Energy; Chemical sciences; Chemical Sciences; Physical Sciences; fullerene-free; Nanoscience & Nanotechnology

AbstractIncorporating narrow‐bandgap near‐infrared absorbers as the third component in a donor/acceptor binary blend is a new strategy to improve the power conversion efficiency (PCE) of organic photovoltaics (OPV). However, there are two main restrictions: potential charge recombination in the narrow‐gap material and miscompatibility between each component. The optimized design is to employ a third component (structurally similar to the donor or acceptor) with a lowest unoccupied molecular orbital (LUMO) energy level similar to the acceptor and a highest occupied molecular orbital (HOMO) energy level similar to the donor. In this design, enhanced absorption of the active layer and enhanced charge transfer can be realized without breaking the optimized morphology of the active layer. Herein, in order to realize this design, two new narrow‐bandgap nonfullerene acceptors with suitable energy levels and chemical structures are designed, synthesized, and employed as the third component in the donor/acceptor binary blend, which boosts the PCE of OPV to 11.6%.