UV Light Induced Growth Of Silver Nanoparticals

Semiconductor quantum dots (QDs) are an important optical-electrical material. Quantum dots show a variety of new interesting properties that are completely different from bulk materials, such as quantum size-dependent effects, Coulomb blockade effects and dielectric confined effects. Meanwhile, transparency matrix consisting of small metal particles can produce strong surface plasma resonance (SPR) and have a large third-order nonlinear coefficient near the SPR absorption frequency, which have a widely application in optics, materials science and so on.In this work, we prepare CdS, CdS/Ag particles in phosphate glasses. The research of this work and the main conclusion is described in brief as follows.1. We use the glass precipitation of the oversaturation CdS solid solution then annealing under the certain condition to produce the CdS QDs. The performance of CdS QDs are characteristic by X -ray diffraction(XRD), high resolution scanning electron microscope (HRSEM), absorption spectra and fluorescence spectra. We found that the higher concentration CdS QDs doped in phosphate glasses can prepared by glass precipitation. The particles were distributed in glass substrate uniform and size nearly equation. Both absorption spectra and fluorescence spectra exhibit red-shift, which is the effect of quantum size. The fluorescence spectra exhibit well-defined peaks associated with band-edge luminescence and recombination at defects. We can increase the thermal treatment temperature to improve the crystalline integrity and reduce the luminescence intensity by defects. The relation between QDs size and preparation time is nearly t^1/2.2. CdS-P₂O₅-Na₂S system glass doped with CdS/Ag particles were prepared by a glass precipitation method and thermal treatment after UV bean irradiation. The results indicated that the electron on the semiconductor surface can induce silver ions upon the irradiation of the glass and lead to formation of silver particles. Because there was energy transfer between CdS and Ag, the luminescence of the samples was vanished. We can obtain CdS_Core-Ag_shell and Ag_Core-CdS_shell particles by control the melting time.3. We use orthogonal experimental design and ion exchange method to prepare...