The water soluble quantum dots (QDs) are synthesized by the phase transfer and silica coating reaction. The photoluminescence intensity of silica-coated QDs are mainly affected by the amount of phase transfer agent, SDS (sodium dodecyl sulfate), and the maximum value is obtained at the cmc (critical micell concentration) concentration of SDS in the phase transfer reaction. Based on fluorescence spectra and field emission transmission electron microscope (FETEM), the energy transfer rate by forster resonance energy transfer (FRET) is increasing with the thickness of the silica shell coated on CdSe/ZnS QDs.
The spherical mesoporous silica is synthesized and incorporated with CdSe/ZnS quantum dots(QDs) for preparing micro beads to detect toxic and bio-materials with high sensitivity. The spherical silica beads with the brunauer-emmett-telle(BET) average pore size of 15 nm were prepared with a ratio 1, 3, 5-trimethylbenzen, as a swelling agent, to the block-copolymer template surfactant of over 1 and under vigorous mixing condition. The surface of spherical mesoporous silica is modified using octadecylsilane for incorporating QDs. Based on photoluminescence(PL) spectra, the relative brightness of mesoporous silica beads incorporated with 10 nM of QDs is 79,000 times brighter than that of Rodamine 6 G.
In this paper, CdS thin films, which were widely used window layer of the CdTe and the Cu(In,Ga)Se2 thin film solar cell, were grown by chemical bath deposition, and effects of pH of reaction solution on the structural and optical properties were investigated. For pH<10.5, as the pH of reaction solution was higher, the deposition rate of CdS films was increased by improving ion-by-ion reaction in the substrate surface and the crystallinity of the films was improved. However, when the pH was higher than 10.5, the deposition rate was decreased because of smaller Cd2+ ion concentration in the reaction solution. Also, the crystallinity of the films were deteriorated. The CdS films deposited at lower pH showed poor optical transmittance due to adsorbed colloidal particles, while the transmittance was improved for higher pH.
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Influence of CdS Post-deposition Treatment on CIGS Solar Cells Soo-Min Kwon, SangMok Kim, Chan-Wook Jeon New & Renewable Energy.2016; 12(1): 26. CrossRef
CdSe films were deposited on glass substrates (CdSe/glass) by thermal evaporation. Substrate temperature was lowered by cooling substrate holder with liquid nitrogen. Substrate temperatures were 200℃, 0℃ and -40℃. The crystallographic properties and surface morphologies of the CdSe/glass films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical and electrical properties of the films were investigated by dependence of energy gap, photosensitivity and resistivity on the substrate temperature. CdSe/glass showed energy gap of ～1.72 eV regardless of substrate temperature. The resistivity of the films decreased to 0.5 Ωcm by lowering the substrate temperature to -40℃. The CdSe/glass films prepared at 0℃ showed the highest photosensitivity among the films in this study.
Effect of Pre/Post-Treatment on the Performance of Cu(In,Ga)(S,Se)2 Absorber Layer Manufactured in a Two-Step Process A-Hyun Kim, GyeongA Lee, Chan-Wook Jeon New & Renewable Energy.2021; 17(4): 36. CrossRef
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