Organic near‐infrared photodetectors with photoconductivity‐enhanced performance
Siwei Zhang,
Zhenlong Li,
Jingzhou Li,
Bingzhe Wang,
Fang Chen,
Xubiao Li,
Shunjie Liu,
Jacky W. Y. Lam,
Guichuan Xing,
Jiangyu Li,
Zheng Zhao,
Feiyu Kang,
Guodan Wei,
Ben Zhong Tang
Affiliations
Siwei Zhang
Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Guangdong‐Hong Kong‐Macro Joint Laboratory of Optoelectronic and Magnetic Functional Materials The Hong Kong University of Science and Technology Kowloon Hong Kong China
Zhenlong Li
Tsinghua‐Berkeley Shenzhen Institute, Institute of Materials Science, Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China
Jingzhou Li
Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou China
Bingzhe Wang
Institute of Applied Physics and Materials Engineering, University of Macau Avenida da Universidade Taipa Macau China
Fang Chen
Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen China
Xubiao Li
Tsinghua‐Berkeley Shenzhen Institute, Institute of Materials Science, Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China
Shunjie Liu
Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China
Jacky W. Y. Lam
Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Guangdong‐Hong Kong‐Macro Joint Laboratory of Optoelectronic and Magnetic Functional Materials The Hong Kong University of Science and Technology Kowloon Hong Kong China
Guichuan Xing
Institute of Applied Physics and Materials Engineering, University of Macau Avenida da Universidade Taipa Macau China
Jiangyu Li
Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen China
Zheng Zhao
School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology The Chinese University of Hong Kong Shenzhen China
Feiyu Kang
Tsinghua‐Berkeley Shenzhen Institute, Institute of Materials Science, Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China
Guodan Wei
Tsinghua‐Berkeley Shenzhen Institute, Institute of Materials Science, Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China
Ben Zhong Tang
Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Guangdong‐Hong Kong‐Macro Joint Laboratory of Optoelectronic and Magnetic Functional Materials The Hong Kong University of Science and Technology Kowloon Hong Kong China
Abstract Organic near‐infrared (NIR) photodetectors with essential applications in medical diagnostics, night vision, remote sensing, and optical communications have attracted intensive research interest. Compared with most conventional inorganic counterparts, organic semiconductors usually have higher absorption coefficients, and their thin active layer could be sufficient to absorb most incident light for effective photogeneration. However, due to the relatively poor charge mobility of organic materials, it remains challenging to inhibit the photogenerated exciton recombination and effectively extract carriers to their respective electrodes. Herein, this challenge was addressed by increasing matrix conductivities of a ternary active layer (D–A–D structure NIR absorber [2TT‐oC6B]:poly(N,N′‐bis‐4‐butylphenyl‐N,N′‐bisphenyl)benzidin [PolyTPD]:[6,6]‐phenyl‐C61‐butyric acid methyl ester [PCBM] = 1:1:1) upon in situ incident light illumination, significantly accelerating charge transport through percolated interpenetrating paths. The greatly enhanced photoconductivity under illumination is intrinsically related to the unique donor–acceptor molecular structures of PolyTPD and 2TT‐oC6B, whereas stable intermolecular interaction has been verified by systematic molecular dynamics simulation. In addition, an ultrafast charge transfer time of 0.56 ps from the NIR aggregation‐induced luminogens of 2TT‐oC6B absorber to PolyTPD and PCBM measured by femtosecond transient absorption spectroscopy is beneficial for effective exciton dissociation. The solution‐processed organic NIR photodetector exhibits a fast response time of 83 μs and a linear dynamic range value of 111 dB under illumination of 830 nm. Therefore, our work has opened up a pioneering window to enhance photoconductivity through in situ photoirradiation and benefit NIR photodetectors as well as other optoelectronic devices.
