| During the past decades, as a family member of semiconductor nanomaterials, transitional-metal chalcogenides nano-semiconductors have been attracting much attention owing to their peculiar structures and excellent properties. Ag2Mo3010-1.8H20nanowires and β-AgVO3nanobelts are two semiconductors, which have band gaps of about2.8eV and2.5eV, respectively. Intense absorption peaks can appear in the visible-light region for these two nanostructures. Tunale optical properties can be obtained, such as luminescence, photo catalysis and surface-enhanced Raman scattering (SERS) properties, with the help of photo irradiation to modify the surface structures of these nanomaterials. Excellent electrical conductivities make them useful in nano-electronics, for example field-effect transistors based on semiconductor nanostructures (nano-FETs). Their perfect anti-bacterial and gas sensing properties could make them potentially be used in food industry.Magnetic greigite (Fe3S4) nanocomposites, as a member of nanosemiconductors, can exist in the nature; however, they are always synthesized by the magnetotactic bacteria, which inhabits on the bottom of sea and lakes without no oxygen. This work introduces a simple solvent-based synthetic method, which can prepare a large scale of water-soluable Fe3S4nanocomposites. The presence of β-CD and PEG make them water-soluable, stable and biocompatible; as a result, they have potential application in biomedicine. As a ramification semiconductor of iron sulfides, the iron sulfide-amine hyrids have low band gaps and peculiar sandwiched structures, In this work, we demonstrated that they have exhibited changing morphologies, structures and magnetic properties with the variation of amine molecules. As a result, these hybrid semiconductors have potential application in magnetism devices owing to the tunable magnetic properties. The main results can be summarized as following:1. Ultralong one-dimensional Ag2Mo3010·1.8H2O nanowires can also be obtained by the facile hydrothermal synthesizing method, which have been characterized with XRD, SEM and HRTEM. TG-DTA analysis show the phase stability at selevtive temperatures; and photo irradiation on the nanowires help obtain the photo stability properties. Interestingly, a large amount of silver nanooparticles can be obtained by heating or photo irradiating the nanowires. Furthermore, we appove that photo irradiation can be an effective way of modifying the surface strutures of nanomaterials to get excellent properties. Besides, with the interesting optical properties, the nanowires with and without photoirradiation have potential application in many areas, such as optical materials, photocatalysis and SERS substrates. In addition, their perfect electrical propertie of a single nanowire makes these materials potentially be used in microelectronics or microsensors.2. According to the special electrical properties of β-AgVO3nanobelts and Ag2Mo3O10nanowires in previous works, electrics devices such as nano-field effect tubes (FETs) have been established with a single nanobelt and a nanowire. As to the silver based lamellar oxides, silver cations in the special structures can be able to move under appropriate conditions, which result in their conductivity. Notably, single β-AgVO3nanoblelt has been found to exhibit better conductivity than single Ag2Mo3010nanowire. Therefore, it is worthy to perform further experiments to control the conductivity of β-AgVO3nanoblelts by investigating several relative and important factors. All the results can confirm that both nanomaterials would have potential applications.3. Solvethermal method has been utilized to obtain a large scale of water-solubale Fe3S4nanocomposites (NCs). As-prepared Fe3S4NCs show high crystalline and excellent stability in the atmosphere. Through the magnetic measurements, the NCs exhibit ferromagnetic behavior. In the presence ofβ-CD and PEG, the NCs own wonderful water-solubility and biocompability; as a result, they have potential application in biomedicine, such as magnetic resonance imaging (MRI) and cancer inhibition.4. A large scale of molecule template-directed iron sulfide-amine hybrid semiconductors with low band gaps, sandwiched structures, and magnetic properties can be synthesized by a facile solvothermal method. X-ray absorption fine structure (XAFS) technique has been utilized to analyze the structural evolement and the results display the decrease of iron-amine complexing and increase of independent amine molecules. With the variation of amine molecules in these structures, the hybrid semiconductors show different morphologies, and tunable magnetic properties can as well be obtained with the variation of the structures, which makes it possible to be potentially used in magnetic devices. The magnetic results illuminate that the so-called spin-glass state can be enhanced with the decrease of iron-amine complexs and increase of independent amine molecules. The enhanced spin-glass state plays a crucile rule rather than the ferromagnetic behavior at low temperatures, which leads to the increasing blocking temperatures and coercivities. |
PDF Full Text Request