Study On Charge Transport Layer And Its Interface Of Perovskite Solar Cell

In recent years,perovskite solar cells have shown the rapid development in photovoltaic technologies.Until now,the certified power conversion efficiency of traditional perovskite solar cells has already exceeded 25%.In essence,it is derived from the structure of the solar cell device,the optimization design of the materials and the improvement of the film quality.In this paper,the experimental system is an inverted structure CH₃NH₃PbI₃ perovskite solar cell.The preparation process was systematically optimized.The basic preparation process,the application of new materials in the hole transport layer,and the passivation of the perovskite film on the device were explored.The main results are shown below:1.Study on basic technology of traditional inverted structure perovskite solar cells.The morphology and photoelectric properties of PTAA hole transport layer doped with F4-TCNQ and the effect on the ratio of PbI₂:MAI in the perovskite precursor solution were investigated.The result showed that F4-TCNQ not only helped improving the hole-transporting capacity of PTAA,which reduced the series resistance of solar cells,and also improved the thin film morphology of PTAA and perovskite,which helpd to improve the parallel resistance of solar cells,and ultimately reflected the increased photoelectric conversion efficiency of the device.At the same time,the effect of the addition time and amount of sec-butyl alcohol as an anti-solvent in the one-step solution spin coating method on the performance of battery devices was studied in this paper.It was found that only a proper amount of sec-butanol was added as an anti-solvent at an appropriate time to obtain a battery device with superior performance.The effect of the spin coating speed of the electron transport layer PCBM on the device performance was studied in this paper.It was found that the device with the electron transport layer obtained by spin coating at a lower speed had the best performance,and finally a device with a photoelectric conversion efficiency of 15.10%was obtained.This is mainly because the film-forming properties of PCBM are average,and a larger thickness is required to ensure film coverage.2.Study on application of small molecule HAT-CN materials in PTAA hole transport layer.The process parameters of adding HAT-CN as a doped material in the hole transport layer and the vapor deposited HAT-CN as a buffer layer between ITO and the hole transport layer were studied respectively.The result showed that the material was only suitable for a small proportion doping.If the doping ratio is too high,the defects in the hole transport layer will increase,which will affect the hole transport ability of the hole transport layer.And it was found that the evaporated HAT-CN layer should not be too thick,the thicker HAT-CN layer hindered the transport and collection of holes.In the end,devices based on HAT-CN materials achieved a photoelectric conversion efficiency of 16.25%and 16.03%,respectively.3.The defect passivation process of D4TBP material in CH₃NH₃PbI₃ film.The configuration method of D4TBP solution was studied in this paper,and it was found that the passivation effect of D4TBP solution dissolved in isopropyl alcohol was better;The effects of the D4TBP passivation layer obtained by different spin coating speeds on the device performance were compared;Finally,the effect of annealing process on the defects of perovskite thin film passivated by D4TBP was studied.The research result showed that the performance parameters of the non-annealed device were higher than those of the annealed device and the reference device,and the photoelectric conversion efficiency could reach18.9%,while the performance of the annealed device was significantly lower than the reference device,It showed that the annealing process had a significant effect on the battery performance.The reason may be that annealing causes D4TBP to deteriorate or change the chemical effect of D4TBP/perovskite interface.