Advances in Ce3+ doped Y1±xAlO3 (x≠0) single crystal perovskite scintillators through nonstoichiometric engineering

The influence of nonstoichiometric engineering on the scintillation properties of Ce3+ doped yttrium aluminum perovskite (YAP:Ce) crystals was investigated. Crystals with slight yttrium excess (Y1.004AlO3:Ce), yttrium deficiency (Y0.994AlO3:Ce), and stoichiometric composition (YAlO3:Ce) were synthesized using the micro-pulling down method. Structural characterization confirmed crystallization in the pure orthorhombic Pnma space group for all compositions. Optical absorption spectroscopy revealed an extensive background in the nonstoichiometric crystals due to the increased degree of light scattering centers associated with the defects. The photoluminescence excitation and emission spectra of Ce3+ ions were unaffected by nonstoichiometry. However, the scintillation decay kinetics and light yield exhibited marked improvements in the Y1±xAlO3:Ce (x≠0) crystals. The light yield increased by 22 % and 15 % and the slower component of the decay accelerated from 171 ns to 106 and 131 ns compared to the stoichiometric crystal. Thermoluminescence glow curves revealed that nonstoichiometry significantly altered the concentrations of antisite defects and oxygen vacancies. The EPR spectroscopy investigations revealed a correlation between the Ce3+ ions concentration and the degree of nonstoichiometry. Strategic engineering of nonstoichiometry in Y1±xAlO3:Ce (x≠0) scintillators may have provided an effective approach to optimizing scintillation performance.