Organic-inorganic Halide Perovskite Film Morphology Control And Optimization Of Solar Cell Devices

As a new type of photoelectric conversion device,perovskite solar cell has a short history but has become a hot spot for laboratory research.Due to the toxicity of lead,scientists have tried to use tin to replace lead to prepare lead-free perovskite solar cells.Although Sn-based perovskite exhibits better optical properties than Pb-based perovskite,due to the instability of divalent tin,tin-based perovskite solar cells are still unable to compete with lead-based perovskite in terms of cell efficiency and stability.Mine solar cells are comparable.This article attempts to control the morphology of the perovskite film through component engineering and solvent engineering to improve the efficiency of the device.The specific content of this article is as follows:(1)Improve the performance of PSC by adding methanol into the FASnI₃ precursor solution.We dissolve methanol with different doping volume ratios in the perovskite precursor solution,and rinse the ITO surface with ethyl ether during the spin coating process.The measurement results show that compared to the reference device,the optical performance of the methanol-doped perovskite device has been significantly improved.Since methanol is slightly soluble in DMSO,an appropriate amount of methanol can extract excess DMSO to accelerate the formation of the perovskite films and Optimize the effect of crystallization.The proper amount of methanol is mixed to obtain a more excellent device film morphology:larger grain size,lower film roughness and relatively reduced film defects.The loss in the carrier transport process is also greatly reduced with the improvement of the film morphology,which is conducive to enhancing the short-circuit current of the perovskite and ultimately improving the PCE of the entire device.Finally,the increase of Jsc in the measured J-V curve of the device also very well confirmed our inference.Among them,when the doping ratio is 5vol%,the perovskite film has the best crystallinity,and the film quality is the most excellent.Its PCE is increased from 2.13%of the standard part to 2.80%.(2)The method of doping DMA(mixed cations)in the perovskite solution by FASnI₃ changes the crystal structure of the perovskite to achieve the effect of improving the optical performance of PSCs.The experimental test results show that the incorporation of DMA ions successfully changed the crystal orientation of the perovskite..At the same time,the surface of the prepared film was flatter and the crystal grains became larger.This change also played a good role in increasing the short-circuit current of the device.The change of the ultraviolet absorption spectrum shows that the appropriate amount of DMAI doping not only increases the light absorption capacity of the film,but also has a certain impact on the band gap of the perovskite.The change of the band gap can affect the Voc of the battery..Among them,when the DMAI doping ratio is 0.12(the perovskite molecular formula is DMA_0.12FA_0.88SnI₃),the device exhibits the best optical performance.At this time,V_OC is0.47 V,and the J_SC is 16.71 m A/cm²,FF increased to 69.9%,and its PCE is increased from 3.01%of the standard part to 5.15%.(3)Improve the optical performance of the device by adding DIO to the anti-solvent.Dissolve DIO in the anti-solvent chlorobenzene at different concentrations,and rinse with chlorobenzene when spin-coating the perovskite solution.The experimental results confirm that the doping of DIO makes the device produce more excellent optical performance.The crystallinity of the perovskite in the XRD diffraction pattern has also been significantly improved,and the SEM can also clearly see that the morphology of the film has been improved,the crystal grains have increased,and the grain boundaries have decreased.The ultraviolet absorption visible spectrum also well proves the increase in the absorption intensity of the perovskite film in the visible light range.When the volume ratio of DIO doping is 2%,the optical performance of the device is optimal,and the PCE is increased from 3.2%of the reference part to 4.1%.