Research On The SPR Performance Of Ag Doped TiO₂Semiconductor Film

Recently, the sensor technology based on Surface Plasmon Resonance (SPR)has been wildly studied due to its outstanding advantages such as no label, real-timedynamic detection and high sensitivity. In the SPR technique, gold, silver andmulti-layer composite metal films are commonly used. Because of its shortcomingssuch as oxidation, poor adhesion to the prism and high price, the research on asubstitute material of the metal film is of great importance. In this paper, Ag dopedTiO2film is proposed as a substitute for the single precious metal film to overcomethe defects mentioned above and enhance the performance of SPR.The dispersion characteristics of metal film affectsthe sensing property of SPR. Thecommonly used Drude model and Drude-Lorentz model in SPR calculation arebased on dispersion model of semi-infinite metal, thus they cannot preciselydescribe dispersion law of metal film. Therefore,based on the Drude-Lorentz modeland the F-S theory which describes the conductivity of metal film, a model of thinmetaldispersion which revealed the film thickness and the roughness of surfaces wasproposed, and the theory was applied in SPR calculation to discuss the influence ofthickness and surface roughness of the goldfilm on SPR performance. The aboveresearch is of great importance to the SPR calculation.In order to prepare the SPR sensor film of better performance, a systematicstudy on the sol-gel method and the hydrothermal method to prepare powder andthin film of Ag doped TiO2was conducted and then a SPR performance test wasgiven to the film prepared in the sol-gel method, diffraction peaks of sliver andanatase titanium dioxide were founded in the powder, and it showed a betterphotocatalytic effect to degrade the rhodamine B solution with the amount increaseof sliver. It indicated that semi-conductor powder of nano-sliver doped titaniumdioxide was prepared successfully through the sol-gel method. Diffraction peaks ofanatase titanium dioxide were founded in the film of sliver doped titanium dioxideprepared by sol-gel method, but there was no obvious sliver diffraction peak.The particle size of TiO2in the powder prepared by hydrothermal method was smallerthan that of the sol-gel method,and sliver diffraction peak existed in thefilmbutwithnoobvious diffraction peaksof TiO2.The anglemodulation Krechmannsensor structure was adopted to test the SPR performance of thin film prepared bythe sol-gel method. The result shows that there was no obvious SPR phenomenon,this might be caused by the discontinuity of thin film. Although there were somefailings in the experiment, the research results could provide some valuablereferences for such kind of research.