  There has been a stringent demand for blue (~450-470 nm) absorbing and red
(~611 nm) emitting material system in phosphor converted white light emitting
diodes (WLEDs) available in the market. Conventionally used red-emitting
Y2O3:Eu3+phosphor has negligible absorption for blue light produced by GaInN
based LED chip. To address this issue, a new red-emitting Gd2CaZnO5:Eu3+
(GCZO:Eu3+) nanophosphor system having exceptionally strong absorption for blue
(~465 nm) and significant red (~611 nm) photoluminescence (PL) is presented.
This is attributed to a dominant f-f transition (5D0\rightarrow7F2) of Eu3+
ions, aroused due to an efficient energy transfer from the Gd3+ sites of the
host lattice to Eu3+ ions. X-ray diffraction and microscopy observations
revealed the nanocrystalline nature and a bit elongated morphology of the
sample respectively. While the energy dispersive x-ray analysis identified the
chemical constituents of the GCZO:Eu3+ nanophosphor, the color overlay imaging
confirmed the substitution of Eu3+ for Gd3+ ions. It is highly anticipated that
the multifold absorption at ~465 nm would certainly improve the color rendering
properties of existing WLEDs.
