Catalyzed gelation of amorphous sulphides

Abstract

Amorphous GeS 2 and Er 3+:GeS 2 gels have been fabricated. The Er 3+ doped GeS 2 gelation rate is quicker and goes more to completion than the corresponding GeS 2 gel. This difference is attributed to the role of Er 3+ as a Lewis acid which speeds up the thiolysis rate and, in analogy to silica gels, this rate leads to a gel with a particulate (10 nm) structure compared with a polymeric structure for the undoped GeS 2 gel.