Study On Preparation And Application Of Chalcogenide Nanosemiconductor Materials

With the progress of human civilization and the development of science and technology,the research and development of nanosemiconductor materials in solar energy development and functional products has attracted extensive attention of scientists because of their special photoelectric properties and photoluminescence properties.On the one hand,semiconductor materials can be excited under a certain wavelength of light to produce electrons with reducing ability and oxidizing ability holes,which makes nano-semiconductor materials can be used in the photolysis of aquatic hydrogen and purification of water pollutants.Due to its unique electronic structure and excellent visible light response ability,a new semiconductor material Cd In₂S₄ has been further developed and applied to the photodegradation of water for hydrogen production and photocatalytic degradation of organic pollutants.On the other hand,quantum dots（QDs）will be excited to produce fluorescence and corresponding color under ultraviolet light irradiation.This unique optical property makes QDs have great potential application value in the development of luminescent materials.Ag-In-Zn S/Zn S quantum dots not only have high fluorescence quantum yield,they are green and non-toxic,but also can be prepared on a large scale.Therefore,further development and application of Ag-In-Zn-S/Zn S quantum dots is of great value.The main research contents are as follows:1.Novel direct Z-scheme CdIn₂S₄/TiO₂ heterojunction was constructed.Nano-Ti O₂was in-situ composite on the surface of Cd In₂S₄ via a practical,template-free hydrothermal method.The photocatalytic performance of Cd In₂S₄/Ti O₂ was studied by measuring the photocatalytic degradation rate of MO.Their structure,morphology and photoelectric effect were studied by XRD,SEM,TEM,XPS,PL,UV-vis DRS and electrochemical measurement.The degradation efficiency of Cd In₂S₄/Ti O₂ photocatalyst is the highest when the loading amount of Ti O₂ is 25wt%.Compared with pure Ti O₂ and Cd In₂S₄,the formation of direct Z-scheme structure between the two components in the composite retains the excellent properties of each component and promotes the overall excellent photocatalytic performance.Through the capture experiment of active substances,it was confirmed that h⁺and·O^2-were the main active substances.Then,combined with the energy band analysis of the complex,a reasonable electron transport model was constructed.2.A layer of MoS₂ was deposited on the surface of flower-like Cd In₂S₄ by a green and simple hydrothermal method to form a Cd In₂S₄/Mo S₂ heterojunction.The effects of different loads on the photocatalytic hydrogen production of Cd In₂S₄ were studied.By comparing the crystal structure morphology and photoelectric properties of pure Mo S₂and Cd In₂S₄,the reasons for the efficient hydrogen production of Cd In₂S₄/Mo S₂composite were systematically analyzed,and a possible electron transport model was proposed according to the experimental results.3.First,aqueous gelatin-coated high luminescent Ag–In–Zn–S/Zn S QDs with emissions from blue to red region（450–670 nm）are fabricated;the chitosan–glycerin/QDs nanocomposites glue was prepared by adding moderate amount of chitosan and glycerin during physical blending process.Then the novel chitosan–glycerin/QDs nanocomposites thin films（GCG–QDTFs）with high transmittance,flexibility and foldability can be got after drying.By controlling the relative content of gelatin–chitosan and glycerin as plasticizer in the GCG–QDTFs,the transmittance,solubility,moisture absorption and mechanical properties were tested respectively to explore the influence of variables on the properties.The properties of the novel quantum-polymer composite anti-counterfeiting film’s application on glasses,and plastic bag were further investigated.