Study On Process Optimization,Material Modification And Trapping Effect Of CH₃NH₃PbI₃ Perovskite Solar Cells

Organic-inorganic halide perovskite materials,as the most potential absorber materials for the photovoltaic applications,have attracted growing attention due to its unique structure,simple synthesis process and photoelectric characteristics.The perovskite solar cells whose absorber is organic-inorganic halide perovskite materials have become a new type of photovoltaic devices with rapid development in recent years.In this paper,we selected the organic-inorganic hybrid perovskite material CH₃NH₃PbI₃ as the research object to study some key scientific problems,mainly related to:the process optimization of optical absorption layer material,the preparation and properties of Ag-doped CH₃NH₃PbI₃ materials and their devices,the textured perovskite film and photovoltaic devices fabricated based on trap-light design.The relevant mechanism has been deeply studied.The details of the study are as follows:?1?An improved antisolvent precipitation process for preparation of CH₃NH₃PbI₃ absorber and mesoporous perovskite solar cells were developed.The crystallization behavior was regulated by a green antisolvent-ethyl acetate to replace the commonly used nonpolar solvent chlorobenzene,toluene.The addition of methyl chloride into the precursor to promote the formation of intermediate products,which can control the crystallization process to form the high-quality CH3NH3PbI3 film.It was found that the grain size of CH₃NH₃PbI₃ film prepared after the annealing for 30minutes increased and the grain boundaries can be reduced.Meanwhile,the transmission and injection characteristics of the carriers can be enhanced,and the photoelectric conversion performance is greatly improved.?2?Ag-doped CH₃NH₃PbI₃ film and the solar cells were prepared in ambient atmosphere with the relative humidity of 30%-40%,and the energy conversion efficiency was similar to that of perovskite devices prepared in dry environment.Thus,the sensitivity of perovskite devices to preparation conditions was reduced.It is found that the doping belongs to p-type doping,which reduced the density of defect states of CH₃NH₃PbI₃ material and enhanced the charge transport capacity.The PCE of the devices was 14.26%,which was 20.1%higher than that of undoped photovoltaic devices.?3?From the point of view of optical design,the optical absorption of perovskite solar cells have been enhanced by using textured FTO substrates and embedded silver nanoparticles to induce the surface plasmon resonance.The light trapping strategy based on the above design balanced the restriction relationship between photon absorption and exciton capture in the device,which promoted the generation and collection of interface charges and improved the photoelectric performance of perovskite photovoltaic devices.Finally,we get perovskite photovoltaic devices with an efficiency of up to 15.25%,which is 28.1%higher than that of untreated cells.