All-inorganic CsAgBiBr/Cu SCN-based photodetectors for weak light imaging  

全无机Cs2AgBiBr6/CuSCN基光电探测器及其在弱光成像中的应用

作　　者：Genghua Yan Zhong Ji Zhuowei Li Bangqi Jiang Min Kuang Xiang Cai Ye Yuan Wenjie Mai 颜庚骅;计钟;李卓伟;江邦齐;况敏;蔡祥;袁野;麦文杰(Siyuan Laboratory,Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials,Department of Physics,Jinan University,Guangzhou,510632,China;Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications,Jinan University,Guangzhou,510632,China;Guangdong Institute of New Materials,Guangdong Academy of Sciences,Guangzhou,510650,China;Department of Light Chemical Engineering,Guangdong Polytechnic,Foshan,528041,China)

机构地区：[1]Siyuan Laboratory,Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials,Department of Physics,Jinan University,Guangzhou,510632,China [2]Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications,Jinan University,Guangzhou,510632,China [3]Guangdong Institute of New Materials,Guangdong Academy of Sciences,Guangzhou,510650,China [4]Department of Light Chemical Engineering,Guangdong Polytechnic,Foshan,528041,China

出　　处：《Science China Materials》2021年第1期198-208,共11页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (51772135);the Ministry of Education of China (6141A02022516);the Fundamental Research Funds for the Central Universities (11619103);China Postdoctoral Science Foundation (2019M663376);Guangdong Province Higher Vocational Colleges & Schools Pearl River Scholar Funded Scheme (2017);the Natural Science Foundation of Guangdong Province, China (2017A020215135 and 2018A030310659);the Science and Technology Program of Guangzhou, China (201804010432)。

摘　　要：Weak light imaging has drawn more and more attention because of its promising potential for practical applications in security monitoring and space exploration. In this work, all-inorganic Cs2AgBiBr6 double perovskite-based self-powered photodetectors containing inorganic copper thiocyanate(CuSCN) as hole-transport layers(HTLs) are successfully fabricated and applied for weak light imaging,which is the first report on the weak light imaging application of all-inorganic lead-free perovskite photodetectors. CuSCN films with favorable optical property and hole extraction capability are prepared via a cost efficient and fast solvent removal method, demonstrating the potential for high-performance perovskite-based devices as transparent components. It is revealed that the band alignment of the device is effectively optimized with the presence of CuSCN HTLs,which can availably transport holes while block electrons at the Cs2AgBiBr6/CuSCN interface, resulting in remarkable improvement of photoresponse performance. The responsivity and detectivity are 0.34 A W^-1 and 1.03×10^13 Jones,respectively. In particular, the light current has a boost of almost 10 times. Furthermore, the photodetectors are integrated into a self-built light detection imaging system utilizing the focused laser scanning imaging mode. With illumination of as low as 5 nW cm^-2(405 nm), the image involving graphics and words with a size of 5 cm×5 cm can still be distinctly recognized. These results suggest the promising potential of all-inorganic perovskite-based devices for weak light detection and imaging applications.弱光成像技术在安全监测、空间勘探、医疗成像及通讯领域有着广泛的应用.光电探测器是弱光成像技术的核心元件,决定了成像系统的质量.本工作首次将硫氰酸亚铜(CuSCN)薄膜作为无机空穴传输层(HTLs)与全无机Cs2AgBiBr6双钙钛矿薄膜相结合,获得了具有优良弱光探测能力的光电探测器. CuSCN薄膜具有优异的空穴提取能力,可以有效地传输空穴并调节能带排列,从而减少载流子在Cs2AgBiBr6/CuSCN界面处的复合,使器件的光电流提升近10倍.该器件在~1 nW cm^-2的弱光下的响应度和探测率分别达到了0.34 A W^-1和1.03×10^13Jones. CuSCN薄膜还具有优异的光透过率,保证了器件的半透明特性.我们搭建了基于聚焦激光扫描成像模式的弱光成像系统,并将Cs2AgBiBr6/CuSCN异质结光电探测器集成于该系统中.采用一幅包含图形和文字的图案(尺寸为5 cm×5 cm)为成像对象.在低至5 nW cm^-2(405 nm)的辐照下,该系统依然能够输出清晰的图像.这些研究结果显示了基于Cs2AgBiBr6/CuSCN结构的全无机光电探测器在弱光探测和成像领域的巨大潜力.

关 键 词：photodetector weak light imaging all-inorganic perovskite Cs2AgBiBr6 double perovskite CuSCN inorganic hole-transport layer 

分 类 号：TN15[电子电信—物理电子学]