Electrochemiluminescence Of CsPbBr₃ Perovskite Nanocrystals And Its Application

Electrochemiluminescence（ECL）is a kind of analytical method which combined with the characteristics of electrochemical and chemical luminescence.And ECL analysis has great potential in analytical application due to its high sensitivity,good selectivity and wide linear range.Semiconductor nanocrystals（or quantum dots）with a certain size is a kind of significant ECL light emitters.Since Bard and co-workers reported the ECL of Si NCs in2002,the study on the property and application of quantum dots has drawn great attention.However,because of the biological toxicity of semiconductor quantum dots and the low ECL efficiency of carbon quantum dots,the development of new type quantum dots with excellent ECL performance is the key problem to study the ECL applications.Recently,as a new kind of nanomaterials,perovskite nanorytals has attracted wide attention.Since Kovalenko and co-workers demonstrate a new method for all-inorganic halide perovskites at 2015,the characteristics and application of all inorganic perovskite quantum dots have been developed rapidly because of its excellent fluorescence and electrochemical properties.Nevertheless,there almost no research of the ECL property and application of the perovskite quantum dot has been developed.Herein,the ECL properties and applications of CsPbBr₃ perovskite quantum dots were studied.The main works are as follows:1.Monochromatic and electrochemically switchable electrochemiluminescence of perovskite CsPbBr₃ nanocrystalsCubic-shaped perovskite CsPbBr₃ nanocrystals（NCs）could be electrochemically injected with holes（or electrons）to produce several charged states under different oxidizing and reducing potentials,and then bring out electrochemiluminescence of higher color purity than traditional ECL chemicals and metal chalcogenide NCs,in both annihilation and co-reactant routes.The difference of electrochemical gaps between varied hole and electron injecting potentials displayed little effect on the ECL spectrum and colour purity of CsPbBr₃ NCs.All the excited states generated under different oxidizingand reducing potential couples in ECL of CsPbBr₃ NCs were the same as those in photoluminescence,as all the ECL spectra were almost identical to the CsPbBr₃ NCs ’photoluminescence spectrum.Importantly,the ECL of CsPbBr₃ NCs was electrochemically switchable and displayed an obvious “on/off” type feature by changing the sequence of hole injecting and electron injecting processes,as strong ECL could be obtained by injecting holes onto the electron injected NCs,while no or very weak ECL was obtained in the reversed way.2.Hydrogen peroxide involved carrier recombination for anodic electrochemiluminescence of perovskite CsPbBr₃ nanocrystals in aqueous mediumThe electrochemical involved carrier injection and recombination of perovskite CsPbBr₃nanocrystals（NCs）in aqueous medium was investigated for the first time with ECL techniques.The CsPbBr₃ NCs was physically deposited onto the surface of glassy carbon electrode（GCE）and demonstrated desired stability for carrier injection and recombination processes in aqueous medium.The CsPbBr₃ NCs could be electrochemically injected with holes,while carrier recombination could be simply achieved at NCs surface with the presence of H₂O₂,or some electrochemically generated reactive oxygen species.Importantly,the carrier recombination was highly selective to H₂O₂,and could bring out efficient and highly monochromatic ECL at anode.The promising carrier recombination process of CsPbBr₃ NCs in aqueous medium might opened the way to design the biochemicals involved optoelectronic and photovoltaics devices with perovskite NCs as models,and be used to develop bio-related and highly color-selective ECL sensing strategies.3.Spectrum-based ECL sensor with CsPbBr₃ NCs as labelsThe spectrum-based ECL sensor in aqueous medium with CsPbBr₃ NCs as labels was investigated.The surface ligands of CsPbBr₃ NCs were oleamine and oleic acid,indicating that CsPbBr₃ NCs were highly passivated,and all the ECL spectra were almost identical to the photoluminescence spectrum of CsPbBr₃ NCs.Based on the excellent monochromatic and electrochemically adjustable properties of the Cs PbBr3 NCs,and dopamine（DA）had a quenching effect on the ECL spectra of CsPbBr₃ quantum dots,so we applied CsPbBr₃ NCs in detecting dopamine.