Realization of the transition from an indirect band gap to a direct band gap through halogen regulation in the Cs-Ag-X system

Abstract

Scintillation crystals need to have a direct band gap. Here, two new optical crystals, CsAgClI and Cs₂AgBr₂I, were obtained through halogen regulation, achieving the transition from an indirect band gap (CsAgCl₂) to direct band gaps. This work enriches the structural chemistry of the Cs-Ag-X system, and is conducive to the exploration of new scintillation crystals.