Effect of annealing on lattice engineering and luminescence in LYSO:Ce scintillators

Abstract

This study systematically investigated the effect of annealing process parameters (temperature range of 1100–1300 °C, time of 6–12 h) on the microstructure and optical properties of cerium doped yttrium lutetium silicate (LYSO:Ce) single crystals. Large-sized LYSO:Ce single crystals (diameter of 114 mm, length of 265 mm) with uniform composition and macroscopic integrity were successfully prepared using the Czochralski method. By comprehensively utilizing analytical techniques, the evolution mechanism of lattice defects during annealing and their synergistic effects on the local environment of Ce³⁺ luminescent centers were systematically elucidated. The study suggests that the sample annealed at 1200 °C for 10 h exhibited the highest photoluminescence quantum yield (PLQY) of 66.01%, primarily attributed to the effective reconstruction of oxygen vacancy clusters and enhanced lattice order. Raman spectra and thermoluminescence results indicate that appropriate annealing treatment helps optimize trap energy level distribution and promote radiative recombination of charge carriers. This work provides a theoretical basis and experimental support for the process design of LYSO:Ce crystal defect engineering and promotes the application progress of this type of scintillation crystal in medical imaging and high-energy physics detection. Moreover, the optimized annealing treatment significantly enhanced the scintillation performance, improving the light output by ∼52% at 511 keV and ∼43% at 1275 keV, while substantially improving the energy resolution from 14.5% to 8.0% at 1275 keV, demonstrating its potential for high-performance radiation detection applications.