Huang Zhenqiang, Zhong Zhiming, Peng Feng, Ying Lei, Yu Gang, Huang Fei, Cao Yong
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
South China Institute of Collaborative Innovation, Dongguan 523808, China.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):1027-1034. doi: 10.1021/acsami.0c18260. Epub 2020 Dec 22.
Interfacial modification between the electrode and the overlying organic layer has significant effects on the charge injection and collection and thus the device performance of organic photodetectors. Here, we used copper(I) thiocyanate (CuSCN) as the anode interfacial layer for organic photodetector, which was inserted between the anode and an organic light-sensitive layer. The CuSCN layer processed with ethyl sulfide solution presented similar optical properties to the extensively used anode interlayer of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), while the relatively shallow conduction band of CuSCN resulted in a much higher electron-injection barrier from the anode and shunt resistance than those of PEDOT:PSS. Moreover, the CuSCN-based device also exhibited an increased depletion width for the PEDOT:PSS-based device, as indicated by the Mott-Schottky analysis. These features lead to the dramatically reduced dark current density of 2.7 × 10 A cm and an impressively high specific detectivity of 4.4 × 10 cm Hz W under -0.1 V bias and a working wavelength of 870 nm. These findings demonstrated the great potential of using CuSCN as an anode interfacial layer for developing high-performance near-infrared organic photodetectors.
电极与覆盖的有机层之间的界面修饰对电荷注入和收集以及有机光电探测器的器件性能具有显著影响。在此，我们使用硫氰酸亚铜（CuSCN）作为有机光电探测器的阳极界面层，将其插入阳极与有机光敏层之间。用乙硫醇溶液处理的CuSCN层呈现出与广泛使用的聚（3,4 - 乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT:PSS）阳极中间层相似的光学性质，而CuSCN相对较浅的导带导致其从阳极的电子注入势垒和分流电阻比PEDOT:PSS的要高得多。此外，如莫特 - 肖特基分析所示，基于CuSCN的器件相对于基于PEDOT:PSS的器件还表现出耗尽宽度增加。这些特性导致暗电流密度显著降低至2.7×10 A/cm²，并且在 - 0.1 V偏压和870 nm工作波长下具有高达4.4×10¹² cm Hz¹/² W⁻¹的比探测率。这些发现证明了使用CuSCN作为阳极界面层来开发高性能近红外有机光电探测器的巨大潜力。
