The Preparation Of Rare Earth Down-conversion Film And Its Application In Dye-sensitized Solar Cells

Dye-sensitized solar cell(DSSC) has the advantages of lower production cost, simply preparation process, weak influence by temperature and so on, which is a promising type of solar photoelectric conversion device. The nanocrystalline TiO2 photoanode is the key part of DSSCs, which playing a part in dye molecules adsorption, providing electron-hole separation places and transmission electronic. Therefore, properties of nanocrystalline TiO2 photoanode determine the photoelectric conversion performances of DSSCs ultimately. Without modification, nanocrystalline TiO2 photoanode is not ideal, which makes the modification of nanocrystalline TiO2 photoanode becoming the research hotspot of DSSC. Spectral response range of nanocrystalline TiO2 dye-sensitized is mainly concentrated in the range of visible light and the UV absorption rarely. Therefore, converting the UV not absorbing by DSSCs to visible light absorbing by DSSCs can improve the sunlight utilization rate of DSSCs in a large extent, which improving the photoelectric conversion efficiency.This paper used TiO2 as the down-conversion medium material, Sol-Gel method had been used to prepared TiO2 doped rare earth down-conversion film, discussed the conversion characteristics of TiO2 doped rare earth down-conversion film and its power under UV light, the effects of Sm3+, Eu3+ and Y3+ with different doping concentration on the down-conversion performance and different layers on the photoelectric properties of DSSC. XRD, EDS, PL, UV-Vis had been used to tested the samples. Using the solar simulator(SSA50), Keithley Source Meter instrument(Keithley2400) to test the photoelectric properties of DSSCs. The specific contents are as follows:(1) The TiO2︰Sm3+ down-conversion film has been prepared by a Sol-Gel method 540-600 nm wavelength visible light can be emitted when the TiO2/Sm3+ film was exposed to 395 nm ultraviolet light, which showed a down-conversion feature of the film Double-layer TiO2︰Sm3+ down-conversion film can keep a visible light transmittance comparable to that of single phase TiO2 film. However, short circuit current(Jsc) was increased by 13.2% and photoelectric conversion efficiency(Eff) by 16.2% with down-conversion feature of TiO2/Sm3+ film when rare earth content was 1%.(2) TiO2 ︰ Eu3+,Y3+ down-conversion film was prepared by Sol-Gel method and applicated in dye-sensitized solar cells. Exposed to 396 nm ultraviolet light, down-conversion film could emit 535-620 nm wavelengths visible light which showed a down-conversion feature of the film. Double-layer down-conversion film still kept a higher visible light transmittance compared with a single phase TiO2 film. When total rare earth content was 4%, short circuit current(Jsc) was increased by 21.5% and photoelectric conversion efficiency(Eff) by 14.1% with down-conversion feature of TiO2︰Eu3+,Y3+ film.