Synthesis Monodisperse CdS Nanocrystals Templated In Nanotubes Of Serpentine

Nanometer (nm) scale structures represent an exciting, challenging and rapidly expanding area of research that crosses the borders between many disciplines of sciences and engineering.One-dimensional nanostructures, e.g. nanowires and nanotubes, are playing a special role within the realm of nanoscience and nanotechnology. With decrease in size of nanowires or nanotubes, singularities in the electronic density of states develop at special energies. The density of states becomes very large, appearing to be very different from that of crystalline solids or even two dimensional systems. Zero-dimensional materials, like quantum dots and semiconductor nanoclusters, have been showing distinct electronic structures from their bulk counterparts, and exhibited novel optical properties. One-dimensional materials, representatively serpentine nanotubes are expected to show novel properties.The discovery of serpentine nanotubes in the chrysotlie-serpophite rock was reported. Transmission electron microscope (TEM) images show that the nanotubes are multiwalled. Rarely nanotubes appear capped. Their lengths and inner diameters range from 100 to 1000 nm and 12 to 25 nm, respectively.CdS nanoparticles were synthesized by using an aqueous precipitation method; this method is simple, fast and can be developed at room temperature. The obtained particles were characterized using TEM and spectroscopic techniques. TEM images show well dispersed particles and The particle size was 15 nm. This particle size produce a quantum confinement observed in an increment on the band gap value. CdS nanocrystals show an emission band with a maximum in 531 nm.Nanosystem have been formed by the infiltration of CdS nanoparticles into nanotubes of serpentine. Photoluminescence of these templated nanowires was studied under the excitation of the light from a xenon lamp at 400nm wavelengths. Strong interactions of nanoparticles with structural defects of the template were observed. The efficiency of emission in a semiconductor can be improved by forming nanosystem due to the combined effect of the quantum and dielectric confinement. Semiconductor nanoparticles represent emitters with high quantum efficiency. Arranging them in nanotubes can lead to further emission improvement by exploiting the dielectric confinement factor.