Upconversion luminescence of Nd3+–Pr3+ codoped CsCl modified Ge–Ga–S glasses and the relevant energy transfer mechanism

The visible upconversion luminescence properties of Pr3+/Nd3+ co-doped CsCl modified Ge–Ga–S glasses are investigated. Enhanced emissions from Pr3+ ions via energy transfer from Nd3+ ions are observed at 488, 678 and 729 nm. The possible mechanisms accounting for the enhanced Pr3+ emissions and upconversion emissions of Nd3+, i.e. energy transfer upconversion (ETU) are discussed. The results show that the CsCl modified Ge–Ga–S glasses are promising luminescent materials for solid state lasers and displays, etc.