Optoelectronic processes of metal-organic perovskite photodetectors based on interdigitated comb of electrodes

Metal-organic hybrid perovskites are a new class of semiconducting materials currently yielding high-performance solar cells. They are also attractive for fabrication of photodetectors, which are based on similar operating principles. In this work a comprehensive analysis of MAPbI3 perovskite photoconductive photodetectors made on interdigitated combs of electrodes of different metals were presented. The role of the oxide layer in the performance of planar perovskite photodetectors formed on interdigitated metal electrodes is demonstrated. The oxide layer enhances the photocurrent gain by order of magnitude by hampering hole extraction and increasing its residence in perovskite layer time. Naturally formed CrOx layer on Cr electrodes enables achievement of about 360 times photocurrent enhancement and about 5 ms response time. Formation of a TiO2 layer on Pt electrodes also enables the gain enhancement form 19 to 150 times. Based on the relatively long response time, it has been suggested that ion migration plays an essential role in the gain enhancement and explanation of the gain mechanism is proposed. The achieved high photodetector sensitivity, a suggested gain enhancement approach and obtained better understanding of the photocurrent gain mechanism open a way towards the further development of cheap and easily producible planar perovskite detectors based on interdigitated electrode arrays