Thermally-induced ionization of the Ce3+ excited state in SrHfO3 microcrystalline phosphor

Abstract We measured temperature dependences of emission spectra, prompt nanosecond decays and millisecond delayed recombination decays for the Ce 3+ center in the SrHfO 3 (SHO) host. We characterized two samples with 0.1% and 5%Ce prepared by the acetate and citrate combustion and solid state reaction, respectively. The decrease of nanosecond decay times above approximately 220 and 260 K, respectively, is due to thermal ionization of 5d 1 excited state of the Ce 3+ center. Energy barrier of 300 meV, governing this process, is calculated for both the 0.1% and 5%Ce:SHO samples. Thermoluminescence glow curve measurement after X and UV (310 nm) irradiation at RT provides another support for the 5d 1 excited-state ionization of Ce 3+ in the SHO host.