Rational design of bi-functional RE3+ (RE = Tb, Ce) and alkali metals (M+ = Li, Na, K) co-doped CaAl2O4 nanophosphors for solid state lighting and advanced forensic applications

Abstract

Novel CaAl2O4:Tb3+, Ce3+, M+ (M+ = K, Na, Li) nanophosphor was fabricated by bio-inspired solution combustion route by using lemon juice as a fuel. PXRD profiles endorse monoclinic phase in all samples irrespective of the dopants. The photoluminescence emission spectra exhibit peaks in the range at ˜450–650 nm, which were attributed to 5D4→7FJ (J=6, 5, 4 and 3) transitions of Tb3+ ions. With increases of concentration of co-dopant Ce3+ ions, the rate of energy transfers from Ce3+ to Tb3+ ions also increase, which may lead to enhanced emission. Moreover, the two-fold enhancement of the PLE intensity was noticed in M+ co-doped CaAl2O4: Tb3+, Ce3+ nanophosphor. The high purity green color emission was confirmed from photometric characterization. The visualized LFPs using optimized sample exhibit high sensitivity, selectivity without background hindrance. Aforementioned results confirm that the prepared nanophosphor might be a classical material for WLEDs and advanced forensic applications.