Research On Porous Stannic Oxide Perovskite Solar Cells And Novel Tin Monosuifide Hybrid Solar Cells

As solar energy is the inexhaustible renewable energy source,converting solar light energy into electric energy that can be used for human development has always been a key research area for scientists.Perovskite solar cells have attracted much attention because of their low preparation cost and less consumption of raw materials.At present,perovskite solar cells have achieved more than 25%conversion efficiency,but their stability is poor,so it is difficult to realize industrial production.SnS has also been proved to be a promising candidate for solar cells due to the abundance of tin and sulfur in the earth’s wall shells,sufficient global supply to meet photovoltaic material requirements,and low energy requirements for upstream processing of tin and sulfur compared to Cd Te or Cu（In,Ga）（S,Se）₂（CIGS）,low toxicity,no heavy metals,and has great potential to become photovoltaic application materials.However,the multivalency of tin and the complexity of Sn-S phase diagram lead to poor performance of SnS devices.Based on above background,the instability of perovskite cells and the deficiency of new SnS hybrid solar cells are need to be improved.In this paper,the porous SnO₂film was used as electron transport layer of perovskite cell,and the SnS film was used as absorbent layer of hybrid solar cell.The preparation and microstructure of porous SnO₂film and SnS film were studied,and the corresponding thin film solar cell devices were prepared.The contents and main conclusions of the thesis are as follows:（1）A hydrothermal reaction method for the preparation of sulfite films under 180℃was proposed,after 500℃calcination,stable and solid porous SnO₂films were formed.Compared with traditional porous Ti O₂films,porous SnO₂films have many advantages,such as simple preparation process,high electron mobility and better stability in UV region.The effect of different tin ion concentrations on the film formation in the hydrothermal reaction was studied.From the results of characterizations,we found that the porous SnO₂films prepared with the tin ion concentration of 2.4 mmol/L have the best morphology.The preparation method proposed in this paper lays a foundation for the application of porous SnO₂to replace porous Ti O₂in solar cells.（2）The as-prepared porous SnO₂film was used as perovskite solar electron transport layer to fabricate devices with structure of FTO/p-SnO₂/perovskite/spiro-o Me TAD/Ag.The effects of different tin ion concentration films on cell performance were counted.The optimized perovskite device achieved more than 7%power conversion efficiency,and the short-circuit current density was 22.62 m A/cm².Porous SnO₂structure is beneficial to improve the electron transport area,obviously weaken the hysteresis phenomenon of perovskite cells and improve the stability of the cells.（3）Sn_xS_ycompound films with different orientations were prepared by thermal evaporation deposition,the effects of different substrate temperatures(T_sub=150℃,250℃,350℃)on the films were studied.The results of XRD showed that pure SnS films with stable orientation could be prepared under the substrate temperature of 250℃,and the reaction mechanism under different temperatures was analyzed.The SnS films were verified by characterization results to contain only SnS phase existed,this result avoid the influence of complex phase surface on solar cells.Application in solar cells were realized and photovoltaic devices with structure of FTO/Ti O₂/SnS/P3HT/Au were prepared,the devices achieved 1.47%solar energy conversion efficiency,which laid a theoretical and practical foundation for the application of SnS films in solar cells.