A promising novel orange-red emitting SrZnV2O7:Sm3+ nanophosphor for phosphor-converted white LEDs with near-ultraviolet excitation

A novel trivalent samarium doped SrZnV2O7 nanophosphors was developed via urea assisted solution combustion method using metal nitrates as initial raw materials. The qualitative and quantitative phase analysis was carried out using Rietveld refinement technique. It was found to crystallize in monoclinic lattice with the P12(1)/n1 (14) space group. The photoluminescent spectral study of SrZnV2O7:Sm3+ revealed that the excitation of 405 nm yields the characteristic emission peaks at 569, 599, 640 and 702 nm due to (4)G(5/2) -> H-6(5/2), (4)G(5/2) -> H-6(7/2), (4)G(5/2) -> H-6(9/2) and (4)G(5/2) -> H-6(11/2) respectively. The optimum concentration of Sm3+ ion in SrZnV2O7 for best luminescence was found to be 2 mol%. The luminescence intensity was further enhanced by incorporating compensator charge R+ (R=Li, Na, and K) into the SrZnV2O7:0.02Sm(3+) nanophosphor. The critical distance for non-radiative energy transfer was calculated to be 26.64 angstrom. Dipole-dipole (d-d) interactions were ascribed as the major factor responsible for concentration quenching arising from the over-doping of the.activator ions. The results indicate that these nanophosphors are suitable candidate for PC-WLEDs using near UV excitation. (C) 2015 Elsevier Ltd. All rights reserved.