Monochromatic Electrochemiluminescence Of Ce??? Doped CsPbBr₃ Nanocrystals And Water-Soluble Gold Nanoclusters

Electrochemiluminescence(ECL)refers to the phenomenon of radiation generated by electrochemical means to transition a substance on the surface of an electrode from a ground state to an excited state and then back to the ground state.ECL analysis does not require excitation of the light source,and has many advantages such as high signal-to-noise ratio,high detection sensitivity,wide linear range and wide application prospects.Electrochemiluminophores plays an important role in the development of ECL.In view of the fact that there are few electrochemiluminophores with excellent ECL performance,the development of new electrochemiluminophores has always been one of the important contents of ECL basic research.Studies on the modification of nanoparticles to modulate luminescence intensity and wavelength have rarely been reported.This dissertation includes the following two parts1.Efficient and monochromatic electrochemiluminescence from aqueous soluble Au nanoclusters via host-guest recognition.Inspired by the enhanced photoluminescence of Au clusters(Au NCs)with a rigid shell,herein,forming rigid host-guest assemblies on Au NCs was employed to screen environment-friendly,biocompatible,and efficient electrochemiluminophores for the first time.With 6-aza-2-thiothymine(ATT)protected Au NCs(ATT-Au NCs)and L-arginine(ARG)as models,the rigid supramolecular host-guest assemblies formed between ATT and ARG on ATT-Au NCs surface brought out ART/ATT-Au NCs with modified electrochemical charge-injection processes,and enabled dramatically enhanced electrochemiluminescence(ECL).The aqueous soluble ARG/ATT-Au NCs not only displayed one direct cathodic ECL process around-1.30 V and three anodic ECL around +0.78,0.90 and 1.05 V in a so-called "half-scan" experiment without co-reactant,but also demonstrated 70 folds enhanced oxidative-reduction ECL around 0.78 V than ATT-Au NCs with TPrA as coreactant.Importantly,ECL of ARG/ATT-Au NCs was high monochromatic with maximum emission around 532 nm and width at half-maximum around 36 nm,which was of great interest for color-selective ECL assay.2.Tunable morphology and radiative charge recombination of perovskite CsPbBr3 nanocrystals via Ce4+ doping.The intrinsic ionic properties and flexibility of the perovskite crystal structure make it possible to dope a variety of ions in the host to adjust its properties,which has broad implications for its synthesis,surface functionalization and processing.In this study,Ce4+ doping hinders the crystallization process of the parent CsPbBr3 to form CsPbBr3-Ce4+.As known to us,Ce4+ is easily reacted with ammonia to form CeO2,so Ce4+ doped in CsPbBr3 is taken away and recrystallized to form CsPbBr3-CeO2.During this process,the morphology of the nanocrystals changes from cubic to spherical and then to rectangular.Fluorescence changes from monochromatic(515 nm)to two-color(468 nm and 515 nm)and then to monochromatic(520 nm).The spectral intensity changed from strong to weak to strong,but the wavelength of their ECL spectrum was only 520 nm.The results show that the method is a novel synthesis method with adjustable structure and emission wavelength,which has good competitiveness.