用巯基乙酸作稳定剂制备CdSe纳米晶的光学性质

摘要

Cadmium selenide nanocrystals were synthesized with mercaptoacteic acid as stabilizer and different size of nanocrystals from 2nm to 3nm were obtained by size selective precipitation.The optical properties of CdSe nanoclusters were studied by optical absorption, photoluminescence (PL) and photoluminescence excitation(PLE) spectroscopies at room temperature. The UV-vis absorption spectroscopy shows sharp absorption spectra with clear excitonic features which indicating a narrow size distribution for our samples. Photoluminescence investigation shows that our samples have two luminescence bands, a sharp high energy hand with high intensity near the absorption edge attributed to radiative recombination of electron hole pairs after relaxation to lowest quantum dot level, and the other lower energy broad band is attributed to the trapping center at the matrix interface region. More than one band appeared in the photoluminescence excitation (PLE) spectra, assigned to S-S and P-P transition. The luminescence properties obtained for different excitation are also presented.%以巯基乙酸为稳定剂制备了CdSe纳米晶,通过尺寸选择沉淀得到2nm到3nm之间不同尺寸的纳米晶,利用室温光吸收,光致发光(PL)和光致发光激发(PLE)谱来研究了CdSe纳米团簇的光学性质.紫外-可见吸收谱给出了具有清晰激光特征的尖锐吸收边,这表明样品的尺寸分布很窄.光致发光研究表明,样品有两个发射带,一个具有较高能量位于吸收边,来自电子-空穴对从最低激发态能级弛豫后的辐射复合,另一个低能发射带归属于基质与纳米晶界面存在的俘获中心.PLE谱中有2个吸收带,分别是S-S和P-P跃迁.最后还给出了不同激发能量下的发光特性.