Engineering aluminosilicate's photochromism by quantum chemistry

Sodalite-based photochromic minerals represent a potentially new family of inorganic photochromes. It was previously proven that the change in the color of these minerals is based on a photo-induced electron transfer from a sulfur-based impurity to a chlorine vacancy, leading to the formation of a trapped electron. In parallel, several groups have shown that it is possible to artificially synthesize these minerals and to tune the chemical composition from the native one (Na-8[AlSiO4](6)Cl-2). In this study, we use an assessed quantum chemical method (based on periodic DFT calculations and TD-DFT calculations on an embedded cluster) to predict the influence of the chemical modification of sodalite on the photochromic properties of the material considering the general composition C-8[ABO(4)](6)X-2 (A = Si, Ge; B = Al, Ga; C = Na, K; X = Cl, Br, I). The aim of this work is to pave the way for the design of artificial sodalites for specific applications.