Enhancement Of The Photoelectric Performance Of TiO₂/ZnO Dye-sensitized Solar Cells By Surface Plasmon Resonance Effect Of Ag

As one special kind of solar cells, dye-sensitized solar cells (DSSC) have received greatattention because of their low cost, simple fabrication on large-area flexible substratescompared to traditional silicon solar cells. Recently the overall photoelectric conversionefficiency of DSSC has reached as high as15%. However, further improvement is stillrequired for actual application. The light utilization of anode directly affects the photoelectricproperties of DSSC. The semiconductor materials of anode mainly absorb the ultraviolet.After dye sensitization, absorption range can be extended to the visible light region. But theoverall absorption is still low. Surface plasmon resonance effect of Ag nanoparticles is onepromising approach to improve the light absorption. It is by the Ag nanoparticles efficientlyscattering and trapping the incident light to enhance the absorption of dye and lead to improvethe photoelectric performance of DSSC. But the usual methods of metal nanopartilesfabrication are relative complex and time-consuming. In order to further simplify thepreparation process and save time, in this thesis we explored a quick preparation method todeposit Ag nanoparticles on the anode to enhance the photoelectric properties of DSSC.In this paper, we used TiO2films and ZnO nanorods as the anode, compared the influenceon the cell performance of Ag nanoparticles deposited by two different methods, and in theprocess we researched the optimal loading amount of Ag nanoparticles.Using doctor-blade method prepared mesoporous TiO2film on conductive glasssubstrates. The thickness of the TiO2film was about10μm. Then Ag nanoparticles weredeposited on the TiO2film by reduction of Tollens’ reagent and AgNO3with glucoserespectively. The experiment results showed that by reduction of Tollens’ reagent with glucose,when the concentration of Ag+was1mM and the reaction time was1min, the conversionefficiency of the DSSC reached the best value of5.2%, increased by23%compared with theDSSC based on the pure TiO2film (4.3%). The reduction reaction of AgNO3with glucoserequired reaction time for20min, the DSSC with TiO2/Ag film which was immersed in50mM AgNO3got the best conversion efficiency4.9%increased by12%.We fabricated the ZnO nanorods by Sol method. The length of ZnO nanorods was about2μm and the rod diameter was about100nm. The experimental results by reduction of Tollens’reagent with glucose show that, the DSSC with the ZnO nanorods which was immersed in0.1mM Ag+solution for1min as anode reached the best photoelectric conversion efficiencyof0.31%, which increased by55%compared with the DSSC based on the pure ZnO nanorods(0.2%). In the reduction reaction of AgNO3with glucose, the DSSC with ZnO/Ag which wasimmersed in1mM AgNO3solution for5min got the best conversion efficiency0.27%increased by35%.Depositing Ag-NPs on the electrode by silver mirror reaction can reduce the consumption of AgNO3and greatly save more reaction time. Besides, this reaction could take place at roomtemperature, doesn’t need harsh condition. Moreover, it can more effectively improve theconversion efficiency of solar cell. This rapid and effective method provided a new approachto fabricate the plasmon enhanced dye-sensitized solar cells.