Bhaskar Kumar Grandhe

SINGLE-PHASED AND EMISSION-TUNABLE CaLa2-xEuxZnO5 PHOSPHORS WITH BLUE LIGHT EXCITATION FOR WLEDS

Single-phased and emission-tunable CaLa2-xEuxZnO5 phosphors were synthesized by citric sol-gel method. Precisely adjusting the activator concentration in CaLa2ZnO5 (CLZ) phosphor, we could obtain blue-green (BG) to orange-red (OR) emissions from the 5D2, 1, 0 → 7FJ levels of Eu3+ with the blue excitation wavelength of 468 nm, which perfectly matches with the emission of blue LED chip. This fascinating result has provoked us to blend the green and red color tunable single phased phosphors with and without YAG:Ce to fabricate blue LED based white light emitting diodes (LED). The emission features thus interpreted are appropriately explained through their chromaticity coordinates and energy level diagram. Besides, its thermal stability is also investigated.

Synthesis and characterization of Eu3+ doped Gd2O3 nanotubes using multi wall carbon nanotubes as removable templates

Eu3+ doped Gd2O3 nanotubes have been synthesized using multi wall carbon nanotubes as removable templates by employing a liquid phase deposition method. The prepared Eu3+ doped Gd2O3 nanotubes were characterized by means of x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy, fourier transform infrared sepctroscopy and thermogravimetry and differential thermal analysis. XRD patterns conrm the cubic phase of Eu3+ doped Gd2O3 nanotubes. From the measured SEM images, the average diameter of the Eu3+: Gd2O3 nanotubes were estimated to be in the range of 50–70 nm. The photoluminescence analysis revealed that the Eu3+: Gd2O3 nanotubes can display a strong red emission peak at around 616 nm, due to the 5D0→7F2 electric dipole transition of Eu3+ ions. Such luminescent powders are expected to find potential applications in fluorescent lamps and display device applications.