Optical properties of oxynitride powders

(Oxy)nitride materials have attractive properties directly related to the role played by nitrogen. A commonly used synthesis method consists of the thermal nitridation of an oxide precursor in flowing ammonia. As a consequence of the anionic N3-/O2- substitution results an increase in the covalent character, illustrated by a shift of the absorption edge towards higher wavelength values. Thus, oxynitrides offer potentialities as optical materials in the domain of colored pigments, UV absorbers and visible-light photocatalysts. (C)2009 The Ceramic society of Japan. All rights reserved.