The Construction Of Metal Cluster Luminescent Ordered Aggregates Based On Supramolecular Self-assembly Method

Supramolecular self-assembly uses a variety of non-covalent interactions to build ordered nanostructures,and achieves the coordination of multiple functions of the building elements.Metal nanoclusters(NCs)refer to metal cores consisting of several to hundreds of metal atoms.The surface of metal cores is generally modified by organic ligands and the size is generally<2 nm.It has excellent physical and chemical properties,such as Electricity,magnetism,catalysis,chirality,etc.However,the fluorescence of synthesized coordination clusters at room temperature is weak or nonexistent.Therefore,a means is urgently needed to control the enhancement of fluorescence.Based on the self-assembly strategy,combining silver clusters with different types of small molecular materials not only achieves aggregated induced luminescence(AIE),but also achieves multifunctional coordination.The functional supramolecular materials prepared by silver cluster self-assembly have rich application value and important academic research significance.The main research content of this paper is divided into the following four parts:Part I,the introduction of the research background.The concept of supramolecular self-assembly is introduced,focusing on self-assembly based on various non-covalent forces;the concept,properties,and applications of metal clusters are introduced;the regulation of metal cluster self-assembly is introduced;the mechanism of AIE and the method of inducing the AIE effect of metal clusters are summarized.Finally,the research content and significance of this paper are put forward.Part ?,study on AgqNCs/ethanol luminescent organogels and their temperature sensitive applications.The effects of the concentration ratio of Ag9NCs and ethanol on the aggregation morphology and the kinetic process of gelation were studied.Through a series of basic characterizations,it was proved that the main driving force for the structure of nanofibers constructed by Ag9NCs and ethanol was hydrogen bonding.At the same time,the effects of other organic solvents on the morphology and gelation of Ag9NCs nanostructures were investigated.The fluorescent properties of Ag9NCs/ethanol nanofibers were studied in detail,and the fluorescence to phosphorescence transition could be achieved.At the same time,the luminescent organic gels could be used as temperature detector.Part ?,study on Ag9NCs/succinic acid(SA)self-assembled luminescent hydrogels and their optical applications.It was studied to change the succinic acid concentration to regulate the phase behavior of the aggregates.The characterization by means of FT-IR,XRD,SAXs shows that the main driving forces of self-assembly are hydrogen bonding and ?-? stacking.The response of the fluorescence characteristics of Ag9NCs/succinic acid assembly material to temperature was investigated.The fluorescence of the assembly material showed a good temperature linearity between 20? and 100?.In addition,the lyophilized xerogel powder exhibits outstanding luminous properties,which was used as light conversion materials and commercially available blue and green phosphors.It is made into a white light emitting diode(LED)by mechanical mixing in a certain proportion.Part IV,self-assembled Ag9NCs/hydrochloride(HCl)luminescent nanorods and optical applications.The aggregation morphology of Ag9NCs was controlled by the inorganic acid HCl to achieve fluorescence emission.The morphology and fluorescence properties of the system are affected by factors such as the concentration of HCl and the type of halogen ions.The study found that the morphology can be transformed from nanospheres to nanorods to nanofibers as the concentration of HCl increases.At the same time,the Cl-can improve the stability of Ag9NCs aqueous solution.In addition,the formation of Ag9 NCs/HCl nanorods was promoted by hydrogen bonding and ?-? stacking.The emission of Ag9NCs/HCl nanorods is pH-responsive and can be quenched by adding NaOH to be used as an erasable material.In addition,the excellent fluorescent properties of Ag9NCs/HCl nanorods can be made into phosphors,which are used in LEDs and exhibit outstanding optical properties.