| Electrochemiluminescence?ECL?analysis technology inherits the characteristics of both electrochemical and chemiluminescence.It has the advantages of fast response,high sensitivity,good controllability,low background signal,and so on.ECL is emitted by a luminophor excited to transition to an excited state and then returned to a ground state.The process of transforming the luminophor into excited state is as follows:One is that a new substance provides energy to cause the luminophor to transition from the ground state.The other is that the electrode provides energy to cause the luminophor to undergo a redox reaction.The traditional ECL materials?luminol,quantum dots,and terpyridine ruthenium?show some disadvantages,such as complex preparation process,difficulty in modifying and immobilization.Polycyclic aromatic hydrocarbon organic materials have excellent photoelectric performance and high fluorescence quantum yield due to their large?-?conjugated system.Therefore,PAH organic materials have great research potential in the field of ECL.In the current work,three new ECL materials,rhombus-shaped rubrene microsheets,sulfur-functionalized zirconium metal organic frameworks,and conjugated microporous polymer films were synthesized.The ECL properties and mechanisms of these materials are investigated,and they are prepared to the sensor for highly sensitive detection of small molecules.The research of this paper is mainly carried out in the following three parts:1.The research on the construction of highly sensitive electrochemiluminescence L-cysteine sensor based on platinum-rhombus-shaped rubrene microsheetsHere,a ternary ECL system based on platinum nanoparticles?PtNPs?,rhombus-shaped rubrene microsheets?RubRMs?and dissolved oxygen?O2?is proposed.First,RubRMs are prepared by reprecipitation method,and then PtNPs are reduced in situ on the surface of RubRMs by a simple method to synthesize PtNPs-RubRMs metal-organic composites.With the help of L-cysteine?L-Cys?,dissolved oxygen in the rubrene/oxygen system and active oxygen generated in the ECL process can be consumed,thereby quenching the luminescence signal,and an"on-off"type of ECL sensor realizes quantitative analysis of L-Cys.In composite materials,RubRMs have a large specific surface area,which provide more sites for the reduction of PtNPs,and the PtNPs not only catalyze the decomposition of dissolved oxygen,but also accelerate electron transfer,making the sensor show high sensitivity.It has a good linear response in the concentration range of 1.0×10-9 mol?L-1?5.0×10-4mol?L-1,and the detection limit is 3.3×10-10 mol?L-1?S/N=3?.2.The research on electrochemiluminescence analysis based on sulfur-functionalized zirconium metal organic framework for epinephrine sensorHere,the sulfur-functionalized zirconium?IV?-based metal-organic frameworks?Zr-MOFs?with high luminous efficiency as a novel ECL emitter is used to construct the biosensor for sensitive detection of epinephrine?EP?.Compared to the ligand with the aggregate state as the luminophore,the Zr-MOF with porous structure can relieve the ECL aggregation-caused quenching?ACQ?effect,resulting in an enhancement of ECL intensity.Impressively,the well-dispersed coreactant tripropylamine-modified gold nanoparticles?TPrA@AuNPs?are adsorbed on Zr-MOFs to form the composite?TPr A@AuNPs/Zr-MOFs?,which can significantly increase the local concentration of the coreactant on the electrode surface,shorten the electron transport distance between the coreactant and the luminophore,reduce the energy loss during the reaction and further improve the ECL efficiency of the Zr-MOFs/TPrA ECL system.The experimental results show that the ECL intensity of Zr-MOFs is about 1.5 times that of the aggregated ligand,and the ECL efficiency of the Zr-MOFs/TPrA system is increased by 1.8 times due to the enrichment and immobilization of the coreactant on the electrode surface.Considering above advantages,the biosensor for the detection of EP exhibits the linear range from 1.0×10-8 to 1.0×10-2 mol·L-1 with a detection limit of 3.3×10-9 mol·L-1?S/N=3?.This strategy devises a method to improve the ECL efficiency of luminophore for the construction of efficient biosensors to detect biomolecules.3.The research on electrochemiluminescence analysis based on conjugated microporous polymer films for dopamine sensorsHighly hydrophobic polycyclic aromatic hydrocarbon nano or micro materials with unique optical properties have received great attention in the field of electrochemiluminescence?ECL?.However,these illuminant materials with tight molecular arrangement and excess inactive emitters do not utilize the activated coreactant efficiently,resulting in lower ECL efficiency of these materials.Here,2,6-Di?9H-carbazol-9-yl?anthracene-9,10-dione?CAD?is used as an electroactive precursor to prepare ECL conjugated microporous polymer?CMP?films by electropolymerization?EP?,which combines two carbazole groups as electron donors and one anthraquinone as electron acceptor.Carbazole is a highly electroactive group with a lower potential.Oxidative coupling can occur between carbazole groups by applying a certain anode potential.This characteristic of the carbazole group enables the structure and properties of CMPs films to be precisely controlled by EP.In sharp contrast to the single CAD molecule and the CAD microcrystals prepared by the reprecipitation method,the stable,highly cross-linked amorphous CAD-CMP films prepared by EP show strong and stable near-infrared ECL emission in an aqueous medium contained triethanolamine?TEOA?as a coreactant.The thin films can be prepared on electrodes with high quality,and the ECL strength of the CAD-CMP films can be adjusted with their thickness.The sensor prepared by the CAD-CMP films to detect dopamine shows high sensitivity,with a linear range of 1.0×10-10?1.0×10-4 mol?L-1,and a low detection limit of 3.3×10-11 mol?L-1?S/N=3?.As a new generation of ECL material,CAD-CMP films have shown broad prospects in the field of ECL sensor device manufacturing and ECL imaging. |
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