Device Physics of a Metal Halide Perovskite Diode: Decoupling of the Bulk from the Interface

Metal halide perovskite diodes have emerged as excellent devices for applications in a range of next-generation optoelectronic and electronic technologies. However, an accurate understanding of the device operation is still lacking. The reasons are that the ionic and electronic processes in the bulk are complex, and their coupling with the charge carrier dynamics at the interface is formless. Here, the bulk ionic and electronic dynamics decouple from the interfacial effects by a 20 nm bismuth layer inserted between the gold electrode and the perovskite layer. As a result, the diode shows a novel bidirectional photocurrent with a plastic hysteresis zone. Then, we developed a simple ion-involved photodiode model based on the bulk processes and reproduced the peculiar photocurrent. The work constitutes the basic understanding of the device physics of the perovskite diode, and the findings could facilitate the ultimate device design for applications such as data processing and storage.