pH-Controlled Hydrothermal Synthesis of Submicrometer-Sized CdS Spheres with Uniform Size Distribution

For several decades, intensive research has been carried out on the morphological control of semiconductor nanomaterials. This is because semiconductor materials have various unique properties, which can be attributed to their shape and size.1-3 In particular, many researchers have carried out in-depth studies on CdS because it has numerous applications; for example, CdS can be used as a photocatalyst4 as well as in solar cells5 and light-emitting diodes.6 CdS has been synthesized by solid-state methods,7,8 solvothermal methods,9,10 precipitation,11 micro-wave-assisted solvothermal method,12 and liquid-crystal tem-plating,13 and calcinations of Cd-thiolates.14 Among these, solvo-thermal methods involving the use of Cd(II) ions as the metal source, various sulfur-containing ligands as sulfur sources, and shape-directing agents have been studied extensively. L-Cysteine has been employed as the sulfur source in many solvotherma