Crystallography,Packing Mode,and Aggregation State of Chlorinated Isomers for Efficient Organic Solar Cells  

作　　者：Hanjian Lai Xue Lai Zi-Yi Chen Yulin Zhu Hengtao Wang Hui Chen Pu Tan Yiwu Zhu Yuanzhu Zhang Feng He 

机构地区：[1]Department of Chemistry,Shenzhen Grubbs Institute,Southern University of Science and Technology,Shenzhen 518055 [2]School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150001 [3]Guangdong Provincial Key Laboratory of Catalysis,Southern University of Science and Technology,Shenzhen 518055

出　　处：《CCS Chemistry》2023年第5期1118-1129,共12页中国化学会会刊（英文）

基　　金：supported by the National Natural Science Foundation of China(grant nos.21733005,21975115);Guangdong Provincial Key Laboratory of Catalysis(grant no.2020B121201002);Guangdong Innovative and Entrepreneurial Research Team Program(grant no.2016ZT06G587);Shenzhen Fundamental Research Program(grant nos.JCYJ20210324120010028,JCYJ20200109140801751);Shenzhen Sci-Tech Fund(grant no.KYTDPT20181011104007).

摘　　要：Revealing the molecular packing,intermolecular interactions,and aggregation behaviors in the nanocrystalline bulk heterojunction(BHJ)domains undertake the tasks for future materials design for efficient solar cells,especially in understanding the structure–property relationship of isomeric non-fullerene acceptors(NFAs).Theoretical calculations reveal that 2ClIC-βδ,withβ-andδ-chlorine-substituted terminal groups,achieves a relatively higher dipole moment for enhanced intermolecular interactions.More importantly,when comparing the single-crystal X-ray diffraction patterns of three isomeric NFAs,BTIC-BO4Cl-βδ,BTIC-BO4Cl-βγ,and BTIC-BO4Cl,the synergistic effect of chlorine atoms at theβ-andδ-positions endows BTIC-BO4Cl-βδbetter molecular planarity with a dihedral angle of 1.14°.In turn,this creates the shortestπ∙∙∙πdistance(3.28Å)and smallest binding energies(−51.66 kcal mol^(−1))of the three NFAs,resulting in the tightest three-dimensional network packing structure with a framework of L_(x)=14.0Åand L_(y)=13.6Å.Such a structure has multiple intermolecular interactions for better charge transfer.However,the chlorine atomat theγ-position in the other two isomers contributes to non-intermolecular interactions with subordinate packing arrangements.Subsequently,the red-shifted UV-absorption and higher electron mobility observed in neat films of BTIC-BO4Cl-βδagree well with its more ordered crystallinity.This leads to a more suitable fiber-like phase separation in the corresponding active blend,ultimately improving the device performance with superior charge transport.As a result,the highest power conversion efficiency of 17.04%with a current density of 26.07 mA cm^(−2)was obtained with the BTIC-BO4Cl-βδ-based device.The carrier dynamics test and grazing incidence wide-angle X-ray scattering measurement indicate that the packing arrangement of molecules in the nanocrystalline BHJ domains is consistent with their crystallinity.This work investigates the structure–property differences

关 键 词：chlorinated isomer three-dimensional network packing size of framework intermolecular junction single crystal 

分 类 号：O57[理学—粒子物理与原子核物理]