Molecular stacking controlling coherent and incoherent singlet fission in polymorph rubrene single crystals Special Issue:Emerging Investigators  

作　　者：Yanping Liu Xuexiao Yang Lei Ye Haibo Ma Haiming Zhu 

机构地区：[1]State Key Laboratory of Modern Optical Instrumentation,Key Laboratory of Excited-State Materials of Zhejiang Province,Department of Chemistry,Zhejiang University,Hangzhou,China [2]School of Chemistry and Chemical Engineering,Nanjing University,Nanjing,China [3]ZJU-Hangzhou Global Scientific and Technological Innovation Center,Hangzhou,China

出　　处：《Aggregate》2023年第5期137-144,共8页聚集体（英文）

基　　金：National Natural Science Foundation of China,Grant/Award Numbers:22273084,22073045。

摘　　要：Singlet fission(SF)is an appealing process where one photoexcited singlet transforms to two triplets,which can overcome thermalization energy loss and improve solar cell efficiency.However,it remains unclear how intermolecular coupling,which is subject to molecular stacking,controls SF pathways and dynamics.Here,we prepared polymorph rubrene single crystals with different stacking geometries,including orthorhombic(Orth.),triclinic(Tri.),and monoclinic(Mono.)phases.By micro-area ultrafast spectroscopy,we find that Orth.and Tri.phases with closerπ-πstacking exhibit co-existing coherent and incoherent SF channels while loosely stacked Mono.phase shows only incoherent SF.Furthermore,incoherent SF is thermally activated in Orth.but barrierless in Mono.and Tri.phases.Quantum mechanical calculation reveals that different electronic coupling strength in different phases leads to different SF dynamics.This study demonstrates that molecular stacking governs SF dynamics through electronic coupling,providing guidance for designing efficient SF materials via crystal structural engineering.

关 键 词：electronic couplings RUBRENE singlet fission transient absorption spectroscopy triplet pair 

分 类 号：O57[理学—粒子物理与原子核物理]