Synthetic hackmanites and their optical properties – from theory to applications

Abstract

Synthetic hackmanite is a material that resembles the natural mineral, hackmanite. The structure of hackmanite, Na8Al6Si6O24(Cl,S)2, together with its simple preparation with solid state synthesis enables the doping of different ions into the hackmanite matrix, resulting in materials with a wide variety of optical properties.

The synthetic hackmanites show photoluminescence, persistent luminescence and photochromism, when excited with different wavelengths. During this thesis work, a synthetic hackmanite material showing up-conversion luminescence was also prepared.

This thesis focuses on the optical properties of synthetic hackmanites and their mechanisms. A detailed mechanism for persistent luminescence as well as photochromism in synthetic hackmanite materials is presented. Also, a new method called thermotenebrescence is introduced. This method can be used to study the energetics of photochromism.

With wide and tunable optical properties, cheap production and the fact that synthetic hackmanites do not include any heavy metals or toxic elements, many possible applications can be presented for the materials and they are listed in the end of the thesis