Direct Laser Write‐Read‐Erase in a Functional Molecular Phase Change Material–Polymer Nanocomposite Thin Film

Abstract

Phase change materials based on organics and salt hydrates with large latent heats of transition are used extensively in energy storage systems; those based on low melting alloys exhibiting electrical/optical characteristics switching with amorphous‐crystalline (A ↔ C) transformations are of major interest in information storage devices. The direct laser write‐read‐erase is reported using a functional molecular phase change material. Facile and reversible A ↔ C transformations with concomitant switching of fluorescence emission color and intensity are demonstrated in polymer thin films doped with a diaminodicyanoquinodimethane based fluorophore using thermal operations as well as laser irradiation. In the mask‐less direct write‐erase process developed, the laser power and irradiation time are tuned to write and erase; the reading is carried out by exploiting the characteristic fluorescence signature. This work opens up a novel avenue to develop sensors and encryption systems exploiting organic molecule based optical materials encapsulated in polymer thin films.