Room Temperature Sputtering Tin Dioxide Film Applied In Perovskite Solar Cells

Due to the excellent light absorption properties and simple solution printability of perovskite material,the hybrid perovskite solar cell?PSC?has developed speedily and a certified PCE based on small area cell?<0.1 cm²?has reached 23%.There is also exclusive superiority for PSC in tandem solar cells,semitransparent solar cell and flexible devices.However,the difficulty in large area fabrication devices,especially in the industrialized and large-area preparation of the electron transport layer?ETL?is still an urgent problem to be solved.On account of its good stability,easy low temperature preparation and excellent performance,Tin dioxide?SnO2?has become an extremely promising electron transport layer material.In this thesis,we prepared SnO₂ ETL by magnetron sputtering for the first time and applied it to the flat structure PSC.The sputtering process of two different types of SnO2 targets was investigated in detail,including the Ar/O2 ratio during the sputtering,the thickness and post annealing of the sputtered SnO₂ film,and the PSC in small area and perovskite solar module were also fabricated.Then,we tried to explain the cause of the hysteresis of perovskite device by optimizing the sputtered SnO₂ film.The UV-Vis spectrophotometer?UV-Vis?,Scanning electron microscope?SEM?,X-ray diffraction?XRD?,Atomic force microscope?AFM?,X-ray fluorescence spectrometer?XRF?,electrochemical workstation,J-V scanning and other methods were used to test the related results,and some results were obtained.Details as follows:1.We attempted to prepared SnO₂ film at room temperature?RT?by sputtering a conductive SnO₂ target with direct-current?DC?supply and applied it to regular architectures?n-i-p?PSC.by adjusting the Ar/O₂ ratio during the sputtering and optimizing the anneal temperature of sputtered SnO₂ film,a best efficiency of 15.8%was obtained in small area PSC.2.We prepared SnO₂ film at RT by sputtering a non-conductive SnO₂ target with radio frequency?RF?supply.By adjusting the Ar/O₂ ratio,we found that an appropriate amount of Oxygen partial pressure can sputter a dense and low defect density SnO₂film.By further optimizing the thickness of the sputtered SnO₂ film,a champion efficiency of 18.20%was obtained on a small area regular architectures PSC.Moreover,the histogram of the statistic efficiency of small area PSC shows good repeatability,and the corresponding perovskite module has a maximum efficiency of 14.71%.3.We further optimized the post-annealing temperature of SnO₂ film prepared by sputtering a non-conducting target at RT,and found that the PSC based on SnO₂ film without annealing treatment show better efficiency.Then,by using the PCBM modified sputtered SnO₂ electron layer,it was found that PCBM can reduce the hysteresis of PSCs by accelerating carrier transport,but it also introduces new defects so that it cannot completely eliminate the hysteresis of the devise.By using KI modified SnO₂electron layer,and found that KI can completely eliminate the hysteresis of the device by accelerating carrier transport while reducing defects.Finally,we used the KI/PCBM double layer to modify sputtered SnO₂ electron layer,and found that KI can also eliminate the hysteresis of the device without contacting the perovskite film.