The Near-infrared Electrochemiluminescence And Chemiluminescence Properties Of CuInS₂@ZnS Nanocrystals

Electrochemiluminescence（ECL）and chemiluminescence（CL）have the advantages of low background signal,high sensitivity,simple equipment and so on.They have been widely used in the fields of commercial biochemical analysis and in vitro diagnostics.The development of new luminophores and systems is a hot spot in the basic research of ECL and CL.However,the high luminescence potential and the overlap of potential or wavelength between different luminophores restrict the development of ECL.And current CL wavelengths are focused on the visible region and usually require strong alkaline conditions.In order to solve these problems,in this thesis,Cu In S₂@Zn S nanocrystals（CIS@Zn S NCs）synthesized in the water phase are used as luminophores,and their properties of near-infrared ECL and CL under neutral conditions have been systematically studied.The main contents are described as below:（MBA,TSC）-CIS@Zn S NCs with near-infrared ECL properties were synthesized with p-mercaptobenzoic acid（MBA）and sodium citrate（TSC）as stabilizers.The effect of oxidation potential of the luminophores and the co-reactant on the ECL luminescence potential was studied.The results showed that,on the basis of the luminophores with low oxidation potential,further selecting hydrazine hydrate（N₂H₄·H₂O）which also had low oxidation potential as the co-reactant could reduce the luminescence potential to 0.45 V and make it to be the main ECL process.The effects of Cu/In feed ratio,surface sulfhydryl stabilizer types,and Zn S shell coating on the luminescence properties of nanocrystalline ECL were further studied.The element composition and surface state of nanocrystals had significant effects on their ECL intensity and ECL potential.（MPA,TSC）-CIS@Zn S NCs were synthesized with mercaptopropionic acid（MPA）and TSC as dual stabilizers.The influence of MPA,TSC,Na₂S and Zn S on the properties of ECL in the synthesis process was investigated through orthogonal experiments.Finally,sufficient ECL only at 0.30 V with the wavelength of 791 nm was achieved in CIS@Zn S NCs.The ECL potential and wavelength of the ruthenium complex[Ru（bpy）₂（dcbpy）]²⁺were about1.20 V and 635 nm,respectively.Taking advantage of the significant difference between the nanocrystal and the ruthenium complex[Ru（bpy）₂（dcbpy）]²⁺（1.2 V,635 nm）in terms of ECL potential and wavelength,a potential-wavelength dual-resolution ECL system was developed.The simultaneous detection of two cancer markers,glycosyl antigen 125（CA125）and prostate specific antigen（PSA）,was initially achieved.（LA,TSC）-CIS@Zn S NCs with near-infrared CL properties were synthesized with DL-lipoic acid（LA）and TSC.N₂H₄·H₂O and superoxide anion(O₂^-·)could respectively inject electrons and holes into the conduction band and valence band of nanocrystals,and they could recombine at the Cu（I）defect site to produce near-infrared CL.Both the preoxidation effect of LA and the oxidation product N₂H₃^·of N₂H₄·H₂O could promote the production of O₂^-·,thereby effectively improving the CL efficiency of the system.The maximum wavelength of the CL system was 824 nm,and the CL efficiency was 0.0155 Einstein/mol.It was the best value among the CL luminophores based on nanocrystal that had been reported so far.The optimal p H value of this system was 7.0,which was conducive to the detection of targets under physiological conditions compared to CL luminophores such as luminol that require a strong alkaline environment.On these bases,two near-infrared CL analysis methods had been developed to realize the highly sensitive detection of ascorbic acid and ascorbate oxidase,respectively.