Preparation And Electrochemiluminescence Behavior Of Nitrogen-doped Graphene

The electrochemiluminescence (ECL) analysis has wide application, due to its high sensitivity, fast analysis speed, good controllability, and so on. The preparation of the nitrogen-doped graphene (NG) is a research spotlight, since the NG has excellent photoelectrical property, and could be used in nano electronic devices, biosensors, energy sciences and other fields.In this thesis, the NG was respectively combined with nanoparticles and Two-photon absorption (TPA) complex by absorption, covalent bonding and layer-by-layer assembly. The ECL sensors were constructed with the composites as-prepared. The morphology and constituents of the composites were characterized. Based on the electrochemical property and ECL behavior of the composites, the sensor as-constructed was used to detect samples.Main work is as follows:1. Perparation and ECL behavior of nitrogen-doped graphene/CdTe quantum dots compositeA novel approach of ECL enhancement was developed by combining CdTe quantum dots (CdTe QDs) with nitrogen-doped graphene (NG). The ECL sensor was assembled by coating the NG/CdTe QDs composite as-prepared on the surface of glass carbon electrode. The products (NG, CdTe QDs and composites) were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, ultraviolet visible spectrophotometer, fluorescence spectrophotometer and fourier transform infrared spectrometer and the Nyquist plots of electrochemical impedance spectroscopy, respectively. The ECL mechanism and effect factor were discussed. The results show that the as-prepared sensor has high ECL intensity, long-time ECL stability and good biocompatibility. The ECL sensor was used to detect scorbic acid (AA), and the linear ECL response for AA concentration is from 0.04 μM to 200 μM, with the detection limit of 0.015 μM.2. Perparation and ECL behavior of sulfur-terminal CdS2L complexA novel sulfur-terminal CdS2L complex was prepared by a solvothermal synthesis. The test results show that the CdS2L complex has excellent ECL property in presence of S2O82-. By comparing the ECL property with TPA property, the ECL mechanism of the CdS2L complex/S2O82- system was discussed. Based on a strong and stable ECL emission of CdS2L complex, a solid-state ECL biosensor was assembled. It is found that the ECL biosensor has sensitive response to glutathione (GSH). The liner range is from 0.002 μM to 4μM and the detection limit is 0.67 nM for GSH detection. The study results would enlarge the application range of TPA materials.3. Perparation and ECL behavior of nitrogen-doped graphene/sulfur-terminal CdSaL complexThe NG and CdS2L complexes were modified on the surface of glassy carbon electrode by layer-by-layer assembly, to build a new type of ECL biosensor. The biosensor modified with NG/CdS2L complex showed good ECL property. By changing test conditions, both the influence factors and the ECL mechanism of the biosensor were discussed. The test results for samples indicate that the biosensor has a sensitive and rapid response to uric acid. Under optimal conditions, the logarithm of the ECL intensity and the logarithm of uric acid concentration exhibited a linear relationship when the uric acid concentration is from 0.002 to 2 μM.