Study On Tin Halide Perovskite Solar Cells Based On NiO_x Hole Transport Layer

With the rapid development of technology and economy,the continuous consumption of traditional fossil energy has aggravated the contradiction between men and nature,and the demand for clean and renewable energy is increasing.Solar energy is an ideal clean energy,which has a huge resource reserve.At present,photovoltaic technology that directly converts solar energy into electrical energy has attracted more and more attention.As a member of the new solar cell family,perovskite solar cells are considered to be a promising solution due to its power conversion efficiency(PCE)increased from the initial 3.8%to 25.5%in a few years,which shows the great potential of perovskite solar cells.However,perovskite solar cells also have shortcomings.Currently,high-efficiency perovskite solar cells use lead halide perovskite materials,but lead is harmful to the environment and organisms,which is not conducive to large-scale applications in the future.The tin halide perovskite is considered to be the most promising light-absorbing material in lead-free perovskite solar cells owing to low toxicity,suitable bandgap and high carrier mobility.In this paper,we are based on inorganic Ni O_x hole transport materials and HC(NH₂)₂SnI₃(FASnI₃)light-absorbing materials,the main contents are as follows:1.We synthesized high-quality non-stoichiometric Ni O_x nanoparticles by the solution precipitation method,prepared Ni O_x hole transport layers of different thicknesses by the dispersion spin coating method.Then we assembled the corresponding FASnI₃ solar cells to study the influence of the thickness of Ni O_x hole transport layer on the surface morphology of FASnI₃ thin films and performance of the devices.We found that the Ni O_x hole transport layer prepared by using the Ni O_x nanoparticle dispersion with a concentration of 20 mg m L^-1 shows the best performance,which have reached a PCE of 7.88%.This research laid the foundation for the further preparation of high-quality FASnI₃solar cells.2.In the view of the generally poor repeatability of FASnI₃ film,we added ionic liquid(1-butyl-3-methylimidazolium trifluoromethanesulfonate)into FASnI₃precursor solution to regulate the nucleation rate of FASnI₃film.In study,we found that doping with ionic liquid can improve the quality of FASnI₃ film,thereby increasing the short-circuit current of FASnI₃ devices,and the repeatability of the devices is significantly improved.However,ionic liquids can also intensify the recombination process of carriers and cause a drop in the open circuit voltage of the device.By optimizing the doping amount of ionic liquid,under the combined effect of short circuit current density(Jsc)and open circuit voltage(Voc),we have increased the average PCE of the devices from 6.81%to 7.82%,and the PCE of the best device is close to 9%.