Improved performance of CH3NH3PbI3 based photodetector with a MoO3 interface layer

Abstract Planar CH 3 NH 3 PbI 3 perovskite based photodetectors are fabricated by a facile and low-cost one-step method. The devices show broad spectral photoresponse from the ultraviolet to whole visible region and the performance can be significantly improved by the introduction of a bipolar transporting MoO 3 interface layer between CH 3 NH 3 PbI 3 film and Au electrode. The photocurrent of the device with an optimized MoO 3 layer is about twice that of the reference device without MoO 3 layer, which results in a high ON/OFF current ratio of 5.9 × 10 3  at 5 V. Besides, slightly increased photoresponse speed is also found in the optimized device with rise time and decay time of 21.6 and 9.9 ms, respectively. The improvement can be attributed to the improved hole and electron collection efficiency and the quickly filled in or emptied trap states at the CH 3 NH 3 PbI 3 /Au interface due to the introduction of the bipolar transporting MoO 3 layer.