Bacterial Biosynthesis of Cadmium Sulfide Nanoparticles

Nanoparticles, also known as nanocrystallites or Q-particles, with typical diameters up to 10-20 nm,form a link between molecular and bulk states of matter. The optical, chemical and electronic properties of nanocrystals are dependent on physical properties, such as particle size distribution, shape, and crystallinity. Therefore, the challenge in semiconductor nanocrystal synthesis is to precisely control these properties by manipulating synthetic parameters.In recent years, semiconductor nanoparticle quantum dots have attracted considerable attention due totheir potential applications in biosensors, electronic and optical devices [1]. Among these materials, CdS, one of the most important IV–VI group semiconductors, is a potential candidate in fluorescent biological labels, photoelectric devices and photocatalysts [2,3,4]. A variety of chemical techniques are used for the synthesis of CdS nanoparticles , including hydrothermal synthesis [5], microemulsion method [6] and ultraviolet (UV) irradiation technology [7] and etc