单分散性CdSe纳米晶的合成——成核及其生长过程

 在氩气保护下，用三辛基亚磷酸和油酸分别作为Se和Cd的配位体，在260～300 ℃的十八烯溶液中合成了尺寸可控的CdSe纳米晶。该纳米晶不用进行进一步的提纯和尺寸分离就具有单分散性，其量子尺寸限域效应非常明显——吸收光谱的第一吸收峰峰位随着纳米晶的长大而发生红移；该纳米晶质量很高，具有很强的发光能力，其发射光谱对称的形状和合理的Stokes频移（13 nm）显示，该纳米晶的发光完全出自带隙，没有来自缺陷的发光。此外，实验结果表明，通过改变三辛基亚磷酸的浓度可以调节成核和生长的快慢，从而可以在不同的反应时间得到不同尺寸的单分散性CdSe纳米晶。

Synthesis of Monodisperse CdSe Nanocrystals: Nucleation and Growth

With trioctylphosphine and oleic acid as the ligands of Se and Cd, high-quality CdSe nanocrystals with controlled particle size were synthesized in a 260～300 ℃ noncoordinating solvent octadecene under argon flow. The as-synthesized nanocrystals are monodisperse without any size-selective treatment, and exhibit the clear quantum confinement effect, which makes the first excitonic absorption peak shift to red with increasing particle size. The shape of the emission peak and the reasonable Stokes shift (13 nm) indicate that these nanocrystals have intense band-gap emission, devoid of significant trap-state emission. In addition, experimental results show that the rate of nucleation and subsequent growth can be easily tuned by altering the concentration of trioctylphosphine, by which monodisperse CdSe nanocrystals can be also obtained.