Study On The Photochemical Performance Of Dye-sensitized Solar Cell Based On Metal Ion Doped TiO₂

Dye-sensitized solar cells (DSCs) are considered to be apromisingrenewable source of nonpolluting energy because of their low-costmanufacturing process and high-power conversion efciency. Nano-TiO2film as the support of the dye molecules and the carrier of thetransmission is a very important part in DSCs. In this thesis, we studiedthe preparation of three different metal-doped TiO2nanocrystallineparticles and their applications as the photoanode of the dye solar cells,measuring the impact of different metal doping on the optical andelectrical properties of the battery. The main contents and researchachievements are as follows:(1) In this thesis, Magnesium (Mg)-doped TiO2nanoparticles wereprepared through hydrothermal method. The flat band and electron transport and the performance of photochemical in the Mg-doped TiO₂film electrodes have been investigated by Mott-Schottky and the intensitymodulated photocurrent spectroscopy (IMPS) photocurrent andphotovoltage curves analysis methods. The study found that theMg-doped TiO₂flat band shows a negative shift, which can lead to anincrease of open–circuit voltage (Voc).The results of Intensity modulatedphotocurrent spectroscopy (IMPS) show that the electron transport rate isfaster in the Mg-doped TiO₂electrodes than pure TiO₂. The fastesttransmission time2.27ms was obtained by Mg1%(molar ratio) dopingconcentration. Both the short circuit current and photovoltage have beenimproved by three kind of doping concentration. The photoelectricalconversion efficiency of7.36%DSSC based on pure TiO₂film electrodewas obtained. The highest photoelectric conversion efficiency of8.46%of DSSC based on1%Mg-doped TiO₂film was obtained.(2) Antimony (Sb)-doped TiO₂nanoparticles were synthesized andas the work electrode of determination of flat band potential. It was foundthat the flat band potential shows a positive shift in the Zr-doped TiO₂film compared to pure TiO₂, which result in an improvement onshort-circuit photocurrent and a decreased slightly in open circuitphotovoltage. Furthermore, IMPS measurement shows that the electrontransport rate is faster in the Sb-doped TiO₂electrode compared toundoped TiO₂, which also contributes to increase the short-circuitphotocurrent. Integrated the results of photoelectric conversion efficiency of DSSC based on Sb-doped TiO₂, we demonstrate that1%Sb is theoptimal doping concentration and obtained a photoelectric conversionefficiency of8.13%.(3) Zirconium (Zr)-doped TiO₂nanoparticles were synthesized andas the work electrode of determination of flat band potential. The resultsshow that the flat band potential shows a negative shift in the Zr-dopedTiO₂film compared to pure TiO₂, which have positive influence onimprove the open circuit photovoltage. DSSC fabricated with0.5%Zr-doped TiO₂electrode show higher photoelectric conversionefficiency of7.83%compared to other doping concentration.