Ambient stable and lead-free Cs3Bi2I9-xBrx (0 ≤ x ≤ 9) perovskite films for memristor device

Abstract

In this work, we prepared lead-free Cs3Bi2I9-xBrx (x=0, 1, 2, 3, 6, 9) thin films using a green anti-solvent method under air conditions, which were used to fabricate the memristors with a structure of Al/Cs3Bi2I9-xBrx/ITO. The present memristors exhibit non-volatile and bipolar resistance switching behavior without electroforming. It is worth noting that the band gap of Cs3Bi2I9-xBrx (x=0, 1, 2, 3, 6, 9) series films were regulated by bromine doping. The switching ratio of devices changes with the films band gaps and increases from 102 to 103. The resistance state of Al/Cs3Bi2I9-xBrx/ITO devices can be maintained after 150 switching cycles and 104 seconds of reading. Moreover, the Al/Cs3Bi2Br9/ITO memristor shows excellent stability in air after 100 days or more. This study is beneficial to designing perovskite materials and regulating the performance of perovskite memristors.