全真空蒸发法制备Cs₃Bi₂I₉全无机类钙钛矿光电探测器

Preparation of Cs₃Bi₂I₉ All-Inorganic Perovskite-Like Photodetectors via Full Vacuum Evaporation Technique

摘要: 光电晶体管是一种三端光电探测器，由于栅极的放大作用，通常比光电二极管具有更高的光电流增益。本文采用全真空蒸发法制备了酞菁铜(CuPc)和Cs₃Bi₂I₉ (CBI)异质结的广谱光电晶体管。由于CuPc和CBI的紫外-可见互补吸收，该器件在三种不同类型的可见光照明下均表现出优异的性能。实验结果表明，该有机/钙钛矿异质结活性层结构具有相容性好、工艺简单等特点。同时，利用钙钛矿材料优越的光吸收特性和异质结界面强激子解离效率，CuPc/CBI-OPT具有比CuPc基准器件更高的光响应性、光敏性、比检出率和更低的工作电压。稳定性测试表明，CuPc/CBI-PT在没有任何封装的情况下在空气中储存360 h后，在660 nm光照下仍能获得0.73 A/W的光响应性。这表明有机/钙钛矿异质结PT可能是制备高性能光电探测器的良好选择。

Abstract: A phototransistor is a three-terminal photodetector that typically exhibits higher photocurrent gain compared to a photodiode, attributed to the amplification effect of the gate. In this study, we have successfully fabricated a broad-spectrum phototransistor featuring a copper phthalocyanine (CuPc) and cesium trithioindate (Cs₃Bi₂I₉, CBI) heterojunction via a full vacuum evaporation process. Benefiting from the complementary UV-visible absorption properties of CuPc and CBI, the device demonstrates superior performance under various visible light illumination conditions. Experimental findings indicate that the organic/perovskite-like heterojunction active layer structure possesses excellent compatibility and a straightforward fabrication process. Leveraging the exceptional light absorption capabilities of perovskite-like materials and the efficient exciton dissociation at heterojunction interfaces, the CuPc/CBI phototransistor (CuPc/CBI-PT) achieves enhanced photoresponsivity, sensitivity, specific detection rate, and reduced operating voltage compared to reference CuPc devices. Stability assessments reveal that the CuPc/CBI-PT maintains a photoresponsivity of 0.73 A/W at 660 nm after 360 hours of air exposure without encapsulation. These results suggest that organic/perovskite-like heterojunction phototransistors may serve as a promising candidate for high-performance photodetectors.