The Research On Synthesis And Application Of Metal Chalcogenides Nanomaterials

Metal chalcogenide nanomaterials has become a hotspot owe to its special structure features and outstanding optic, electrical, thermodynamic etc. physicochemical properties, and it attracts extensive attention in many fields such as electronic device, energy sources and biomedicine. The article focuses on the A2B3-type metal chalcogenide, prepares the S-doped Bi2Se3 microspheres with a hierarchical structure and ultrasmall Bi2Se3 nanodots, and studies the application of Bi2Se3 microspheres in Li-ion battery for energy storage, and the applications of ultrasmall Bi2Se3 nanodots in multimodal imaging and tumor therapy for biomedicine. The main conclusions are as follows:(1) S-doped Bi2Se3 hierarchical microstructure was successfully prepared from stable bismuth trichloride and selenium powder in the presence of mercaptoethanol by a solvothermal method. Compared with other syntheses, our preparation is characterized with the fast dissolving of Se powder in the presence of mercaptoethanol, and the low solvothermal temperature. More importantly, the resultant hierarchical microstructure is made up of very thin nanosheets (-1 nm), which are stacked with a space of about 0.7 nm from each other. Such unique structure provides large space for intercalation and de-intercalation of lithium ions, leading to an initial capacity of discharge capacity of 771.3 mAh g-1. Our research provides rational synthesis of layered semiconducting A2B3 (A= Sb, Bi; B= S, Se, Te) nanostructures for potential application in energy conversion and storage.(2) Ultrasmall Bi2Se3 nanodots was synthesized through a sample facile chemical method under ambient condition. Dissolving the selenium powder with the mixture of mercaptoethanol and ethanediamine at room temperature, and the product reacts with the Bi3+ions with the absence of bovine serum albumin (BSA) under stirring, and then excel hydrosoluble Bi2Se3 nanodots was harvested. The product was a monodisperse particles with a sub-3 nm size, and it takes a good stability in different mediums. Little biology toxicity was proved by a standard MTT experiment. Fantastic photoacoustic and CT imaging performance indicate Bi2Se3 nanodots takes fundamental functions for biomedical imaging. BSA-Bi2Se3 nanodots was successfully applied for photoacoustic imaging against tumor in vivo for the animal, and the 99mTc-marked Bi2Se3 was also used in SPECT-CT multi-modal 3D imaging in vivo. Therefore, the ultrasmall Bi2Se3 nanodots takes a potential application prospects in multi-modal imaging to diagnose tumor in biomedicine.(3) We expend the application of Bi2Se3 nanodots in tumor therapy based on the previous chapter study. As semiconductor materials, the bismuth selenide nanodots take a good photo-thermal conversion effect for the NIR light, and possess a attenuation for X-ray for the large atomic number of Bi element. So, it could act as NIR light absorber and radiosensitizing agent, applied in photothermal therapy, radiotherapy and their combination therapy. As-prepared Bi2Se3 nanodots take a high photo-thermal conversion efficiency (50.7%), and tumor-ablating therapeutic effect was gained in PTT and PTT-RT combination therapy against tumor of animal. The results indicate that the bismuth selenide nanomaterials have potential application prospect in photothermal therapy, radiotherapy and combination therapy against tumor.