Performance Of Two Kinds Of Perovskite Quantum Dots And A Low Impedance Electrochemiluminescence Immunosensor

Recently,electrochemiluminescence?ECL?has been widely used in biology,medicine,pharmacy and other fields.Because ECL measurement does not require excitation light source,it offers high sensitivity due to low background light interference.Perovskite nanoparticles have received much attention in recent years due to their superior optoelectronic properties.In this thesis,the ECL properties of perovskite materials are investigated.The main research contents are describled as follows:1.ECL of carbon nanotubes?CNTs?modified FAPbBr₃ perovskite quantum dots in aqueous phase and application in detection of dopaminePerovskite quantum dots of FAPbBr₃ have excellent ECL behavior in the aqueous phase.In potential scan in the range of-1.6¹.6 V,FAPbBr₃ quantum dots exhibit a reduction peak and two oxidation peaks.In the presence of carbon nanotubes?CNTs?and anode co-reactant of tri-n-propylamine,the ECL performance of FAPbBr₃ can be greatly improved.The FAPbBr₃ quantum dots and CNTs modified glass carbon electrode was applied to detect dopamine in a linear range of 0.1-20?mol/L,with a detection limit of 0.05?mol/L.2.Study on size effect of CsPbBr₃ quantum dots in aqueous phaseFive sizes of CSPbBr₃ quantum dots,with the diameters of 10,13,15,18 and 20 nm,were synthesized by controlling the reaction temperature.It was shown that CsPbBr₃ quantum dots can be excited strong fluorescence with half-peak width about f 24 nm.As the particle size of CsPbBr₃ quantum dots is increased from 10 nm to 20 nm,the fluorescent emission peak is shifted from 480 nm to 534 nm.And the absorption spectrum due to the 1S exciton transition peak is also shifted to longer wavelength region.With tri-n-propylamine?TPrA?as the anode co-reactant,CsPbBr₃ quantum dots exhibits good ECL performance in aqueous phase.With the increasing particle size of the quantum dots,the ECL intensity is enhanced at lower potential.The half-width of the emission peak of the ECL is about 24 nm.The size-dependance ECL performance of CsPbBr₃ quantum makes it a useful ECL luminophore candidate..3.Electrochemical-signal-amplification strategy for an electrochemiluminescence immunoassay with g-C₃N₄ as tagsSignal amplification for ECL has conventionally been achieved by employing effective matrixes that can accelerate the electrochemical redox processes or carry more electrochemiluminophores.Herein,a convenient signalamplification strategy was proposed for an ECL immunoassay with carboxylated g-C₃N₄ nanosheets as tags and carcinoembryonic antigen?CEA?as the model target via electrochemically pretreating the substrate:a glassy-carbon electrode?GCE?modified with a polymerized 2-aminoterephthalic acid?ATA?film?GCE/ATA?.Bioconjugates of g-C₃N₄ and the signal CEA antibody?Ab₂??i.e.,g-C₃N₄-Ab₂?were immobilized on GCE/ATA via a sandwich immunoreaction to form GCE/ATA-Ab₁-Ag-Ab₂-g-C₃N₄.Electrochemical-impedance spectroscopy and potential-resolved ECL characterization proved that GCE/ATA plays an important role in the electron-transfer resistance(R_et)of the GCE/ATA-Ab₁-Ag-Ab₂-g-C₃N₄ for ECL and that successively scanning GCE/ATA-Ab₁-Ag-Ab₂-g-C₃N₄ from 0 to-1.6V in K₂S₂O₈ and H₂O₂ containing medium could reduce the R_et and bring out 3.3times enhanced ECL at the10th scan cycle compared with that of the 1st scan cycle,which was about 10.2 times the ECL of the GCE/ATA-Ab₁-Ag-Ab₂-g-C₃N₄ in medium containing merely K₂S₂O₈.Inspired by this,direct and successive scanning of GCE/ATA in K₂S₂O₈ and H₂O₂ containing medium was employed during fabrication,which dramatically reduced the R_et of GCE/ATA-Ab₁-Ag-Ab₂-g-C₃N₄ and brought out obviously enhanced ECL responses for selectively determining CEA from 0.1 pg/mL to 1 ng/mL,with a detection limit of 3 fg/mL.