Thakur Priya, Joshi Satyawati S, Kapoor Sudhir, Mukherjee Tulsi
Department of Chemistry, University of Pune, Pune-411007, India.
Langmuir. 2009 Jun 2;25(11):6334-40. doi: 10.1021/la900437x.
Biomodified CdS nanoparticles were synthesized using l-cysteine as a capping agent in the colloidal state as a function of pH. The role of pH on the size and structure of CdS nanoparticles was investigated in detail. At pH 7.4 and 9.1, X-ray diffraction spectra of as prepared samples showed the presence of a mixture of cubic and hexagonal phases while cubic phase was formed at pH 11.2. A gradual transition to the hexagonal phase was observed for refluxed samples at pH 9.1 and 11.2. Whereas, at pH 7.4, the sample remains in a mixture of cubic and hexagonal phase even after refluxing. The particle size of as prepared samples was about 2 nm, and for refluxed samples the size increased up to 10 nm. The binding of cadmium through thiol group is evidenced by infrared spectra. An intense band due to C-C-N vibration was observed after 24 h of reflux. The formation of a specific molecular cluster determines the growth of a particular phase. Transmission electron microscopy (TEM) studies support the X-ray diffraction (XRD) studies and exhibit well separated spherical particles while refluxed samples show clustering.
以l-半胱氨酸作为封端剂，在胶体状态下合成了生物改性的硫化镉纳米颗粒，其为pH的函数。详细研究了pH对硫化镉纳米颗粒尺寸和结构的影响。在pH 7.4和9.1时，所制备样品的X射线衍射光谱显示存在立方相和六方相的混合物，而在pH 11.2时形成立方相。在pH 9.1和11.2下，观察到回流样品向六方相的逐渐转变。然而，在pH 7.4时，即使回流后样品仍保持立方相和六方相的混合物。所制备样品的粒径约为2 nm，对于回流样品，粒径增加至10 nm。红外光谱证明了镉通过硫醇基团的结合。回流24小时后观察到由于C-C-N振动产生的强吸收带。特定分子簇的形成决定了特定相的生长。透射电子显微镜（TEM）研究支持X射线衍射（XRD）研究，并显示出分离良好的球形颗粒，而回流样品则显示出聚集。
