Preparation And Performance Study Of The Perovskite-Based Solid Solar Cells

The development of photovoltaic devices has been one of the effective ways to ease the energy crisis.Hybrid inorganic-organic perovskite based solar cells have been under an active investigation in recent days.Exploring a suitable technique to prepare stable,large-scale perovskite films and devices with higher stability is an important issue in the present.In addition,developing cost-effective hole-transport materials?HTMs?with simple fabrication,high hole mobility is significant for solid solar cells.From this view,our work were carried out mainly from the following two aspects.Firstly,we fabricated CH₃NH₃PbI3 layer in mesoscopic TiO₂ films via the electrodeposition method.In the preparation,PbO is first electrochemically deposited on the Ti O₂ film,then in situ transformed to PbI₂ by exposure to I₂.Finally the CH₃NH₃PbI₃ is synthesized by reaction with CH₃NH₃ I.We found that the PbO was well deposited in the pores of the TiO₂ film as well as on its surface.The coverage of PbI₂ on the TiO₂ film could be modulated by varing the electrodeposition time of the PbO.And the in-situ perovskite films with excellcent photoelectric property were obtained by the electrodeposition,achieving devices with an efficiency of 12.5 % and higher reproducibilty.Secondly,we synthesized two two-dimentional?2D?copper?2+?organic-based layered perovskites: P1,?p-F-C₆H₅C₂H₄-NH₃?2-CuBr4 and P2,?CH₃?CH₂?₃NH₃?₂-CuBr4.They were employed as HTMs for N719-sensitized solid-state DSCs for the first time.The precursor solutions for P1,P2 were made by mixing CuBr2 and the corresponding ammonium bromide at a molar ratio of 1:2 in ethanol.Two films were prepared,one from as-prepared P1 and P2,another directly from their precursor solutions.We found the two films had the same composition and structure,indicating the films of P1,P2 could be prepared directly from their precursor solutions.Besides,Li-TFSI and TBP were used as additives in P1,P2,causing a clear improvement in the performance of devices.The electrochemical impedance spectroscopy?EIS?were performed for devices with and without additives.The results showed that the hole conductivity of P1,P2 and charge transfer ability at the dyed TiO₂/HTM could be improved by the employment of Li-TFSI and TBP.After addition of Li-TFSI and TBP,devices for P1,P2 exhibited 0.50%,0.56% of PCE,respectively.