Photoluminescence Spectra Of CdS Research Articles

Synthesis and photoluminescence spectra of CdS and CdS/ZnO doped PVK nanocomposite films

Abstract Organic/inorganic hybrid materials consisting of quantum dots and conjugate polymers are important for the application in light emitting devices. In the present work, we have studied the effect of CdS and CdS/ZnO nanoparticle addition on the structure and fluorescence properties of spin coated PVK (poly(N-vinyl carbozole)) nanocomposite films. CdS nanoparticles were synthesized by simple co-precipitation technique and ZnO shell was grown on the CdS nanoparticles by simple wet chemical approach. The nanoparticles and the hybrid nanocomposites have been characterized by using XRD, SEM, FT-IR, optical absorption and fluorescence spectroscopic techniques. The absorption peak for pure PVK remains at 345.5 nm accompanied with minor hump ~480 nm resulting from the incorporation of nanoparticles. It has been observed that the addition of nanoparticles to the hybrid material results in the enhancement of fluorescence intensity at 410 nm to 450 nm spectral regions. These results are important for the development of new light emitting devices at low fabrication costs.

Mechano and photoluminescence spectra of cadmium sulphide and cadmium selenide doped phosphors

The present paper deals with the mechanoluminescence and photoluminescence spectra of CdS and CdSe doped phosphors. It is found that PL spectra are similar to ML spectra of the phosphors within the limit of experimental errors. The activator concentration for which the PL intensity attains an optimum value is 1×10−3 and the ML intensity attains an optimum value for 4×10−3 concentrations. The PL spectra of CdSe:Mn, CdS:Au, CdS:Mn, CdS:Ag, and CdS:Cu phosphor have peak centered at 765nm, 770nm, 765nm, 740nm and 760nm respectively at an activator concentration 4×10−3. It is found that for a given phosphor the critical activator concentration for which the PL intensity attains an optimum value is always greater than that for the ML intensity. The mechanism of PL excitation and concentration quenching are discussed for the Cu, Mn, Ag and Au doped phosphors of CdS and CdSe. It is conclude that the centers which are responsible for PL emission should also be responsible for the ML emission.

Photoluminescence properties of single Mn-doped CdS nanocrystals studied by scanning near-field optical microscopy

We have fabricated Mn-doped CdS (CdS:Mn) nanocrystals embedded in Al2O3 matrices by sequential ion implantation and studied their photoluminescence (PL) properties by a scanning near-field optical microscope (SNOM). In the PL spectra of CdS:Mn nanocrystals measured by the SNOM, several sharp PL lines and a broad PL band were observed. The sharp PL lines are related to bound excitons at shallow impurities in CdS nanocrystals. The Mn-related PL spectrum is very broad even in single nanocrystals at low temperatures, and both the peak energy and the spectral width of the PL band depend on the excitation laser intensity. The PL properties of single CdS:Mn nanocrystals are discussed.

Optical manifestation of stacking faults in CdS 1− xSe x crystals

A manifestation of crystal regions with stacking faults has been found for the first time in the low-temperature reflectance and photoluminescence spectra of CdS 1− x Se x crystals with various compositions. X-ray structure analysis has confirmed the existence of crystal regions with stacking faults in the samples.

Room-temperature photoluminescence in spray-pyrolyzed CdS

Very intense room-temperature photoluminescence has been observed near 1000 nm in CdS films prepared by spray pyrolysis. Since this material can be easily fabricated into p-n devices, this suggests the possibility of inexpensive electro-optical devices. Also, the photoluminescence spectra of CdS and amorphous Si:H are very similar.