不同环境因素对水热法合成碲化镉量子点的影响

Effects of Different Environmental Parameters on the Hydrothermal Preparation of Cadmium Telluride Quantum Dots

对比了不同巯基稳定剂和前体浓度对水热环境CdTe量子点的生长过程和光物理性质的影响。结果表明,巯基丙酸与镉前体的结合能力较强,一定程度上减小了前体溶液中镉的浓度,故CdTe量子点生长速率较慢;空间位阻较大的硫普罗宁与镉前体的结合相对较弱,因此导致CdTe量子点生长较快。巯基丙酸有利于制备发光波长较短的高荧光强度CdTe量子点,而硫普罗宁有利于制备发光波长较长的高荧光强度CdTe量子点。前体浓度对CdTe量子点的生长速率和光物理性质的影响不明显。在上述实验结果基础上,考察了水溶性乙酸钠和聚丙烯酸钠电解质对水热环境中CdTe量子点的生长过程和光物理性质的影响。结果表明,添加乙酸钠后可提高CdTe量子点的生长速率,进而导致CdTe量子点的表面重构和钝化能力下降,使荧光强度降低;聚丙烯酸钠对镉单体独特的固定作用导致CdTe量子点生长缓慢,尺寸集中化受限,钝化能力降低,使荧光强度下降更加明显。

Thiol-stablized cadmium telluride quantum dots（ CdTe QDs） were synthesized in aqueous solution. The effects of precursor concentrations and the types of thiol stabilizer were fully investigated and discussed. The variation in the growth rate of aqueous CdTe QDs was further studied to correlate the photophysical properties of the as-prepared CdTe QDs with the types of the added small molecule and macromolecule electrolytes. The experimental results reveal that the nature of the stabilizers and the additives of electrolyte influence significantly on the growth rate of CdTe QDs and hence the fluorescence intensity when compared with the precursor concentrations. The poly （ sodium acrylic acid） has a more pronounced deactivating effect on the growth-up of CdTe QDs when compared with sodium acetate, and the growth rate of CdTe QDs is mainly determined by the relative diffusion rate of the monomer