LUMINESCENCE MECHANISM STUDY OF A POTENTIAL SCINTILLATION CRYSTAL YBa3B9O18

The luminescence mechanisms of a potential scintillation crystal YBa 3 B 9 O 18 were investigated by experimental methods. As a first step, the optical band gap energy Eg was estimated to be 7.3 eV from the optical absorption spectrum and vacuum ultraviolet excited luminescence spectra. The X-ray photoelectron spectroscopy measured in the valence region coincided with the first principle energy band calculation. Based on the analysis of valence band structure and vacuum ultraviolet excited luminescence spectra the origins of emission bands of YBa 3 B 9 O 18 were studied. The intrinsic luminescence of YBa 3 B 9 O 18 was attributed to the radiative decay of self-trapped excitons. The elucidation of the luminescence mechanism provides a physical picture on the property-structure correlation and may help to accelerate the applications of the potential scintillation crystal.