Interface terminal group regulated organic phototransistors with tunable persistent and switchable photoconductivity  

作　　者：Di Xue Yingying Zhang Weijie Gong Yao Yin Zi Wang Lizhen Huang Lifeng Chi 

机构地区：[1]Institute of Functional Nano&Soft Materials(FUNSOM),Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University,Suzhou,215123,China [2]Gusu Laboratory of Materials,Suzhou,215123,China [3]Macao Institute of Materials Science and Engineering(MIMSE),MUST-SUDA Joint Research Center for Advanced Functional Materials,Macao University of Science and Technology,Taipa,Macao,999078,China

出　　处：《Science China Chemistry》2022年第12期2567-2575,共9页中国科学（化学英文版）

基　　金：supported by the National Key Research and Development Program of China (2018YFE0200700);the National Natural Science Foundation of China (52173176,51773143,51821002);the Collaborative Innovation Center of Suzhou Nano Science&Technology;the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD);the 111 Project

摘　　要：With both light detection and intrinsic amplification functions,organic phototransistors have demonstrated promising applications,including photodetection and photomemory.To achieve excellent photoresponse and superior photogain,a common and effective strategy is to modulate the trapping effect with the purpose of reducing recombination or prolonging the lifetime of the photogenerated charge carriers.However,introducing trapping sites delicately is challenging and might sacrifice the response rate together with a typical persistent photoconductivity.Here,we demonstrate a facile strategy for achieving high photo-responsive organic phototransistors with both persistent and switchable photoconductivity features via interface terminal group regulation.By varying the terminate groups of self-assembled monolayer(SAMs)from the strong electron withdrawing group-F,neutral−CH_(3) to electron donating−NH_(2) on the dielectric surface,we realize both minority carrier trapping and majority carrier trapping in the organic phototransistor based on the C8-BTBT active layer.The electron withdrawing effect of F significantly enhances the minority carrier trapping process and yields a high photoresponsivity with a long-lasting persistent photoconductivity.In contrast,the electron donating group−NH_(2) with a distinct majority carrier trapping ability causes switchable photoconductivity so that the photocurrent can rise pronouncedly and fully decay along with light on/off.Attractively,both cases can deliver high performance with photoresponsivities higher than 104 A W^(−1) together with a photosensitivity in the level of 107 and a detectivity of approximately 10^(15)–10^(16) Jones.Such a tunable,excellent photoresponse property enables the convenient exploration of organic phototransistors to satisfy different application requirements.

关 键 词：organic phototransistor surface modification TRAPPING persistent photoconductivity 

分 类 号：TN36[电子电信—物理电子学]