Research On The Design, Synthesis And Performance Of Several Photoluminescence And Electrochemiluminescence Materials Based On Biological Applications

Novel luminescent materials have scientific values and potential applications in display,illumination,telecommunications,anti-fake,biomedical and environmental monitoring,etc.Hence,researching and developing luminescent materials are great significance.For example,organic aromatic materials with the advantages of high luminescence efficiency,flexibility,and low voltage were widely studied;Inorganic luminescent materials whose surface can be easily functionalized possess the properties of color-tunable,large Stokes Shift,high resistance to photobleaching and long luminescent lifetime;In the meantime,these materials also show their disadvantages,for instance,short luminescent lifetimes,biotoxicity,low luminescence efficiency,weak penetrability,high thermal effects,etc.It is a very meaningful research work to synthesize highly efficient,stable,controllable,modifiable and low cost luminescent materials.The main works of this dissertation are as follows:(1)Electrochemiluminescence(ECL)properties and bio-detection application of organic dye molecules were investigated:the ECL behaviors of nitroolefin-based fluorescein in acetonitrile(CH3CN)system and aqueous system were studied,respectively.In the system of acetonitrile(CH3CN),results indicated that nitroolefin-based fluorescein showed reversible reduction peaks on cycling voltammetric(CV)curve and produced ECL emission with the presence of benzoyl peroxide(BPO)as a coreactant.Reduction potential peaks of the substance can be observed in water solution in CV curve,and the intensity of ECL emission is much lower in water than that of ECL in CH3CN solution.However,the ECL properties of nitroolefin-based fluorescein can be used for the detection of cysteine(Cys)by using potassium persulfate(K2S2O8)as a coreactant in aqueous solution.Under optimum conditions,the ECL intensity has a linear relationship with the concentration of cysteine in the range of 10-9 to 10-8 mol L-1 and a detection limit of 4.2×10-10 mol L-1.It has a lower detection limit than the photoluminescence(PL)method.(2)Synthesis of oil-soluble carbon quantum dots and the design of F127/carbon dots composite nanomaterials:oil-soluble carbon quantum dots were synthesized by one step solvothermal method.The PL and ECL properties of oil-soluble carbon quantum dots have been researched.Oil-soluble carbon quantum dots possessed high fluorescence emission,and had multiple luminescence centers.The centers of luminescence were generated by surface defects,topology defects and the size effect of sp2 hybridized carbon cluster.Oil-soluble carbon quantum dots had a typical wavelength dependent feature.As the change of excitation wavelength,the emission peak concentrated in certain points,such as 400,445 and 510 nm,which moved inhomogeneously.In ECL respect,oil-soluble carbon quantum dots produced a high ECL emission by low voltage when they were spread in mixed solvent by using BPO as a coreactant.To combine diagnosis and treat,hydrophobic group on the surface of carbon quantum dots was used to synthesize F127/carbon dots composite nanomaterials.(3)Facile synthesis of high monodispersed EuSe nanocubes and the research of their properties,including controllable edge lengths,size-dep'endent optical and magnetic properties:We use a facile and robust method for the synthesis of high monodispersed EuSe nanocubes with controllable edge lengths in the range of 8-60 nm.The factors,including temperature,additive,the concentration of Eu2+ and Se2-,were investigated to control the edge lengths of EuSe nanocubes.The resulting EuSe nanocubes were characterized by transmission electron microscope,X-ray diffraction,X-ray photoelectron spectroscopy,UV/visible absorption spectra,fluorescence emission spectra,and superconducting quantum interference devices magnetometer.Rising temperature was benefit for crystal nucleation and going against crystal growth,as a result,small nanocubes were gained.The surfactants were used to influence the size of crystal and the growth direction of crystal.Because the special orbits of Eu2+and the quantum size effect of the semiconductor,EuSe nanocubes has unusual optical properties and size dependent of magnetic properties.