Investigation On The Photovoltaic Characteristics Of Carbon-based Perovskite Solar Cells Functionalized With Amino Ionic Liquid

Perovskite solar cells?PSCs?have been established as the most important new candidate for next generation photovoltaics,due to the excellent photoelectric property and facile fabrication process.Currently,the National Renewable Energy Laboratory?NREL?reports that the maximum photoelectric conversion efficiency is 23.7%.The excellent photoelectric conversion efficiency of PSCs comes from the excellent semiconductor properties of perovskite and the successive optimization of device structure.There are two key issues in solar cells,to improve the PCE and to reduce the manufacturing cost.Hence,much effort of PSCs have been focused on replacing the expensive materials,developing novel perovskite materials with high performance,stability and interfacial materials,optimizing morphology and crystallinity of perovskite layer.In this dissertation,we focused on improving the performance of PSCs via doping ionic liquid into perovskite film to improve the photoelectric properties of the PSCs.By using a novel two-dimensional perovskite material with hydrophobic ionic liquid was successfully fabricated and applied as photoactive element to construct a solar cell.Excellent photoelectric conversion efficiency and stability were demonstrated.Low-cost and hydrophobic carbon was used as the back electrode,further improving the stability of the device of the PSCs.The contents of this dissertation are summarized as following:?1?Hydrophobic ionic liquid 1-ethylaminehydrobromide-3-methylimidazolium hexafluorophosphate?ILPF₆?was used as dopant in carbon-based perovskite solar cells?C-PSCs?,which effectively improved the crystallization quality of perovskite crystals and the coverage of perovskite films on the substrate.After optimizing the parameters for PSCs preparation and dopping ILPF₆(0.03 mol L^-1)into the precursor solution for perovskite,the photoelectric conversion efficiency of the PSCs was enhanced to 13.01%,which is 29.08%higher than that of the CH₃NH₃PbI₃ based PSCs.When ILPF₆ is added,the grain boundary density of perovskite film decreases and the coverage increases,which can significantly promot the photogenerated carriers transfer.ILPF₆ ionic liquid with high hydrophobicity creates a moisture barrier and effectively improves the devices stability.?2?Using hydrophobic ionic liquid 1-ethylamine hydroiodic quinoline bis-trifluoromethane sulfonyl imide salt?[ILNTF₂]⁺I^-?,CH₃NH₃I and PbI₂ as raw materials,a novel two-dimensional perovskite,[ILNTF2]2?CH3NH3?9Pb10I31,was successfully prepared.Using[ILNTF₂]₂?CH₃NH₃?₉Pb₁₀I₃₁ perovskite as photoactive element,a carbon-electrode based solar cell was fabricated by one-step spinning coating.Under the optimized experimental conditions,the photoelectric conversion efficiency of 10.23%,short circuit current of 18.30 mA cm^-2,open circuit voltage of 0.946 V and filling factor of 59.09%were obtained.After being stored in dark state?RT 25 C RH 25%?for 7 weeks without encapsulation or other protection,the efficiency of the as-prepared PSCs remains 95%of its initial efficiency,exhibiting excellent stability.