Preparation Of Upconversion Luminescence Materials Of Y₂O₃:Er³⁺ And Its Application In Dye-sensitized Solar Cells

Dye sensitized solar cells?DSSCs?have attracted much attention because of its low cost,simple preparation technology and high photoelectric conversion efficiency.The nano TiO₂ thin films is a potential alternative for its good stability,high photoelectric conversion efficiency,and low cost.The TiO₂ photoanode as an important part of the dye-sensitized solar cells,it plays an important role in light absorption and electron transmission.The sun light capture,injection and collection of electronic an anwanted electron recombination are all connected with TiO₂ photoanode.Therefore,modifying the nano TiO₂ thin film is necessary to obtain higher photoelectric conversion efficiency.TiO₂ can only absorb sunlight from the ultraviolet region,and the dye sensitized TiO₂ extend it to the visible region,but the most of the infrared light can't be absorbed.So we introduce the upconversion luminescence of rare earth powder,which can convert the infrared light to visible light that N719 can use,thus improving the performance of dye-sensitized solar cells.The research contents and conclusions are as follows:?1?Rare earth upconversion Y₂O₃:Er³⁺ phosphor has been synthesized by hydrothermal method with different morphologies.By adjusting the hydrothermal reaction conditions,such as alkali,alkali concentration and hydrothermal reaction time,nano sheet,rod and the flower like rod were prepared.We use X-ray diffraction,scanning electron microscopy,transmission electron microscopy and UV-vis to study the properties of rare earth conversion phosphors.The results show that the size of rare earth upconversion luminescence powder Y₂O₃:Er³⁺ is between 0.1?m-5?m and it has strong absorption,in the infrared region.Under the 980nm laser,there are two strong emission bands between 535?570nm and 650?685nm,and these two wavelengths just coincide with the absorption range of dye N719.?2?P25 joined with different quality of rare earth conversion luminescent powder have?been made of adhesive paste,then we coated this paste on FTO conducting glass by doctor blade coating to prepare with rare earth luminescent powder doped P25 photoanode in dye-sensitized solar cells.We used a variety of testing methods,such as X-ray diffraction,scanning electron microscope?SEM?,transmission electron microscopy and UV-vis spectroscopy to characterize the photoanode properties.The research results show that when the content of rare earth is 4%,the photoelectric conversion efficiency of the photoanode is the highest,which is 7.8%,which is improved by 43.6%than that of the pure P25.?3?TiO₂ nanotube array films were prepared by anodic oxidation method.The double-layer composite photoanode of NTs/P25 has been prepared.Then we studied the impact of different length of battery efficiency.Then the viscous slurry of flower-like rare earth upconversion luminescence power has been prepared.A layer of up conversion phosphor paste was scraped on the surface of the nanotube photoanode.We used various kinds of testing methods,such as X-ray diffraction,scanning electron microscope,transmission electron microscope,ultraviolet-visible absorption spectrometer,and electrochemical workstation to characterize the properties of the anode.The results show that when the thickness of the TiO₂ nanotube film is 20.72 ?m,the photoelectric conversion efficiency of the nanotube film is the highest,which is 6.54%,Jsc is 17.81mA·cm-2,Voc is 0.66V,FF is 0.61.The photoelectric conversion efficiency is improved by 20.2%compared with the same P25 photo anode with the same thickness.The photoelectric conversion efficiency of the composite rare earth up conversion luminescent material NTs is 7.25%,the short circuit current density is 15.38 mA·cm-2,the open circuit voltage is 0.77V,and the filling factor is 0.61.