Cathodoluminescence and microstructural analysis of amorphous yttrium-aluminum-borate luminescent powders

Abstract

We present the cathodoluminescence (CL) and microstructural analysis of amorphous yttrium aluminum/aluminium borate (a-YAB) luminescent powders synthesized by polymeric precursor (PP) and sol-gel (SG) based wet-chemical methods. The a-YAB powders exhibit bright photoluminescence tunable from intense blue to white chromaticity region depending on their calcination temperature. Here, the influence of calcination temperature on CL and microstructural properties of the a-YAB powders has been investigated. The a-YAB powders showed weak but homogeneous CL. Within the optimum calcination temperatures for photoluminescence (650–740 °C for PP and 450–600 °C for SG series), the CL observed to be more intense for powders synthesized at higher calcination temperature. The microstructure analysis revealed that the SG series powders calcined below 570 °C exhibit intraparticle chemical inhomogeneity, whereas no such inhomogeneity could be seen in PP series powders, owing to their higher calcination temperatures. Nevertheless, both series exhibit similar luminescence broadening with calcination temperatures despite these microscopic differences, revealing that the luminescence broadening does not depend on the chemical properties at the microscopic level, but is controlled by more intrinsic effects on the luminescent centers or its immediate surrounding as a function of calcination temperature.