Morphology and efficiency enhancements of PTB7-Th:ITIC nonfullerene organic solar cells processed via solvent vapor annealing

作     者：Robert S. Gurney Wei Li Yu Yan Dan Liu Andrew J. Pearson Tao Wang Robert S.Gurney;Wei Li;Yu Yan;Dan Liu;Andrew J.Pearson;Tao Wang

作者机构：School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070HubeiChina State Key Laboratory of Silicate Materials for ArchitecturesWuhan University of TechnologyWuhan 430070HubeiChina Cavendish LaboratoryUniversity of CambridgeJ. J. Thomson AvenueCambridge CB3 0HEUK 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2019年第28卷第10期

页      面：148-156页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：supported by the Natural Science Foundation of Hubei Province (Grant no. 2018CFA055) the National Natural Science Foundation of China (Grants no. 21774097) 

主　　题：Polymer solar cells Non-fullerene Solvent vapor annealing 

摘      要：The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain size in improving performance, which can be tuned by subjecting the photovoltaic materials to solvent vapor annealing (SVA). In our PTB7-Th:ITIC devices, the PCE can be improved by exposing the device to solvent vapor for 60 s after solution casting. The solvent vapor prolongs reorganizational time and increases molecular ordering and domain size/phase separation, which are sub-optimal in pristine PTB7-Th:ITIC blend films. This improved morphology results in better charge mobility, reduced recombination, and ultimately an improved PCE from 7.1% to 7.9% when using CS2 as the annealing solvent. This simple SVA technique can be applied to a range of OPV systems where the molecular ordering is inferior within the as-cast photoactive layer.