| In recent years, semiconductor quantum dots have been nintensively investigated due to the quantum size efect and the surface efect. Because of the simple growth method, monodisperse nano crystals, evident quantumsize efect, good light-emiting property and strong optical nonlinear etc,â…¡-â…¥colloidal quantum dots prepared by colloidal chemistry technique show wide potential application prospect in light-emiting devices, single-electron devices and nonlinear optical devices.The search contents are divided into two parts.In the first part, the optical characteristics of nanocrystal, including the preparation, characterization, absorbance and fluorescence property, were studied.The influence of the size on it's fluorescence characteristics was discussed. The second part studies the effect of surface modification on CdSe QDs,including surface modification and the modified QDs samples'PL and time-resolved PL spectra character. The possible fluorescing mechanism is proposed also.Several CdSe nanocrystals with different sizes were obtained by the colloidal method in this paper. They exhibited fluorescence with different colors and high intensity. The PL spectra are symmetrical, and their full-width at half-maximum (FWHM)is small. The synthesized CdSe nanocrystals not only have a good monodisperse size distribution, but also exhibit steady high-quality optical properties.CdSe QDs samples with the same size were surface modified by injecting with 2-mercaptoethanol solution, and these modified samples have the same full width at half maximum(FWHM)and the same wavelength of PL peak,but the intensity of these PL changed regularly, as well as the fitted parameters of the time-resolved PL spectra.The possible fluorescing mechanism was proposed by discussing the influence of the surface modification on the optical characters of QDs. |
