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Colloidal semiconductor nanocrystals exhibit physical properties that are characteristic of intermediate size scales between molecular states and solid state materials, and are often called quantum dots. Solid state semiconductor materials have been used extensively as scintillation detectors for ionizing radiation. We describe the use of semiconductor quantum dot - organic polymer composites for...
The main requirements for the MCT (CdxHg1-xTe) structures optimization for increase of the stimulated emission wavelength under optical pumping are discussed. The stimulated emission at wavelengths 2-2.5 μm at room temperature from optimized MCT structures is observed experimentally. The obtained experimental data are the first observation of stimulated emission from the MCT structures at these wavelengths...
We report integration of CdTe quantum dot (QD) film with LnCap (prostate cancer) cell and CdSe QD probes with cortical neurons for control of cellular activity. We demonstrate the remote switching of cellular activity by exciting QDs with light. Changes in membrane potential and ionic currents are recorded using the patch-clamp method. Upon excitation, the cell shows activation of ion channels and...
Preparation and characterization of CdSe thin film semiconductors, prepared by cathodic electrodeposition from an acid sulfate solution (CdSO4 - SeO2), were investigated. The effect of the bath temperature and how it affects the CdSe deposits was studied. The formation of compact barrier layers of zinc blende CdSe was attained. X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests present...
CdS polycrystalline thin films were fabricated by magnetron sputtering and the influence of substrates, sputtering powers, pressures, and substrate temperatures on the structure of thin films is investigated. The films deposited on substrates of glass, quartz, SnO2: F and p-type single silicon are hexagonal phase and they grow preferentially along (002) planes. As the radio-frequency power and substrate...
CdSe/ZnS colloidal quantum dot generally exists blinking phenomenon during luminescence process, that remarkably influences its application as a single photon source. In this work, we used the effect of surface plasmon to effectively suppressed the blinking by locating quantum dot on gold film. The anti-bunching character was also observed with g(2)(0) as low as 0.34 at room temperature. Surface plasmon...
We have made CdS/CdTe solar cells on polyimides from different sources. These cells were fabricated using sputtered zinc oxide doped with aluminum as the transparent conducting oxide. The CdS and CdTe were also deposited by sputtering. In this paper we report properties of the sputtered AZO and its changes with CdCl2 heat treatments. We have achieved a cell efficiency of 10.5% at air mass 1.5G illumination.
The CdSe nanoparticles have been synthesized by hot-injection method, and thermal annealing was used to improve the crystallinity of synthesized nanoparticles and reconstruct the surface of nanoparticles. The synthesized and annealed CdSe nanoparticles were characterized by TEM, XRD and PL spectra. After thermal annealing followed by a solvent exchange process, the CdSe nanoparticles were used to...
Two-junction tandem thin-film photovoltaic cells are composed of a wide-bandgap top cell overlying a narrower-bandgap bottom cell. CdTe, with a bandgap of 1.5 eV, can function effectively as a top cell when paired with a bottom cell of appropriate bandgap. Effective two-junction cells require a back contact to the top cell that is transparent to the sub-bandgap radiation absorbed by the bottom cell...
To widen the variety of substrate choice of Cu(In, Ga)Se2 (CIGS) solar cells, a lift off process was developed without an intentional sacrifice layer between CIGS and Mo back contact layers. CIGS films grown on Mo/glass substrates were transferred to alternative substrates of glass and polyimide. Based on the transferred CIGS films, deices with ITO/ZnO/CdS/CIGS/Mo/epoxy/alternative-substrates structure...
On this paper, we have studied the effect of the quality of different layers and their influence on the Voc of a standard CISEL?? cell. The objective is to asset the magnitude of the global losses and to identify the responsibility of each layer on this final value. For this, we have carried several simulations with the SCAPS2.7.03 software. We propose a model for the standard cell, and then we substitute...
We have studied magnetron sputtered CdS/CdTe cells having CdTe or CdS intentionally doped with either Si, P or Cu. This study was done to understand the effects of doping on the transient behavior and J-V performance of CdTe cells. Different chemical group elements were selected to see their comparative effects on cell response. In comparison with undoped CdTe, the cells with Si or P doping show enhanced...
The lifetime-limiting failure mechanisms of CuInGaSSe (CIGSS) solar devices made by Shell Solar Industries (SSI) were investigated. In our study, SSI minimodules were exposed to dry-heat 85??C, damp-heat 85??C/85% RH and aerobic and anaerobic room temperature and 85??C water baths. After 200 hours exposure to moisture-containing environments, the average device performance decreased by more than 30%...
Electrodeposition of zinc oxide layers has been carried out in simple aqueous solutions at 80??C in presence of zinc ions and dissolved oxygen. Extrinsic n type doping has been proven to be effective by anionic substitution of oxygen by chlorine, using chloride containing electrolytes. Doping level upper values up to 9.1019 cm-3 have been obtained, associated with lateral resistivies in the 2-5 10...
Cadmium telluride (CdTe) is a good absorber layer for solar cells with a predicted efficiency of 29% however the highest reported efficiency is only <17% due to various loss mechanisms. One particular loss is attributed to non-uniformity in grain shape and size by Karpov. Simulation of Karpov's model yields counter-intuitive insight that highlights how empirical data can lead researchers to wrong...
The effects of post annealing treatment were investigated on the CdS sensitized ZnO and TiO2 nanocrystalline solar cells. It was found that the annealing will increase the cell efficiency on ZnO and TiO2 with porous structures. A significant increase of cell efficiency from 0.54% to 1.07% was observed for CdS sensitized porous ZnO solar cells after annealing and 0.52% to 1.29% for CdS sensitized electrospun...
The formation of low resistance ohmic contacts on p-type CdTe is a major challenge for the superstrate solar cell the dominant device configuration for this technology. It is even a greater challenge for the substrate configuration, since the back contact material is deposited first and is therefore influenced by subsequent high temperature fabrication processing. In this paper, the structural and...
The results of fellow creature order in amorphous alloys from 0, 5 to 1, 0 at.% cadmium at temperatures 293, 323 K and liquidus temperature 613 K researches by method of X-ray analysis are presented in this work.
Nanocrystalline (NC) semiconductor materials have previously been studied as a means of increasing the exciton multiplicity upon the impingement of visible light, for applications such as solar cells. If the multi-exciton states have highly uniform multiplicities across macroscopic NC samples, then one can also potentially quench the statistical counting noise associated with charge-carrier creation...
CdSe QDs in sol-gel films are promising for nonlinear optical waveguide devices. We measured the two-photon absorption (TPA) coefficient at 820 nm in such films, and TPA-induced fluorescence over the 730-980 nm wavelength range.
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