Studies On Perovskite Solar Cells Based On Ordered SnO₂ Mesoporous Layer

Perovskite solar cells have made great progress since Professor Miyasaka proposed them in 2009.Its photoelectric conversion efficiency（PCE）has many technological breakthroughs,which has increased rapidly from 3.8%to 25.7%.In recent years,hybrid lead perovskite solar cells（PSCs）have attracted great attention because of their high absorption coefficient,long carrier diffusion length,and adjustable bandgap.Although the PCE has been significantly improved,there is still a long way to go from its Shockley-Queisser limit,and factors such as hysteresis and stability restrict its development.As we all know,there are mainly the following directions for the improvement of PSCs:one is to study new perovskite material components;the other is to optimize the contact surface between each layer;the third is to construct mesoporous structure.Among them,the construction of mesoporous（mp-）PSC can increase the contact area between the absorb layer and the electron transport layer（ETL）,and effectively improve the interface charge transport.However,the mesoporous structures constructed by using nanoparticles traditional methods are mostly disordered structures,in which the narrow pores and disordered contact mode will affect the growth of perovskite grains and the directional transport of carriers,limiting the performance improvement of devices to a certain extent.The ordered mp-structure can effectively enhance the optical coupling process,improve the light absorption of perovskite,and optimize the interfacial charge transport.Therefore,we study the ordered structures in PSCs is of great significance to improve the light absorption efficiency of perovskite,the PCE and stability of PSCs.The work of this paper is mainly reflected in the following aspects:（1）We ameliorated the reassembly method and developed the corresponding preparation device.By using this method to produce high-quality monolayer polystyrene microsphere films,we use this as a template to produce ordered SnO₂films by spin-coating osmosis method.The optimal parameters of experimental variables were obtained,and the 2D IO SnO₂（SIO）films prepared were orderly arranged,dense and continuous,which could be used as mesoporous scaffolds for PSCs.（2）The influence mechanism of SIO as mp-ETL on the performance of PSCs was investigated.The morphology of the film and interfacial charge transport dynamics of device prove that the ordered mp-ETL and the nested perovskite light absorption layer increase the light absorption of the perovskite layer,improve the electrical properties of the contact surface and enhance the stability of PSC.The best PCE of device based on SIO-5 reaches 20.03%.The research results show that the ordered SIO mesoporous layer can effectively optimize various parameters of PSCs,improve the light absorption and stability.And this way is a simple and efficient method to prepare high-performance and stable PSCs.