Red emission enhancement from CaMoO4:Eu3+ by co-doping of Bi3+ for near UV/blue LED pumped white pcLEDs: Energy transfer studies near

CaMoO4:Eu3+ (3 at. %)/Bi3+ (x at, %) nanophosphors were synthesized hydrothermally. All the samples can be excited by 280, 320, 393, and 464 nm (blue) wavelengths for generation of red color emission. Enhancement in D-5(0) > F-7(2) (615 nm) emission (f-f transition) of Eu3+ is observed when Bi is incorporated in CaMoO4:Eu3+ This is due to the efficient energy transfer from Bi3+ to Eu3+ ions, Introduction of Bi3+ in the system does not lead to the change of emission wavelength of Eu3+. However, Bi3+ incorporation in the system induces a shift in Mo-O charge transfer band absorption from 295 to 270 nm, This may be due to the increase in electronegativity between Mo and O bond in the presence of Bi3+ leading to change in crystal field environment of Mo6+ in MoO42-, At the optimal concentration of Bi3+, an enhancement in emission by a factor of similar to 10 and 4.2 in the respective excitation at 393 (F-7(0) > L-5(6)) and 464 nm (F-7(0) > D-5(2)) is observed. The energy transfer efficiency from Bi3+ to Eu3+ increases from 75% to 96%. The energy transfer is observed to occur mainly via dipole-dipole interactions. Maximum quantum yield value of 55% is observed from annealed CaMoO4:Eu3+ (3 at, %) when sensitized with Bi 34 (15 at, %) tinder 464 nm excitation. From Commission International dc FEciairage chromaticity coordinates, the color (red) saturation is observed to he nearly 100%, Published by AIP Publishing.