Study On Sulfide Nano-material Prepared By Solution Chemistry Methods Applying On Solar Cells

With the increasingly serious energy problems in the world,solar cells have received extensive attention.Looking for a green,high-efficiency,low-cost solar cells has became a research hot spot.Polymer solar cells and perovskite solar cells have developed dramatically in recent years.Polymer solar cells are simple in preparation process,low in cost,and can be used for roll-to-roll large-area preparation;the high efficiency of perovskite cell and the low-cost make it one of the most valuable solar cells.Although the above two types of solar cells are developing rapidly,they all have shortcomings that impede their way to commercialization:the problems of low carrier mobility and poor battery stability of polymer solar cells need to be solved;perovskite materials have problems of instability,which cannot be ignored.Metal sulfides have been widely used in the above two solar cells due to their proper energy band structure,high dielectric constant and excellent electron transport performance.Commonly used methods for preparing metal sulfide thin films include vacuum evaporation method,near-space sublimation method,molecular beam epitaxy method,etc.,but these methods have higher requirements on equipment or experimental conditions.Therefore,the problem faced by sulfide materials now is to find a low-cost,environmental-friendly and simple preparation method.In this paper,two solution chemistry methods,thermal decomposition of xanthic acid complex method and low temperature solution method,are used.Compared with the commonly used preparation methods,the method of thermal decomposition of xanthic acid complex is low in cost,facile,suitable for large area industrial preparation and can obtain a smaller size and a denser metal sulfide film.Low temperature solution method for preparing nano metal sulfide is low cost and easy to operate.In this paper,sulfide nanomaterials were mainly prepared by solution chemistry and used in the research of solar cells,and their properties were characterized and analyzed.At first,cadmium xanthate complex was synthesized as a precursor of cadmium sulfide thin film,whose morphology,structure,optical properties and physical and chemical properties were tested.Then,the cadmium sulfide film prepared by thermal decomposition of cadmium xanthate complex was used to modify the dense TiO2 layer in mesoporous perovskite solar cells,whose structure is FTO/c-TiO2/CdS/mp-TiO2/MAPbI3/Spiro-OMe TAD/Au.Then the experimental conditions were optimized,the factors that affect the performance of the device were explored and analyzed,the highest photoelectric conversion efficiency of 11.26%was finally obtained.In the comparative experiment,CdS was used as the only dense layer film,and the device structure was composed of FTO/CdS/mp-TiO2/MAPbI3/Spiro-OMe TAD/Au,and the photoelectric conversion efficiency of 12.83%was finally obtained.Secondly,the precursor for preparing Sb2S3 thin film:antimony xanthate complex was obtained,whose structure,optical properties and physical and chemical properties were tested.CdS or Sb2S3 nanoparticles were prepared by thermal decomposition of xanthogen acid complex,and were mixed with poly 3-hexylthiophene:[6,6]-phenyl-C61-n-butyric acid methyl ester(P3HT:PC61BM)as active layer.This method effectively achieved the effective combination of sulfide nanomaterials and polymers active layer,removed the need of surfactants for the sulfide nanomaterials and co-solvents which have been used for better mix of nano metal sulfide materials and polymers.By optimizing the device structure and related conditions,device structure of ITO/CdS/P3HT:PC61BM:x wt.%CdS/MoO3/Ag and ITO/CdS/P3HT:PC61BM:x wt.%Sb2S3/MOO3/Ag were prepared.The main performance and parameters of the devices were analyzed,and the best photoelectric conversion efficiency of 2.91%and 2.92%are obtained respectively.Finally,bismuth sulfide nanocrystal thin films with different morphology were prepared by a low temperature solution method,in this process,aqueous solution of thiourea and bismuth nitrate were used as the precursor materials.The obtained bismuth sulfide film was characterized,and the influence of experimental conditions on the properties of the material was studied.A cation conversion reaction was attempted on the obtained bismuth sulfide nano film in order to get Bi2S3@Cu2S shell-core structure,the converted films were tested and analyzed.