Impact of amorphization on the luminescence and UVC upconversion efficiency of LaAlO₃:Pr³⁺ materials

In this work, we present a comparative study of LaAlO₃:Pr³⁺ materials in both crystalline and amorphous specimens, exploring how structural differences influence their optical properties. Polycrystalline powders with a perovskite structure were synthesized via high-temperature solid-state reaction, and then transformed into spherical amorphous forms (∼1 mm diameter) using the aerodynamic levitation method with CO₂ laser heating. Comprehensive structural (XRD, SEM, and EDS) and spectroscopic (emission, excitation, and decay time) analyses were performed. Particular focus was given to visible-to-ultraviolet upconversion in LaAlO₃:2%Pr³⁺ samples under 444 nm laser excitation. The study revealed distinct differences in luminescence behavior between the crystalline and amorphous phases, with the former showing enhanced upconversion efficiency. These results underline the critical role of local structural environments in tuning the photonic properties of Pr³⁺-doped materials, offering valuable insights for the design of next-generation optical devices with applications in photonics, optoelectronics, and UV-based technologies.