| Plasmonic materials refer to a class of metal or semiconductor materials in which free carriers on the surface of nanoparticles generate collective coupling resonance with light of a specific wavelength,which greatly enhances the local field.The near-infrared(NIR)responsive plasmonic materials have attracted considerable attention in the field of optical sensitivity and biosensing because of their good anti-interference performance,excellent tissue penetration ability and negligible photodamage as well as outstanding signal enhancement capability.The plasmon resonance response of metal nanoparticles could be tuned to the NIR region by regulating their anisotropic morphology,thus they are classical NIR-responsive plasmonic materials(e.g.gold nanorods).However,such anisotropic metal materials possess a relatively low optical output coefficient due to their optical polarization dependence.Recently,the semiconductor materials have attracted wide attention due to their excellent NIR plasmon effects caused by the impaction of vacancy.The smaller the size and the higher the doping degree of such materials,the stronger the plasmon resonance effect.They are independence of light polarization,which is expected to solve the above bottleneck problem.Therefore,this dissertation aims to develop a new type of near-infrared responsive semiconductor plasmonic material,propose new synthesis methods and ideas,reveal the mechanism of its near-infrared plasmonic response,and explore its application in the field of optical sensing,which will provide material foundation for next-generation optical sensitivity devices with high-performance.Aiming at these goals,some staged results are as follows:(1)A new method for ultra-fast synthesis of molybdenum oxide quantum dots(QDs)with oxygen vacancies has been developed,and we reveal the intrinsic mechanism of ligand-induced NIR plasmon strong resonance response and explore the structure-activity relationship between ligand concentration and oxygen vacancy.The batch preparation of QDs with uniform size and good dispersion has been successfully achieved within seconds,and its surface coordination competition adsorption mechanism is proposed.NIR fluorescent probe detection of hydrogen peroxide at ultra-low concentrations(3 nM)was realized.(2)Based on the coordination competition adsorption mechanism,a general,sensitive and low-cost visible-NIR colorimetric chiral recognition probe technology is developed in view of molybdenum oxide nanoparticles.We reveal the chiral recognition mechanism of the color difference in the intensity of the NIR plasmon resonance effect induced by the different concentrations of oxygen vacancy and deeply analyze the structure-activity relationship between the chiral molecular configuration and the different concentrations of oxygen vacancy.The universal,low-concentration,and high-sensitivity near-infrared colorimetric detection of such chiral molecules is achieved.(3)On the basis of the structure-activity relationship of chiral molecules,a new method for the simple and batch preparation of spherical micelles of molybdenum oxide QDs with uniform size and chirality dependence is developed.The key mechanism of D-cysteine modification-induced spherical micelle formation is revealed.The performance of micelles to obtain hydroxyl radicals for dye degradation in the absence of hydrogen peroxide is further explored.Furthermore,a new system for NIR colorimetric sensing is established by utilizing the characteristics of its hydrogen bonds.(4)A rapid and controllable synthesis method of monodispersed gold nanoparticles with dendritic shells is developed.The growth and evolution mechanism of the dendritic shell formed by the accumulating of a large number of small gold nanoparticles is revealed,and the strong NIR plasmon resonance effect caused by the dendritic shell is explored.The insensitive polarization dependence of the structure is discovered,which possesses important application prospects in the fie lds of photoacoustic imaging and photothermal conversion.In this dissertation,a series of fabricating methods for ligand-induced infrared plasmonic materials are developed,and their optical properties are explored.The related sensing mechanisms of the NIR-response characteristics have been established,which lay material foundation for the applications of NIR-responsive plasmonic materials in biological sensitivity... |
