Upconversion luminescence and kinetics in Er3+:YAlO3 under 652.2Â nm excitation

Ultraviolet and visible upconversion properties of Er3+ in YAlO3 were investigated following 652.2 nm excitation of the multiples 4F9/2. The luminescence and excitation spectra were recorded. Ultraviolet (326-342 and 354-359 nm), violet (405-420 nm), blue (436-442 nm) and green (525-575 nm) upconversion and infrared downconversion luminescence were simultaneously observed. The intense green luminescence corresponds to the emissions from the thermal coupled 4S3/2 and 2H11/2 bands and 2G9/2 level. Energy transfer upconversion processes were proposed to explain the upconversion phenomena. The luminescence kinetics was discussed in detail by the analyses of fluorescence decay curves.