Calculation aided miscibility manipulation enables highly efficient polythiophene:nonfullerene photovoltaic cells  

作　　者：Qi Wang Miaomiao Li Zhongxiang Peng Nigel Kirby Yunfeng Deng Long Ye Yanhou Geng 

机构地区：[1]Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Fuzhou 350207,China [2]School of Materials Science and Engineering,Tianjin University,Tianjin 300072,China [3]Tianjin Key Laboratory of Molecular Optoelectronic Science,Tianjin University,Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),Tianjin 300072,China [4]Australian Synchrotron,Clayton,Victoria 3168,Australia [5]State Key Laboratory of Luminescent Materials and Devices,South China University of Technology,Guangzhou 510640,China

出　　处：《Science China Chemistry》2021年第3期478-487,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(52073207,22075200,51703158,51933008);supported by the Peiyang Scholar Program of Tianjin University;the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology,2020skllmd-11);Peiyang Young Junior Faculty Program of Tianjin University(2019XRG-0021);Independent Innovation Fund of Tianjin University(2020XZC-0105)。

摘　　要：Polythiophenes,with merits of low cost and high scalability of synthesis,have received growing interest in organic solar cells.To date,the best-performing polythiophene:nonfullerene solar cells exhibit typical power conversion efficiencies (PCEs) of 10%–12%,which is much lower than those employing PM6-and D18-type polymers.This inferior performance is mostly limited by the improper miscibility between polythiophene and acceptors.Efforts on engineering the molecular structure to systematically tune the miscibility are required.With the aid of group contribution calculations,the miscibility of polythiophene:nonfullerene blend system was finely tuned by varying the ratios of siloxane-terminated chains and alkyl chains in ester-substituted polythiophenes through random copolymerization.Based on a series of the polythiophene and nonfullerene acceptors,the detailed analysis of blend miscibility and performance reveals a surprising anticorrelation between the Flory-Huggins interaction parameter (χ_(aa)) and the optimal time of solvent vapor annealing for device performance across these systems.Primarily due to the slightly higher χ_(aa),the blend of PDCBT-Cl-Si5 and ITIC-Th1 results in a record-high PCE of 12.85%in polythiophene:nonfullerene solar cells.The results not only provide a calculation-guided approach for molecular design but also prove that precise control of the miscibility is an effective way to design high-performance polythiophene:nonfullerene blends and beyond.

关 键 词：nonfullerene organic solar cells POLYTHIOPHENES MISCIBILITY molecular design 

分 类 号：TM914.4[电气工程—电力电子与电力传动] TQ317[化学工程—高聚物工业]