Abstract Chalcohalide glasses in the CdSe–AgI–As 2 Se 3 system were synthesised and characterised for the first time. The glass-forming range for (CdSe) x (AgI) 0.5 − x /2 (As 2 Se 3 ) 0.5 − x /2 compositions was found to be limited to x ≤ 0.20 without any significant change in the glass transition temperature but with two sub-regions with decreased ( x ≤ 0.05) and increased ( x ≥ 0.10) crystallisation ability. The glasses belong to ionic conductors and their conductivity decreases drastically with increasing x accompanied by simultaneous increase of the activation energy. The observed changes in the ionic transport properties are caused by two independent mechanisms: (i) an exchange reaction, CdSe + 2AgI ⇄ CdI 2 + Ag 2 Se, taking place in the glass-forming melt, and (ii) blocking of Ag + preferential conduction pathways by cadmium.
Mohammad Kassem, D. Le Coq, M. Bokova
Solid State Ionics