纳米PbS/SiO_2气凝胶介孔组装体的制备及光学特性

Preparation and Optical Properties of Nano-PhS/SiO_2 Aerogel Assemblies

对用自行研制的ＳＣＤ－Ｉ型高压釜制备的ＳｉＯ２气凝胶与用胶体化学方法制备的ＰｂＳ纳米粒子的组装体系的光学性质进行了研究．用透射电镜观察了其形貌，用光吸收谱仪及荧光光谱仪测定其光吸收谱及荧光谱．发现样品的光吸收边随退火温度升高由可见逐渐移到红外波段．样品的光致发光强度随退火温度上升先增强直至５７３Ｋ，而后随退火温度上升而减弱．我们认为光吸收边红移是由量子限域效应引起的，而荧光强度变化与ＰｂＳ表面缺陷及激子的复合几率变化有关．

The studies were focused on the optical properties of supercritical-drying-technique- prepared silica aerogels assembled with PhS colloids synthesized by colloidal chemistry route. Transmission electron microscope was used to image the assembled samples. Fluorescence spectroscopy and absorption spectrophotometer were employed to investigate the optical properties of the assembled systems. Large optical absorption edges red-shift along with the increase of annealing temperature was observed, which can be attributed to the quantum confinement effects. Photoluminescence intensity enhances along with the increase of the annealing temperature to the maximum at 573K, dropping thereafter, and the photoluminescence peaks show small red-shifts in the meanwhile. These phenomena are related to quantum confinement effects, defect states in the particle surface and excitonic recombination probability.