静电自组装制备CdTe量子点纳米薄膜

以巯基丙酸为稳定剂, 在水相中合成了表面带负电荷、具有良好的分散性、平均粒径为5nm的CdTe量子点. 通过CdTe量子点与阳离子聚电解质聚二烯丙基二甲基氯化铵(PDDA)和阴离子聚电解质聚苯乙烯磺酸钠(PSS)之间的静电相互作用, 在石英基片表面通过层层静电自组装方法制备了多层CdTe量子点纳米薄膜. 以荧光分光光度计、UV-Vis、XPS、AFM等测试手段对所得的CdTe量子点纳米薄膜进行了表征. 研究结果表明, CdTe量子点自组装多层薄膜的UV-Vis吸光度与组装层数基本呈线性关系, 薄膜成膜质量良好. 自组装薄膜基本上规整并均匀地覆盖在石英基底表面, 但薄膜中存在部分CdTe量子点聚集现象. 通过在相邻的两层CdTe量子点之间引入基本结构单元为PDDA/PSS/PDDA的聚电解质复合层, 可有效提高CdTe量子点纳米薄膜的成膜质量. 所得的CdTe量子点纳米薄膜具有良好的荧光光致发光性.

Fabrication of Ultrathin Films of CdTe Quantum Dots by Electrostatic Self-assembly Method

Negatively charged and monodisperse CdTe quantum dots (QDs) with average size of about 5nm were synthesized in aqueous solution using 3-mercaptopropionic acid as stabilizing reagent. Through the electrostatic interactions among the negative surface charges on CdTe QDs, the cationic groups of poly(diallyldimethylammonium chloride) (PDDA) and the anionic groups of poly(sodium 4-styrene-sulfonate) (PSS), ultrathin multilayer of CdTe QDs were fabricated on the pretreated quartz substrate by layer-by-layer electrostatic self-assembly method. UV-Vis spectra, photoluminescence spectra, XPS and AFM were used to characterize the ultrathin films. The results show that there is a linear relationship between the adsorption and the layer numbers of the thin films, indicating that the resultant nanofilms have good quality. The ultrathin films are flatly deposited on the quartz surface with some aggregates of CdTe QDs on it. The stability and quality of the films can be improved by the introduction of polyelectrolyte multilayers of PDDA/PSS/PDDA between two adjacent layers of CdTe QDs on the substrate. The prepared ultrathin films of CdTe QDs show good photoluminescence property.