There has been a stringent demand for blue (~450 to 470 nm) absorbing and red (~611 nm) emitting material systems in phosphor converted white light emitting diodes (WLEDs) available in the market. The conventionally used red-emitting Y2O3:Eu~(3+) phosphor has negligible absorption for blue light produced by GalnN based LED chips. To address this issue, a new red-emitting Gd2CaZnO5:Eu~(3+) (GCZO:Eu~(3+)) nanophosphor system having exceptionally strong absorption for blue (~465 nm) and significant red (~611 nm) photoluminescence is presented. This is attributed to a dominant f-f transition (~5D0 → ~7F2) of Eu~(3+) ions, arising due to an efficient energy transfer from the Gd~(3+) sites of the host lattice to Eu~(3+) ions. The external quantum yield (QY) measured at 465 nm absorption and 611 nm emission revealed that the GCZO:Eu~(3+) nanophosphor has better QY of 23% as compared to commercial Y2O3:Eu~(3+), which is <1%. X-ray diffraction and microscopy observations showed the nanocrystalline nature and slightly elongated morphology of the sample, respectively. While the energy dispersive X-ray analysis identified the chemical constituents of the GCZO:Eu~(3+) nanophosphor, the color overlay imaging confirmed the substitution of Eu~(3+) for Gd~(3+) ions. As seen from the QY statistics it is highly anticipated that the multifold absorption at ~465 nm would certainly improve the color rendering properties of existing WLEDs.
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