Study On The Performance Of Perovskite Solar Cells Based On Ce-doped TiO₂

With the rapid rise of new energy sources,the development and utilization of solar cells has become a hot issue of concern.Perovskite solar cells stand out because of their excellent photoelectric conversion efficiency,which has also attracted the interest of many researchers.Through the gradual improvement of the preparation process,the photoelectric conversion efficiency of perovskite solar cells has increased to 25.2%.Low production cost and simple preparation process make perovskite solar cells one of the most promising members of solar cells.Carrier migration and recombination behavior at the interface between perovskite solar cells directly affect their performance.These behaviors depend not only on the quality of the perovskite film,but also on the size of the interface barrier.Most perovskite solar cells use TiO₂ with good light transmission and stable performance as the electron transport layer material.However,there are many defects on the surface of the TiO₂ film,and carrier recombination is easy to occur,which affects the photoelectric conversion efficiency of the perovskite solar cell.Therefore,a series of experiments on the TiO₂ electron transport layer are carried out to find a method to improve the efficiency of perovskite solar cells.In this paper,the TiO₂electron transport layer was prepared by chemical bath deposition method.In order to improve the battery performance,we did the following work:?1?The TiO₂film was prepared on FTO by chemical bath deposition method,and the thickness of film was controlled by time.TiO₂ films were prepared with water bath lengths of 20min,40min,60min,80min and 100min respectively.Perovskite layer,hole transport layer and Ag electrode layer are deposited on compact TiO₂ layer by spin coating to prepare planar structure perovskite solar cells.The thickness of TiO₂ electron transport layer was characterized by scanning electron microscope,and through the photoelectric test under simulated sunlight to explore the effect of different thickness of TiO₂ on the photovoltaic performance of perovskite solar cells.?2?When the perovskite film is prepared by the two-step spin coating method,PbI₂ spin coating needs annealing treatment,and then MAI spin coating.XRD test found that the perovskite film contains more PbI₂ residue.In order to prepare high-quality perovskite thin films,spin-coat MAI immediately after spin coating PbI₂,then annealing.The perovskite thin films based on annealed and unannealed PbI₂ were characterized.The results showed that the surface of the perovskite thin films based on unannealed PbI₂ was smooth and PbI₂ residue was significantly reduced.The photoelectric performance of perovskite solar cells based on annealed and unannealed PbI₂ was explored through photoelectric testing,in which the performance of devices based on unannealed PbI₂ was higher.?3?Ce element is doped with TiO₂ as the electron transport layer of the device.Different molar amounts of CeCl₃ were added to the TiCl₄ aqueous solution to prepare a precursor solution having a concentration of 0 M,0.003 M,0.006 M,0.009 M,and 0.012 M,respectively.The Ce-doped TiO₂ was deposited on the FTO by bath method and annealed at 500°C for 30 min to prepare a compact TiO₂ layer with different doping concentrations.X-ray diffraction and X-ray photoelectron spectroscopy confirmed the successful doping of Ce element into TiO₂.The perovskite solar cells were prepared by the above method.Through the photoelectric test,the J-V curve of Ce-doped TiO₂ perovskite solar cells was obtained,and the effect of different concentrations of Ce doping on the performance of perovskite solar cells was studied.Through experiments,it was found that the device efficiency of 0.009M Ce-TiO₂ is higher,and the efficiency of the champion device reaches 16.18%.