Novel KGd1−(x+y)EuxBiy (W1−zMozO4)2 nanocrystalline red phosphors for tricolor white LEDs

Abstract

Nanocrystalline KGd1−(x+y)EuxBiy(W1−zMozO4)2 was successfully synthesised via polymeric metal complex sol–gel synthesis method and the effect of Bi3+ and Mo incorporation in Eu3+:KGd(WO4)2 (KEGW) for red luminescence was discussed. TEM analysis confirms the nano dimension of KGW powder calcined at 650°C. Raman spectral results demonstrate that all Eu3+ doped and Bi3+ co-doped samples did not show structural changes and Mo doped samples show structural changes from monoclinic to anorthic structure at high doping concentrations. Excitation and emission results demonstrate that 50% Eu3+:KGW shows high intensity red emission without substantial quenching. Further increment in the intensity was observed with Bi3+ co-doping in the Eu3+:KGW matrix. Mo incorporation in the Bi3+, Eu3+:KGW matrix shows broad CT band with high intensity and narrow red emission.