Synthesis, Assembly And Performance Of Semiconductor Hollow Spheres

Recently, preparation of nanomaterials with special structures has attract considerable attentions, among which hollow-structured materials are one of the most studied due to their special properties such as low density, high surface area and high permeability. Inorganic hollow spheres with special optical, optoelectronic, magnetic, electrical, thermal, electrochemical, photoelectrochemical, mechanical, and catalytic properties, have a wide range of potential applications. In this paper, SrTiO3 (strontium titanate, perovskite semiconductor) hollow spheres and TiO2-SrTiO3 heterostructured hollow spheres were synthesized through a polymer-template-assisted approach. The factors in controlling morphology and structure of hollow spheres were discussed in detail. The photoelectrical performance and catalytic property were also studied respectively.(1) Monodisperse SrTiO3 hollow spheres with open holes were prepared through a template-assisted approach. PSA colloidal spheres prepared by emulation polymerization of styrene and acrylic acid were used as templates. Tetra-n-butyl titanate (TBT) and strontium chloride hexahydrate (SCH) were employed as the supply of Ti and Sr respectively. Furthermore, these SrTiO3 hollow spheres self-assembled directly into densely-packed film at a "hexane-water" interface. TEM, SEM, HRTEM, XRD, etc. were employed to characterize the morphology and structure of the SrTiO3 hollow spheres, as well as the corresponding nanofilms. The effects of the Sr/Ti atomic ratios in reagents on morphology, content of the as-obtained hollow spheres and the photoelectrical performance of the nanofilms were investigated. Finally, a UV photodetector was successfully constructed from the as-obtained SrTiO3 hollow-sphere film.(2) Monodisperse TiO2 hollow spheres with open holes were prepared through a template-assisted approach. PSA colloidal spheres prepared by emulation polymerization of styrene and acrylic acid were used as templates. TBT were employed as the supply of Ti. Followed by the hydrothermal treatment with Sr supply, TiO2-SrTiO3 heterostructured hollow spheres, whose spherical structures were well maintained, were obtained. TEM, SEM, HRTEM, XRD, XPS, etc. were employed to characterize the morphology and content of these TiO2-SrTiO3 heterostructured hollow spheres. The effects of the Sr/Ti atomic ratios on morphology, content, energy band and catalytic property of the as-obtained hollow spheres were investigated. There was optimum amount of SrTiO3 in the TiO2-SrTiO3 heterostructured hollow spheres when the molar ratio between SrTiO3 and TiO2 was 0.08:1. The photocatalytic rate constant of TiO2-SrTiO3 heterostructure hollow spheres was about 1.5 times higher than that of the TiO2 hollow spheres.