Marandi M, Taghavinia N, Iraji Zad A, Mahdavi S M
Nanotechnology. 2005 Feb;16(2):334-8. doi: 10.1088/0957-4484/16/2/027. Epub 2005 Jan 25.
The optical and electrical properties of semiconductor nanoparticles are strongly dependent on their size. A flexible control of the size of the nanoparticles is of interest for tuning their properties for different applications. Here we use a coupled method to control the size of CdS nanoparticles. The method involves the photochemical growth of CdS nanoparticles together with the use of a capping agent as an inhibiting factor. CdS nanoparticles were formed through a photoinduced reaction of CdSO(4) and Na(2)S(2)O(3) in an aqueous solution. Mercaptoethanol (C(2)H(6)OS) was used as the capping agent, and we investigated the effect of illumination time, illumination intensity and the concentration of capping agent on the nanoparticle size. Transmission electron microscopy (TEM) shows crystalline nanoparticles with relatively low dispersion. Optical absorption spectroscopy was mainly used to measure the band gap and size of the nanoparticles. Increasing the illumination time or illumination intensity increases the nanoparticle size, while higher capping agent concentration leads to smaller nanoparticle size. A band gap range of 2.75-3.4 eV was possible with our experimental conditions, corresponding to a 3.2-6.0 nm size range.
半导体纳米颗粒的光学和电学性质强烈依赖于其尺寸。灵活控制纳米颗粒的尺寸对于针对不同应用调整其性质具有重要意义。在此，我们使用一种耦合方法来控制硫化镉（CdS）纳米颗粒的尺寸。该方法涉及CdS纳米颗粒的光化学生长以及使用封端剂作为抑制因子。CdS纳米颗粒是通过硫酸镉（CdSO₄）和硫代硫酸钠（Na₂S₂O₃）在水溶液中的光诱导反应形成的。巯基乙醇（C₂H₆OS）用作封端剂，并且我们研究了光照时间、光照强度和封端剂浓度对纳米颗粒尺寸的影响。透射电子显微镜（TEM）显示出具有相对低分散性的结晶纳米颗粒。光吸收光谱主要用于测量纳米颗粒的带隙和尺寸。增加光照时间或光照强度会增大纳米颗粒尺寸，而更高的封端剂浓度会导致更小的纳米颗粒尺寸。在我们的实验条件下，带隙范围为2.75 - 3.4电子伏特是可能的，对应于3.2 - 6.0纳米的尺寸范围。
