Trap-Controlled Sodalites with High Photochromic Contrast for Decoration Applications

Abstract

Motivated by their variable chromatic transformations and remarkable thermal stability, photochromic materials derived from sodalite (Na8(AlSiO4)6Cl2) have been proposed for various applications such as optical anti-counterfeiting and radiation dosimetry. Nonetheless, the utilization of these optical materials is significantly constrained by the intricate synthesis process and weak photochromic contrast. Herein, a one-step microwave-assisted solid-state method is adopted to prepare sodalites and optimize the photochromic performance. The results show that the sample can be synthesized through only 16-minute microwave radiation, greatly simplifying the preparation process. Notably, the maximum photochromic contrast of sodalite is enhanced from 13.8% to 26.9% through the partial substitution of Cl with S ions. In addition, optical spectroscopy and electron spin resonance experiments are presented to investigate the influence of traps on the photochromic behavior. It was found that the photochromic behavior in sodalites is mainly determined by traps with an energy depth around 0.788 eV. The activation energy of these traps is determined by the host and corresponding preparation approach. Finally, sodalite-based compounds are fabricated into fibers for clothing decoration demonstration. This work not only provides a facile method for the synthesis of sodalite-based photochromic materials, but also gives insight into the trap-involved photochromic mechanism.