Improving photovoltaic effect of inorganic perovskite by resistive switching using various electrode materials

Resistive switching (RS) between high resistance state (HRS) and low resistance state (LRS) is generally attributed to the redistribution of defects under the application of electric field, and the performance is sensitive to the electrode materials. In this paper, CsPbBr3 layer was deposited on F-doped SnO2 (FTO) glass substrates with or without TiO2 layer, followed by the deposition of Ag or Ni layer as top electrode by pulsed laser deposition. Bipolar resistive switching behavior was observed in the devices of both electrodes, but the ON/OFF ratio was much larger for Ni electrode. TiO2 layer, as electron transport layer in solar cell, had little influence on the RS behavior. The mechanism has been demonstrated to be the formation and rupture of conductive filaments due to the migration of Br vacancies under electric field. The improved ON/OFF ratio for Ni electrode was due to the much larger resistance in HRS. RS provides an effective manipulation method to control the defects, and the influence on the photovoltaic effect was studied. Linear I–V curves were observed in LRS with nearly zero open circuit voltage, which was due to the shunting effect of conductive filaments. Both open circuit voltage and short circuit current were improved in HRS, compared with the initial state, which was attributed to the accumulation of defects in conductive filaments, leading to the decrease of recombination centers of electron-hole pairs in the CsPbBr3 layer.