Ln3+ (Ln=Ce, Tb, Dy) and Hf doping of LuI3 powders – A material and spectroscopic study

Abstract The moisture sensitivity of LuI 3 :Ce,Hf and luminescent properties of undoped LuI 3 and LuI 3 :M (M=Ce 3+ , Tb 3+ , Dy 3+ ) powders were investigated. The possibility of improving the air and moisture stability of LuI 3 :Ce by Hf doping was tested. It was proven that the Hf contribution to the LuI 3 :Ce stability is very limited and is insignificant to render LuI 3 :Ce scintillator powders suitable for applications. Photoluminescence results of LuI 3 without dopants added on purpose showed luminescence due to a plurality of rare-earth elements׳ impurities. Two types of self-trapped luminescence were found. Energy transfer between host lattice, self-trapped excitons and rare-earth ions was investigated.