Probing the structure, morphology and multifold blue absorption of a new   red-emitting nanophosphor for LEDs
  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. 
Savvi Mishra, Isha Bharti, N. Vijayan, R. K. Sharma, L. M. Kandpal, V.   Shanker, M. K. Dalai, R. Rajeswari, C. K. Jayasanka...
cond-mat.mes-hall cond-mat.mtrl-sci