原子级化学反应促进可弱光探测有机光电倍增探测器的外量子效率超过10^(8)%  

Atomic-level chemical reaction promoting external quantum efficiency of organic photomultiplication photodetector exceeding 10°%for weak-light detection

作　　者：石林林 朱益志 李国辉 冀婷 王文艳 张叶 吴宇坤 郝玉英 王开鹰 袁俊 邹应萍 Beng S.Ong 朱福荣 崔艳霞 Linlin Shi;Yizhi Zhu;Guohui Li;Ting Ji;Wenyan Wang;Ye Zhang;Yukun Wu;Yuying Hao;Kaiying Wang;Jun Yuan;Yingping Zou;Beng S.Ong;Furong Zhu;Yanxia Cui(College of Optoelectronics,Key Laboratory of Interface Science and Engineering in Advanced Materials,Key Laboratory of Advanced Transducers and Intlligent Control System of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,Taiyuan 030032,China;College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China;Department of Physics,Research Centre of Excellence for Organic Electronics,Institute of Advanced Materials,Hong Kong Baptist University,Hong Kong,China Department of Microsystems,University of South-Eastern Norway,Horten 3184,Norway;College of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China)

机构地区：[1]College of Optoelectronics,Key Laboratory of Interface Science and Engineering in Advanced Materials,Key Laboratory of Advanced Transducers and Intlligent Control System of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China [2]Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,Taiyuan 030032,China [3]College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China [4]Department of Physics,Research Centre of Excellence for Organic Electronics,Institute of Advanced Materials,Hong Kong Baptist University,Hong Kong,China Department of Microsystems,University of South-Eastern Norway,Horten 3184,Norway [5]College of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China

出　　处：《Science Bulletin》2023年第9期928-937,M0004,共11页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China (U21A20496,61922060,62205235,62204157,61805172,12104334,62174117,and 61905173);the Graduate Innovation Project of Shanxi Province (2020BY117);the Key Research and Development (International Cooperation)Program of Shanxi Province (201803D421044);the Natural Science Foundation of Shanxi Province (20210302123154 and 20210302123169);Research Project Supported by Shanxi Scholarship Council of China (2021-033);Research Project Supported by Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering (2021SX-FR008 and 2022SX-TD020);Introduction of Talents Special Project of Lvliang City (Rc2020206,Rc2020207);Transformation Cultivation Project of University Scientific and Technological Achievements of Shanxi Province (2020CG013);the Key Research and Development Program of Shanxi Province (202102150101007);the support from the Research Grants Council,University Grants Committee,Hong Kong,General Research Fund (12303920);SZ-HK-Macao Science and Technology Plan Project (SGDX2020110309540000);Guangdong Basic and Applied Basic Research Fund (2022A1515010020)。

摘　　要：外量子效率远大于100%、低成本、溶液法制备的倍增型有机光电探测器(PM-OPDs)引起广泛关注.但该类器件因阳极欧姆接触带来暗电流的恶化,使其弱光探测并不理想.基于此,本文提出了原子级化学反应改善PM-OPDs暗电流及弱光探测策略,进而带来器件综合性能的显著提升.具体地,本文利用原子层沉积技术在空穴传输层PEDOT:PSS与活性层P3HT:PC71BM(100:1)之间引入0.8 nm厚的Al_(2)O_(3)界面层,通过对薄膜拉曼、XPS及FT-IR性能进行表征,发现原子级厚度的Al_(2)O_(3)可与PEDOT:PSS的化学基团发生反应,调节PEDOT:PSS的功函数,进而在阳极一侧形成肖特基接触.通过与阴极肖特基接触协同,器件在保持高倍增行为的同时,暗电流显著降低.最终,器件的弱光探测性能有所改善,相比于标准器件(可探测64 nW/cm^(2)弱光),Al_(2)O_(3)修饰器件可探测低至2.5 nW/cm^(2)的弱光,且相应的外量子效率和响应率分别达到4.31×10^(8)%,1.85×10^(6)A/W,达到目前报道PM-OPDs的最优值.此策略在新型柔性电子产品及医学成像领域具有很好的应用前景.Low-cost,solution-processed photomultiplication organic photodetectors(PM-OPDs)with external quantum efficiency(EQE)above unity have attracted enormous attention.However,their weak-light detection is unpleasant because the anode Ohmic contact causes exacerbation in dark current.Here,we introduce atomic-level chemical reaction in PM-OPDs which can simultaneously suppress dark current and increase EQE via depositing a 0.8 nm thick Al_(2)O_(3) by the atomic layer deposition.Suppression in dark current mainly originates from the built-in anode Schottky junction as a result of work function decrease of hole-transporting layer of which the chemical groups can react chemically with the bottom surface of Al_(2)O_(3) layer at the atomic-level.Such strategy of suppressing dark current is not adverse to charge injection under illumination;instead,responsivity enhancement is realized because charge injection can shift from cathode to anode,of which the neighborhood possesses increased photogenerated carriers.Consequently,weak-light detection limit of the forwardly-biased PM-OPD with Al_(2)O_(3) treatment reaches a remarkable level of 2.5 nW cm^(-2),while that of the reversely-biased control is 25 times inferior.Meanwhile,the PM-OPD yields a record high EQE and responsivity of 4.31×10^(8)%and 1.85×10^(6)A W^(-1),respectively,outperforming all other polymer-based PM-OPDs.

关 键 词：外量子效率 肖特基接触 弱光探测 原子级 暗电流 柔性电子 欧姆接触 空穴传输层 

分 类 号：TN15[电子电信—物理电子学]