Exploring the potential of Tb and Bi-doped LaF3 as a UV absorber

Abstract Lanthanide-based nanophosphors are finding significant applicability in various fields such as LED, solar spectral convertors, lasers, and biological sensors, owing to their superior stability and luminescence properties. However, their function as a UV protector has not evolved, possibly because of their limited absorption cross-section in the UV spectral region. Hence, to overcome this limitation, in this work, a strategy to utilize Bi 3+ ion as a co-dopant in LaF 3 :Tb 3+ nanophosphor has been devised. These nanophosphors with an uniform morphology and narrow particle size distribution were synthesized using the hydrothermal method. Luminescence mechanism involving energy transfer from Bi 3+ to Tb 3+ was investigated. The excitation spectrum of a LaF 3 nanophosphor, co-doped with Bi and Tb, reveals distinct absorption bands. Absorption ascribed to Bi 3+ characterizes the UV range between 220 and 275 nm, whereas Tb 3+ is associated with absorption in another UV range spanning 280 to 380 nm. This shows the potential applicability of the Bi and Tb co-doped LaF 3 nanophosphors as a UV absorber. The cytotoxicity of these nanophosphors was tested on HaCaT cells, indicating their potential applicability in the healthcare field.