Preparation Of CuNCs/LDHs Composite Materials With Excellent Fluorescence Properties And Exploration Of Their Applications

Metal nanoclusters with unique and superior physical and chemical properties are a kind of promising materials.Compared with traditional fluorescent material such as organic dyes and quantum dots,nanoclusters have some advantages,such as the broad stoke shift and good biocompatibility.Thus nanoclusters are widely used in fluorescent sensing,cell imaging,etc.Researchers gradually come into notice the non-precious CuNCs because CuNCs are significantly cheape,earth-abundant and widely used in industries.CuNCs are currently most intensively studyed due to their simple synthesis methods,ultrasmall diameters and wonderful biocompatibility.But researches on applications of CuNCs are still in a preliminary phase because of their low luminous efficiencies and poor storage stabilities.Layered double hydroxides(LDHs)are a typical kind of 2D layered materials.LDHs with rigidity laminate can be exfoliated into ultra-thin nanosheets with positively-charged.In my work,composite materials with ordered structures and multifunctions are prepared,in which LDHs are used as host and CuNCs are used as guest.The composite materials possess excellent fluorescence properties for the confinement effect derived from LDHs and the host-guest interaction,further verified by theoretical studies.The detailed experiments and conclusions are described as follows:1.Based on the the confinement effect derived from LDHs interlamination and the host-guest interaction,we fabricated(CuNCs/LDHs)n films with excellent fluorescence properties by layer-by-layer self-assembly process.The films have uniform morphologies and regular structures.And compared with original CuNCs,the(CuNCs/LDHs)n films have higher emission intensities,improved quantum yields(2.56%to 16.66%),prolonged lifetimes(1.165 ?s to 9.053 ?s)and better storage stabilities.Theoretical studies are performed to confirm the interaction between LDHs and CuNCs.Besides,the(CuNCs/LDHs)n films show well photoluminescence(PL)and electrochemiluminecence(ECL)responses to temperature,indicating that the(CuNCs/LDHs)n films have potential in the fields of optical display and temperature sensor.2.Based on the the confinement effect derived from the surface of LDHs lamination and the host-guest interaction,we prepared CuNCs/LDHs sol-materials with excellent fluorescence properties.Compared with original CuNCs,the CuNCs/LDHs sol-materials have higer emission intensities,improved quantum yields(2.56%to 16.38%)and prolonged lifetimes(1.165?s to 8.133 ?s).As contrast,we prepared different composite materials,and the results suggesting that LDHs provide confinent effect and there are interactions between LDHs and CuNCs.And emission intensities of different CuNCs/LDHs nano-materials are different for the different energy bands.Besides,the CuNCs/LDHs sol-materials are used to cell imaging.The CuNCs/LDHs sol-materials are gathered in the cytoplasm.Compared with CuNCs,the imagings of CuNCs/LDHs sol-materials are more clearness and more stable,suggesting that CuNCs/LDHs sol-materials can be widely used in the field of cell imaging.These works offer novel ideals of strcture design and preparation method to prepare composite materials for CuNCs,and make some helpful progress to improve the properties of CuNCs.