不同环境因子作用下水溶性CdTe量子点的生长动力学研究

以硫普罗宁为稳定剂,水热法制备了水溶性CdTe量子点,系统研究了回流时间、反应物配比、pH值、反应温度和电解质种类等环境因子对量子点生长动力学及光物理性质的影响。结果表明,溶液的pH值及反应物配比对CdTe量子点的光物理性质均有重要影响。优化条件后,回流5 h可得到发射峰位于550 nm的CdTe量子点,其荧光量子效率高达52%;在氯化钠作用下,量子点生长加快,即高浓度氯化钠会减弱溶液中粒子间静电排斥,促进离子扩散,有利于量子点的生长;添加苯磺酸钠会抑制量子点的生长,有利于制备高荧光量子效率的小尺寸CdTe量子点。

Effects of Different Environmental Parameters on the Growth Kinetics of Aqueous CdTe Quantum Dots

We have synthesized highly photoluminescent and size-tunable CdTe quantum dots (QDs) in aqueous solution by using tiopronin (TP) as stabilizer. The effects of different environmental parameters, including the refluxing time, the molar ratio of reactants, the pH value, temperature and category of added electrolytes, on the growth kinetics and photophysical properties of CdTe QDs were investigated. The experimental results show that the pH value and the molar ratio of reactants have pronounced impacts on the as-prepared CdTe QDs. When the mixture is refluxed at pH=10 for 5 h, the CdTe QDs with emission peak at 550nm can be obtained and their photoluminescent quantum yields (PLQY) can be up to 52%. A high concentration of NaCl greatly weakens the interparticle electrostatic repulsion, hence favors monomer diffusion and then results in a faster growth of CdTe QDs; Sodium benzenesulfonate inhibits the growth rate of CdTe QDs, and the presence of sodium benzenesulfonate is helpful for the preparation of highly photoluminescent CdTe QDs with small size.