Development And Optimization Of Key Materials For Planar Heterojunction Perovskite Solar Cells

In order to alleviate the energy crisis,it is imperative to develop new renewable energy sources which are environment-friendly and renewable.Solar energy is considered as the important energy supply to mankind development in the future.The development of low-cost,high efficiency of new generation solar cells has become a researching hot spot in recent years.Perovskite solar cells?PSCs?have been attracting enormous interest owing to their excellent advantages,including low cost,easy preparation,and high efficiency.However,the fabrication of high-quality perovskite thin films and high-efficiency devices is still a challenge.Therefore,we mainly does the following work in this paper:?1?According to solvent engineering,we design a ternary mixed-solvent for the growth of high-quality perovskite films.The crystallization rate of perovskite was slowed down by adding N-methylpyrrolidone?NMP?,a solvent with coordination function to lead iodide?PbI₂?,in perovskite precursor solution.When the optimum volume ratio of NMP to dimethylsulfoxide?DMSO?was reached,the power conversion efficiency?PCE?reached as high as 19.61%.?2?Based on green solvent engineering,high quality perovskite thin films and devices were prepared.A perovskite thin film was prepared by using non-toxic green solvent ethyl acetate?EA?as the solvent for preparing the hole transport layer and using EA instead of CB as an anti-solvent to induce rapid nucleation of the crystal grains.Based on this solvent engineering,the effects of different precursors of perovskite precursors on the film quality and device performance were explored and the PCE of the champion device reached 19.23%.?3?High efficiency and less-hysteresis planar perovskite solar cells were prepared by interface engineering.CdS/TiO₂ electron transport layer was prepared by spin-coating cadmium sulfide?CdS?quantum dots on a TiO₂/FTO substrate and exploring the influence of different blocking layers on the optoelectronic properties and device stability.By optimizing the concentration of CdS quantum dots,a device with planar structure with weak hysteresis was fabricated,which displayed a 18.89%PCE for the reverse scan and 18.30%PCE for forward scan.Meanwhile,the efficiency of the device remained unchanged at 84%after 20 days.