Green Emitting Cerium Doped CaS Whiskers Grown by Solid State Diffusion Method

Abstract

Undoped and cerium doped Calcium sulfide (CaS) phosphors were synthesized using solid state diffusion method. The X-ray diffraction pattern revealed that both undoped and doped CaS crystallites have cubic structure with average crystallite size varying from 20 to 30 nm. Scanning electron micrographs indicated that Ce doped CaS phosphors were composed of whiskers with different dimensions and orientations. The optical properties of undoped and Ce doped particles were characterized using Photoluminescence (PL) and UV-Vis absorption spectroscopy. The PL emission spectrum of cerium doped CaS phosphors for an excitation wavelength 465 nm showed a main peak at 500 nm and a shoulder peak at 556 nm due to 5d → 4f transition in Ce ions. The variation of PL intensity with cerium concentration was investigated and the maximum PL intensity was obtained for a doping concentration of 3 wt.%. The optical band gap of the samples was estimated from the diffuse reflectance spectrum and was found to increase with increase in cerium concentration. The enhanced optical properties of these phosphors can be exploited in various optoelectronic devices including displays and bioimaging techniques.

Development of rare earth doped CaS phosphors for radiation detection

“…The powders were mixed in a molar ratio of CaS:EuCl 3 •6H 2 O or CeCl 3 = 0.97:0.03, 0.995:0.005, and 0.999:0.001. For CaS:Ce, NH 4 Cl powder was added as the reducing agent 20), 21) by the weight ratio of CaS:Ce to NH 4 Cl of 0.5:0.02. The mixtures were pressured at 10 tons for 10 min and pelletized.…”

EFFECT OF Ce DOPING ON THE CHARACTERISTIC PROPERTIES OF CdS NANOPARTICLES

“…However, contrary to these studies, it is emphasized that cerium ions doped semiconductor materials have lower particle size and higher surface area (20). Ce doped CaS (21,22) and Ce doped SrS (23,24) nanoparticles were synthesized using different synthetic techniques such as solid state diffusion and chemical co-precipitation, and data on their characteristic properties (structural, morphological and optical) were reported. To date, no experimental studies have been conducted on the investigation of the photovoltaic properties of Ce doped CdS nanoparticles.…”