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采用水溶性前驱物在乙醇介质中制备了不同[S2-]/[Pb2+]摩尔比例的PbS纳米晶,利用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见吸收光谱(Abs)、光致发光谱(PL)对所制备PbS纳米晶的晶体结构、纳米晶粒径、形貌以及能带结构和发光特性进行了表征,结果表明:随着前驱物[S2-]/[Pb2+]摩尔比例的提高,PbS纳米晶颗粒尺寸从3.9 nm增大到5.9 nm,发光峰值位置从1 009 nm移动到1 486 nm。通过拟合[S2-]/[Pb2+]=0.5条件下PbS纳米晶平均粒径对时间变化曲线,发现该方法下PbS纳米晶所经历的生长机制为Ostwald成熟化。运用经典纳米晶扩散控制生长模型,解释了实验中随着[S2-]/[Pb2+]的提高对溶液中纳米晶生长速率的影响。
The PbS nanocrystals with different molar ratios of [S2 -] / [Pb2 +] were prepared by ethanol precipitation using water - soluble precursors. The structure of PbS nanocrystals was characterized by XRD, TEM and Abs. The crystal structure, crystal size, morphology and energy band structure and luminescence properties of PbS nanocrystals were characterized by photoluminescence spectroscopy (PL). The results showed that with the increase of precursor [S2 -] / [Pb2 + ] Molar ratio increases, the particle size of PbS nanocrystals increases from 3.9 nm to 5.9 nm, and the emission peak position shifts from 1 009 nm to 1 486 nm. The results show that the growth mechanism of PbS nanocrystals under this method is Ostwald maturation by fitting the average particle size of PbS nanocrystals under the condition of [S2 -] / [Pb2 +] = 0.5. Using classical nanocrystalline diffusion controlled growth model, the effect of [S2 -] / [Pb2 +] on the growth rate of nanocrystals in solution was explained.