Nonvolatile Rewritable Photomemory Arrays Based on Reversible Phase‐Change Perovskite for Optical Information Storage

Abstract The high transmission speed of optical signals and their application in optical computation have created a growing demand for photon‐programmed memory devices. Rather than using electrical pulses to store data in one of two states, the photomemory (PM) devices exploit the optical stimulation to store the light information. In this work, the application of a nonvolatile rewritable PM array using the photochromic inorganic perovskite CsPbIBr₂ grown by a vapor‐deposition process is demonstrated. Reversible phase transitions between orthorhombic (δ) and cubic (α) phases are achieved in CsPbIBr₂ films through laser‐induced heat and moisture exposure. The PM pixels in an optically absorbing perovskite phase exhibit ≈50‐fold photoresponsivity as large as those in a transparent‐colored non‐perovskite phase. Storing optical data are achieved by heating pixels through a near‐infrared laser, while moisture exposure is used to erase the stored information. The nonvolatile PM array exhibits great write‐read‐erase cycle endurance and data retention capability without obvious performance degradation after storage in air for one week. This work demonstrates the promising application of vapor‐deposited inorganic perovskite for optical information storage and the unique potential of them for use in optical switches, tunable metasurfaces, and many other applications.