White light emission characteristics of Tb3+ and Sm3+ co-doped CaYAlO4 nanocrystalline phosphors for solid-state lighting

Abstract We reported the terbium (Tb 3+ )/samarium (Sm 3+ ) co-doped white-emitting CaYAlO 4 (CYA) nanocrystalline phosphors synthesized by a citrated-based sol–gel method. The closely-packed porous nanoparticles of CYA had a pure tetragonal crystalline structure. The Sm 3+ co-activated CYA:Tb 3+ phosphors exhibited the emission peaks in the blue ( 5 D 3 → 7 F J =5,4,3,2 ), green ( 5 D 4 → 7 F J =6,5 ) and orange-red ( 4 G 5/2 → 6 H J =5/2,7/2,9/2 ) regions under an excitation wavelength of 381 nm and the cathodoluminescence spectra also showed similar behaviors. The emitted color was controlled by selecting the excitation wavelength. The energy transfer probability was calculated to analyze the energy transfer efficiency from the Tb 3+ to Sm 3+ ions in the CYA host lattice.