Performance Characterization Of Novel Thin-film Solar Cell Devices

In order to solve the problem of insufficient reserves of traditional fossil energy and environmental pollution,clean solar energy is continuously developed by human beings as a renewable energy.A typical representative of Dye sensitized solar cell（DSSCs）and perovskite solar cells（PSCs）as the third generation of new thin-film solar cells are widely attention and research,Because of its high Photoelectric conversion efficiency（PCE）,rich production material resources,convenient manufacturing process,flexible volume,it is expected to meet the needs of human development and life.Traditional DSSCs are assembled into battery devices by packaging and processing liquid electrolyte materials,but they have some defects,such as volatile solvent in the electrolyte,leakage,degradation of dyes and corrosion of electrodes,which limit their commercial development.Today,the photoelectric conversion efficiency of PSCs has reached 25.7%,which is comparable to that of traditional silicon-based solar cells.While continuously improving device performance,researchers pay more attention to the stable performance of PSCs devices and the selection of environmentally friendly raw materials.In this paper,the application of quasi-solid gel electrolyte in DSSCs is studied to solve the deficiency of liquid electrolyte,and to improve the conductivity of electrolyte through the method of additive to improve the photovoltaic performance of the device.At the same time,the performance optimization of the new double perovskite Cs₂Ag Bi Br₆ cell device with additive as the modified interface layer was studied.The main research contents and conclusions are as follows:1.DSSCs cell devices were assembled by the gel electrolyte system constructed by using polyacrylonitrile（PAN）as gel agent,vinyl carbonate and propylene carbonate as plasticizer,binary salt sodium iodide（Na I）,1,2-dimethyl-3-propyl imidazole iodide（DMPII）and iodine to provide REDOX electron pairs.The sodium ion in Na I has a small ionic radius and is easily adsorbed on the surface of mesoporous Ti O₂.With the upward shift of the energy level at the edge of the conduction band,the distance between the LUMO energy level of the dye and the conduction band decreases,and the electron yield of the dye to the surface of mesoporous Ti O₂ increases,which helps to improve the short-circuit current density.Larger cations in DMPII,with lower lattice energy,dissociate more easily into free electrons and have higher electrical conductivity.Therefore,Na I and DMPII were cooperated with different molar ratios,and the device obtained when the molar ratio of Na I and DMPII was 1:1 had good conductivity and PCE reached 1.22%.The PCE is only 0.31%and 0.73%when the two iodized salt is used in the device alone.2.In order to improve the conductivity and charge carrier mobility of the gel electrolyte,cobalt ferrite nanoparticles were added as additives on the basis of Part（1）,which were added to the gel electrolyte at different mass ratios,and the conductivity of the gel electrolyte was significantly improved.When 3 wt%cobalt ferrite nanoparticles were added to the battery device,the PCE reached 2.24%.Better than other doping ratios 0 wt%（1.22%）,1 wt%（1.89%）,5 wt%（1.05%）.Compared with traditional liquid electrolytes,gel electrolytes are simpler to fabricate,lower cost,and do not require complex packaging process.3.In order to improve the carrier mobility of PSCs devices and the energy level matching between each layer structure,molybdenum oxide samples were prepared by hydrothermal method,and molybdenum oxide and PTAA in chlorobenzene solution were added to the perovskite absorption layer as interface modification layer to improve the photovoltaic performance of Cs₂Ag Bi Br₆ dual perovskite solar cells.The perovskite doped with molybdenum oxide has a smaller band gap width and a better energy level match with the perovskite layer,which improves the hole transmission and extraction.At the same time,the crystallinity and morphology of perovskite film are improved.The electrochemical test results show that the PCE of the perovskite cell device is 2.72%when molybdenum oxide and PTAA are used as additives together,which is significantly improved compared with the PTAA device alone（PCE=1.72%）and the blank control（PCE=1.27%）.