Covalent Functionalization of Black Phosphorus Nanosheets with Photochromic Polymer for Transient Optoelectronic Memory Devices

Abstract

AbstractHow to erase sensitive data stored on memory devices quickly in an emergency has become a critical issue that needs to be addressed. Using BP‐BIBB as a key template for atom transfer radical polymerization, which is prepared by the reaction of p‐hydroxyphenyl‐functionalized black phosphorous nanosheets (C6H4OH‐BP) with 2‐bromoisobutyryl bromide (BIBB), a highly soluble poly[4‐(4‐(3,3,4,4,5,5‐hexafluoro‐2‐(2‐methyl‐5‐phenylthiophen‐3‐yl)cyclopent‐1‐en‐1‐yl)‐5‐methylthiophen‐2‐yl)phenyl methacrylate] (PHPM)‐covalently grafted BP derivative, hereafter abbreviated as PHPM‐g‐BP, is synthesized in situ. PHPM is a typical photochromic polymer that emits blue light under UV irradiation, while showing pale yellow under visible light illumination. By using PHPM‐g‐BP as an active layer, an as‐fabricated transient optoelectronic memory device exhibits a nonvolatile rewritable memory effect under UV irradiation, with an ON/OFF current ratio of 3.6 × 103, a turn‐on voltage of 1.60 V, and a turn‐off voltage of −1.41 V. Upon visible light illumination for 10 s, all the information stored in the device is erased quickly. The observed device current drops down from 10−3 to 10−8 A rapidly.