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Thin films of SrAl2O4:Eu2+,Dy3+ phosphor were deposited on silicon [Si (100)] substrates using a 248 nm KrF pulsed laser. Deposition parameters, such as substrate temperature, pulse repetition rate, number of laser pulses, and base pressure, were varied during the film deposition process. Based on the x-ray diffraction data, all the films were amorphous but were emitting visible light when excited by a monochromatic xenon lamp. The chemical composition and the stoichiometry of the films determined by the Rutherford backscattering spectroscopy were consistent with the commercial SrAl2O4:Eu2+,Dy3+ powder used to prepare the films. Photoluminescence (PL) emission spectra of the films were characterized by major green emission with a maximum at ∼520 nm and minor red emission with a maximum at 630 nm. The green and red photoluminescence at 520 and 630 nm are associated with the 4f65d→4f7(S87/2) and D50-F72 transitions of Eu2+ and residual Eu3+ ions, respectively. Brighter films were shown to have relatively hi...

PbS and ZnO nanoparticles prepared separately by a sol-gel process were incorporated in SiO2 by an ex situ method, resulting in a green emitting ZnO–SiO2:PbS powder phosphor. Particle morphology, structure, and chemical composition of the ZnO nanoparticles, PbS nanoparticles, and ZnO–SiO2:PbS composite were analyzed with transmission electron microscopy, x-ray diffraction, and energy dispersive spectroscopy (EDS), respectively. With or without ZnO nanoparticles, green photoluminescence with a peak at 540nm was observed from SiO2:PbS when excited with a 325nm He–Cd laser in air at room temperature. This peak was different from defect-related emission from ZnO nanoparticles at 580nm and red-orange emission from SiO2:Pb2+ with a broad peak at 600–750nm. Again, the 540nm peak was different from the band edge emission from pure PbS nanoparticles at 1200nm. Note that this emission (540nm) was enhanced considerably when ZnO nanoparticles were incorporated. Photoluminescence properties of ZnO–SiO2:PbS is discussed.

Ce3+–Tb3+ co-activated ZnAl2O4 powder phosphors were prepared by a solution combustion method using urea as a fuel. X-ray diffraction characterization showed that all the powders crystallized in the well known cubic spinel phase of ZnAl2O4. An enhanced down-converted green emission associated with the 5D4→7F5 transitions of Tb3+ ions was observed at 543 nm from the ZnAl2O4:Ce3+, Tb3+ powders with different concentrations of Ce3+ and Tb3+. It was inferred from the fluorescence decay data that the enhancement was due to energy transfer from Ce3+ to Tb3+. Further, cathodoluminescence intensity degradation of the ZnAl2O4:Ce3+, Tb3+ powder phosphors was investigated when the powders were irradiated with 2 keV electrons. X-ray photoelectron spectroscopy was used to analyze the chemical and electronic states of individual elements before and after electron irradiation. The ZnAl2O4:Ce3+, Tb3+ phosphor was evaluated to be used as a UV down-converting layer in conventional silicon photovoltaic cells or as a source ...