Crystallization mechanism and optical properties of Nd3+ doped chalcohalide glass ceramics

Nd3+-doped GeS2–In2S3–CsCl transparent chalcohalide glass ceramics containing In2.67S4 nanocrystals are prepared by melt-quenching and subsequent heating. The influence of Nd3+ doping on the In2.67S4 crystallization, the microstructure, as well as the transmission and photoluminescence spectra of glass ceramics are investigated. It is proposed that Nd3+ ions act as nucleating agents for In2.67S4 crystallization in the sample with relative low Nd3+ concentration, while a part of Nd3+ ions are believed being expelled from the crystallized regions and aggregate on the surfaces of the crystallites during crystallization when Nd3+ concentration is increased, which suppresses crystal growth, resulting in nano size and homogeneous distribution of grains, and subsequently remarkable blue-shift of the optical absorption edge of the glass ceramic. Evidently, the microhardness of chalcohalide glass is strengthened after the precipitation of In2.67S4 nanophase.