A zeolite-free synthesis of luminescent and photochromic hackmanites

In order to further boost their potential applications as optical materials by improving structural and compositional tuneability, hackmanites (Na-8(AlSiO4)(6)(Cl,S)(2)) exhibiting multiple optical properties such as photoluminescence, persistent luminescence, and tenebrescence, were synthesised in a solid-state reaction using simple starting materials. All materials with the desired structure showed both blue-white photoluminescence typical of synthetic hackmanite, and white persistent luminescence, which have not previously been reported for hackmanites synthesised using zeolite-free methods. The typical orange luminescence of disulfide seen in natural hackmanites after 365 nm excitation was not observed. Samples made under optimised synthesis conditions of heating at 900 degrees C for 72 h followed by a reduction also showed purple tenebrescence typical of hackmanite. The optical energy storage properties of hackmanites made without zeolite A, as well as potential methods for tuning them, are discussed for the first time. These materials have previously been investigated for potential as multifunctional optical markers and for optical multiplexing; these results further the understanding of hackmanites and bring them one step closer to commercial viability as optical materials. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

Hackmanites with multiple optical properties were synthesized through solid-state reaction, showing typical blue-white photoluminescence and white persistent luminescence. The study also discussed optical energy storage properties and tuning methods for hackmanites synthesized without zeolite A for the first time, advancing their potential applications in optical materials.