The Research And Application Of Photoelectrochemical Sensing Technology Based On Nanometer Semiconductor Photosensitive Materials

With the rapid development of society,people pay more and more attentions to the healthy living environment and the early prevention of disease.More and more attentions are paid to the detection of pollutants in agricultural products and the early prediction of tumor markers.The construction of photoelectrochemical sensor is an analytical method based on the photoelectric conversion performance and chemical,biological recognition process.The photoelectrochemical sensor can reduce the background signal and improve the sensitivity of the detection because of the effective separation of the excitation signal and the detection signal.In addition,photoelectric chemical detection has certain practical value and application potential,owing to its advantages of simple,inexpensive and easy to operate.As a new analytical method,photoelectrochemical sensor analysis has become a research hotspot in environmental monitoring and immune analysis.And photoelectrochemical sensor analysis getting more and more attention with the continuous efforts of people.The key of photoelectrochemical sensor is to promote the photoelectric conversion efficiency.Moreover,the preparation of nanometer-class semiconductor photosensitive materials with high photoelectric conversion efficiency and its application in photoelectrochemical sensor became an important direction of research.The main task of this paper is to prepare high semiconductor photosensitive material with high photoelectric conversion efficiency and study its application in photoelectrochemical sensors.1.A label-free photoelectrochemical sensor based on TiO₂/S-BiVO₄@Ag₂S nanocomposite was fabricated.Titanium dioxide nanoparticles had good photoelectric activity and large ratio surface.The S-BiVO₄ was a porous surface structure with red blood cell-like shape,which can promote photocurrent intensity under visible-light irradiation.In addition,Ag⁺was developed on surfaces of thioglycolic acid modified S-BiVO₄,further enhancing the photocurrent response and improving the efficiency of photocurrent conversion.Under the photochemical detection optimum condition,the assembled sensor successfully realized the sensitive detection of ochratoxin A.2.The construction of photoelectrochemical sensor based on competitive strategy to detect aflatoxin B1.The nanoflower WO₃ with porous structure and large specific surface area was as substrate material for the immobilization of BSA-AFB1 on the electrode surface.The Ag⁺-functionalized bismuth vanadate nano-polyhedron（BiVO₄@Ag⁺）was utilized as labels for immobilization anti-AFB1 through affinity specific binding.The Ag₂S was prepared in-situ growth by immediately deposition the S^2-onto the BiVO₄@Ag⁺.The high photocurrent intensity was obtained by the generated BiVO₄@Ag₂S under visible-light irradiation.The characterization methods of XRD,SEM,TEM were used to prove the successful preparation of semiconductor photosensitive material.Under the optimal experimental conditions,the competitive photoelectrochemical sensor realizes the quantitative detection of aflatoxin B1.3.A new,photoelectrochemical immunosensing platform was established on the basis of La-CdS/3D ZnIn₂S₄/Au@ZnO sensitization structure for detection of aminoterminal pro-brain natriuretic peptides（NT-proBNP）.The Au@ZnO-modified electrode was first assembled with3D ZnIn₂S₄,and then further deposited with lanthanum doped cadmium sulfide（La-CdS）via successive ionic layer adsorption and reaction strategy.The Au@ZnO had excellent photoelectric activity and good electrical conductivity.The ZnIn₂S₄ with 3D architectures not only exhibited high photocurrent intensity under visible-light irradiation but also had large surface for the deposition of La-CdS.Meanwhile,the La-CdS doping structure could depress the charge recombination,which effectively promoted separation of the generated electron-hole pairs and consequently enhanced the photocurrent conversion efficiency.The polydopamine（PDA）was used not only as a cross-linker reagent for the immobilization of the anti-NT-proBNP but also as an electron donor for promotion the photo-generated electron-hole separation.Under the optimal conditions,the well-designed photoelectrochemical sensor exhibited successfully detection of NT-proBNP.