Controlled Synthesis And Photodetecting Properties Of Hexagonal Bi₁₉S₂₇I₃ One-Dimensional Nanostructures

Semiconductor nanomaterials, which are key building blocks for the next generation of optoelectronic devices such as light-emitting diodes, solar cells, photodetectors, field-effect transistors, thermoelectric devices and so on, have been extensively studied due to their anisotropic geometry, large surface-to-volume ratio and their superior exciton confinement in two dimensions compared to their bulk counterparts. Moreover, semiconductor nanomaterials have various mechanical properties and reactivities which depend on the crystallographic orientation.In this thesis, one-dimensional nanostructured Bi₁₉S₂₇I₃ have been controlled synthesized by the conventional solvothermal method. What's more, the photodetecting performances of the samples have also been investigated. The main studies are as follows:?1? Bi₁₉S₂₇I₃ one-dimensional nanostructures, including nanorod clusters film and nanorods powder, have been controllable prepared via solvothermal method. This research focuses on the formation of Bi₁₉S₂₇I₃ nanomaterial concerning the influences of reacting time, temperature and other factors, by which we can have a deeper understanding on the formation mechanism of Bi₁₉S₂₇I₃. Besides, the reaction conditions is under the temperature of 180 °C, the reaction time of 12 h and the solvent of ethylene glycol.?2? The preparation of Bi₁₉S₂₇I₃ nanomaterials was systematically characterized. X-ray powder diffraction patterns show that the high purity of the products is with hexagonal structure. The electron microscopy analyses reveal that the morphology of the film sample is apparently different from that of the powder sample. The former is composed of scattered and disordered nanorods, while the latter is composed of the nanorod clusters. The products show the light absorption performance are good in the range of visible and NIR light, and the bandgap is about 0.83 eV. Through the test of the photoelectric performance, the Bi₁₉S₂₇I₃ samples are highly sensitive to visible and near-infrared light irradiation. Especially, they exhibit the better photoelectric response under the near-infrared light irradiation. Besides, photoelectric performance can maintain stable photoresponse under the multiple loops, indicating their high stability. So we can conclude that Bi₁₉S₂₇I₃ semiconductor nanomaterials have good photoelectric detection performance.