VUV spectroscopy of lanthanide doped fluoride crystals K2YF5

Abstract

K2Y0.99Ln0.01F5 (Ln = Ce, Eu and Sm) single crystals have been synthesized by the hydrothermal technology. The optical properties of Ce3+ and Eu3+ ions doped into K2YF5 matrix have been studied under excitation in the deep UV and vacuum UV (VUV) region. The obtained data from excitation spectra and Dorenbos models have been used to predict the energies of the f-d and charge transfer transitions as well as the energy levels location of divalent (Ln2+) and trivalent (Ln3+) lanthanide ions within the band gap of K2YF5. In particular, the f-d and charge-transfer transitions of Sm3+ in the luminescence excitation spectrum of K2YF5:Sm3+ have been identified. The host referred binding energy (HRBE) and vacuum referred binding energy (VRBE) schemes have been constructed for Ln2+ and Ln3+ ions doped K2YF5 crystal which were used for the analysis of possible applications of K2YF5 doped with Ln3+ ions as thermoluminescence materials.