The Fabrication Of Efficient And Stable Perovskite Solar Cells By Modification Of Monoamine Zinc Porphyrin

Organic-inorganic hybrid perovskite material has become one of the most promising light absorbers for next-generation solar cells due to their unique advantages,including high absorption coefficient,high carrier mobility,long carrier diffusion length,tunable band gap and so on.Over the past decade,the photoelectric conversion efficiency of perovskite solar cells（PSCs）has increased rapidly from 3.8%to over 25%.More excitingly,sufficient raw materials and simple preparation processes endow PSCs with huge commercial potential.However,the long-term stability of PSCs under operating conditions is still the primary problem limiting their industrialization.In addition,it is the other challenge that how to reduce the efficiency loss when expanding the device area.In view of the above problems,this paper is mainly focus on modifying perovskite films by monoamine zinc porphyrin complex to adjust the quality and passivate the defects of perovskite films,thereby significantly improving the performance and stability of PSCs.Firstly,the structure and property of perovskite materials,the types and working principle of PSCs,and the development process of PSCs are briefly introduced.Then,a brief summary of the current problems and solutions of PSCs is given.Aiming at the main problems of PSCs,the research significance and contents of this paper are put forward to solve current problems.In order to passivate the defects at surface and grain boundaries of perovskite,we designed and synthesized monoamine zinc porphyrin（Zn P）complex,which was used to modify perovskite films as additive.The-NH₂ in the Zn P complex can react with perovskite in situ and bind to the surface and grain boundaries of the perovskite in the form of Zn P-H⁺.The research results showed that the modification of Zn P can regulate the growth of perovskite crystals,inhibit ions migration,achieve ion immobilization,and effectively reduce crystal defects.The performance and stability of PSCs based on Zn P-modified perovskite films have been significantly improved.Based on these,we fabricated large-area PSCs with a best efficiency of up to 19.01%by blade coating,providing a new strategy for the preparation of large-area PSCs.In order to explore the passivation mechanism,we designed and implemented four groups of control experiments to study the function of each group in Zn P molecule.The research results showed that the-NH₂ group in the Zn P complex can react with perovskite in situ and bind to the surface and grain boundaries of the perovskite in the form of Zn P-H⁺,effectively realizing ions immobilization.Porphyrin group can play a role of surfactant-like agents to regulate the crystallization process of perovskite thin films,thereby preparing uniformly high-quality perovskite films.Additionally,porphyrin group can also inhibit ions escape,effectively realizing ions encapsulation.The synergistic effect of each functional group of Zn P improved the performance and stability of PSCs,providing a new idea for the passivation of defects.We further modified the perovskite films using Zn P by surface modification through the coordination of-NH₂ and adjacent Zn²⁺to form coordination polymer.The results showed that Zn P molecules can self-assemble into one-dimensional"zig-zag"coordination polymer（Zn P-polymer）,which is uniformly deposited on the surface of perovskite thin films.Zn P-polymer promoted the interfacial charge transfer efficiently,thereby improving the champion efficiency of large-area PSCs.More importantly,the stability of PSCs based on Zn P-polymer surface modification was further improved significantly.