Photoelectrochemical Sensor Using Organic Dyes Sensitized Anode Tuned By Chemical Reaction

Photoelectrochemical?PEC?sensor is a newly developed sensing system based on photon-current conversion whereas the concentration of analytes is quantitatively determined.PEC sensing has attracted extensive interest as a potential sensing platform for chemical and biomolecular analysis mainly due to their desirable low background,high sensitivity,cost-efficiency and simple instruments.It use the light source as the excitation source and the photocurrent as the output detecting signal,in which the change of photocurrent could be measured by the biological interactions between various recognition elements and their corresponding target analytes,then reducing undesired background signals and improving the sensitivity and selectivity of analyting.In the previous research,the studying of photoelectrochemical sensor are focus on the optimization of photoelectric sensor identification unit in electrolyte,and anodes are usually fixed on some semiconductor materials with photovoltaic effects,such as titanium oxide,zinc oxide,which cause interface resistance,causing negative effect to the photoelectric conversion efficiency.In this paper,the main content of our research could be listed in three aspects.Firstly,we focus on the dyes immobilized on photoanode,our sensor is based on the well-developed dye-sensitized photoelectrochemical solar cell.The platform is focus on the photoanode in which the organic dyes with D-?-A structure was immobilized on TiO₂/ITO as biorecogniton element for probing biological molocure and the TiO₂ substrate was used as the signal transducers.Results show that the whole process is no longer limited to the electrode interface process,highly sensitive,quantitative detecting specific biological molecules such as cysteine in a variety of complex environments can be achieved.Secondly,we combine the PEC sensor with DNA sensor,taking advantage of the photoactive transducers or reporters,such devices convert the DNA recognition events into a useful electrical signal,providing an elegant route for probing various mi-RNA interactions at the molecular level.After AuNPs dropped in the nanostructured TiO₂ electrode,we fabricate a photoelectrochemical sensor with Au/TiO₂/ITO as the photoanode.This efficient detection measure presents a low detection limit of 0.12 fM,and can excellently distinguish the mismatched microRNA.Thirdly,the composite of graphene and molybdenum disulfide are used as supercapacitor electrode material by reduction reaction in situ.Moreover,the electrons are getting through different interfaces fastly,which in conclusion,the material is affording the high specific capacitance and good cycling stability during the charge-discharge process.The composite here,not only makes full use of graphene,but also shows the conducting feature of molybdenum disulfide.This extremely novel structure of composite,is now,a very potentional supercapacitor electrode material.The graphene has a high surface area and conductivity,which will be potentional when applied to PEC sensor photoanode.