Application Of The Rare-Earth Luminescence Materials In Dye-Sensitized Solar Cells

The solar energy is clean and will be never used up. To effectively use the solarenergy is a good way to the settlement of energy crisis and environment pollution.Thesolar cell is a device to change solar energy into electric energy. Since the thirdgeneration of the solar cell-thedye-sensitized solar cell（DSSC） was first reported, ithas aroused much interest of many researchers. Currently, the light-to-electric energyconversion efficiency of the DSSC has reached more than12%. How to furtherenhance the conversion efficiency and reduce the production costs are the objectivesof many researchers. At the same time, it is an effective measure to solve the energyproblem. Presently, there are many measures to increase the efficiency of the DSSC,such as the optimization of the DSSC structure, including preparing a new n-typesemiconductor, synthesizing new dyes, and preparing new electrolyte. Moreover,enlarging the spectrum of the dyes in the DSSC, can also effectively enhance theefficiency of the DSSC. At present, most of the dyes only absorb light in the range of300-800nm, so it makes sense to take full advantage of the infrared light andultraviolet light.In this paper, up and down conversion luminescence materials were synthesizedusing high temperature calcination process, hydrothermal-calcination method, andhydrothermal method, with YF3and Y2O3as the host materials. Then, they wereadded into the DSSC. As a result, the spectrum range of incident light was increased,the flatband potential was shifted, the Femi level and the open-circuit voltage of theoxide film was heightened, and the conversion efficiency of the DSSC was enhanced.（1）YF3:(Yb³⁺, Er³⁺) nanocrystals were prepared using calcination process andwere introduced into TiO2electrode in the DSSC. As a luminescence medium,YF3:(Yb³⁺, Er³⁺) improved the infrared light harvesting via up-conversionluminescence process and increased the efficiency. When the doping amount ofYF3:(Yb³⁺, Er³⁺)/TiO2in doping layer is optimized as7wt.%, the photovoltaicconversion efficiency of the DSSC reached7.90%, increasing by35%compared tothat of a DSSC without YF3:(Yb³⁺, Er³⁺) dopant. Under the infrared irradiation of 33mW·cm^-2, the conversion efficiency of the DSSC increased from0.055%to0.226%.（2）Y2O3:Er³⁺nanorods were synthesized using hydro-thermal method followedby a dehydration process. Then they were introduced into the TiO2electrode. TheXRD, SEM, TEM, HRTEM, SAED, EDS, excitation spectrum, and emissionspectrum of the Y2O3:Er³⁺nanorods were presented in the paper. When the dopingamount of Y2O3:Er³⁺nanorods was5wt.%, the energy conversion efficiency of theDSSC reached7.004%under a simulated solar light irradiation of100mW·cm^-2,enhancing by a factor of20%compared to that of the DSSC without Y2O3:Er³⁺dopant. Under the infrared irradiation of33mW·cm2, the energy conversionefficiency of the DSSC enhanced from0.055%to0.168%.（3）YF3:Eu³⁺nanocrystals were prepared using hydrothermal method. When thedoping amount of YF3:Eu³⁺was5wt.%in the TiO2film, the conversion efficiency ofthe DSSC reached7.741%, increasing by a factor of32%compared to that of theDSSC without YF3:Eu³⁺dopant. Under the ultraviolet irradiation of24mW·cm2, theenergy conversion efficiency of the DSSC increased from0.373%to0.557%.