Efficient Preparation Of Perovskite Solar Cells And Doping Of Light Absorption Layer

Since in 2009,perovskite solar cells(PSCs)have attracted lots of attention in the field of optoelectronics.In just over 10 years,the photoelectric conversion efficiency(PCE)has climbed from the original 3.8%to 25.2%.The performance of the PSCs optical absorption layer is one of the main factors affecting its PCE.Among them,improving the preparation process of perovskite layer and the doping modification of optical absorption layer are effective methods to improve the performance of the device.The two-step method is used to prepare PSCs.In this paper,we improve the two-step method and realize the effective doping of single-walled carbon nanotubes(SWCNTs)in the light absorption layer to improve the performance of the device.The contents of the study are as follows:(1)The influence of perovskite layer thickness on PSCs performance was studied.The Pb I₂spin-coating speed during the preparation of perovskite layer by two-step method was changed to change the thickness of the perovskite optical absorption layer and the PCE.And the devices prepared at different speeds.The results show when the spin-coating speed of Pb I₂is 1500 r/min,the perovskite layer thickness achieved the maximum light absorption,and the corresponding PSCs device achieved the highest PCE.(2)The effect of annealing temperature on the properties of the optical absorption layer was studied.Changed the annealing temperature of perovskite films to prepare perovskite films and devices.The results showed that the precipitation of Pb I₂increases with the increase of annealing temperature and the crystallinity of perovskite layer reached the optimum and the devices of PCE reached the maximum at 150?.When the temperature rose to 250?,after 15 minutes,the perovskite film completely decomposed,leaving only the yellow Pb I₂.Therefore,the optimal annealing temperature of PSCs is 150?.(3)Two spin-coatings Pb I₂improved PSCs preparation process.Based on the traditional two-step method,this experiment carried out two spin-coatings Pb I₂and systematically studied the thickness of the film formed.The results showed that the Pb I₂film of the first spin coating will be partially dissolved when the second spin coating of Pb I₂by using the same solvent,so the thickness of the final film was not the sum of the film thickness Pb I₂.The rotation speed of Pb I₂in the first and second time were changed in the experiment,and the film thickness of Pb I₂and perovskite film were compared to obtain the law of the rotation speed of Pb I₂and perovskite films.(4)The addition of SWCNTs to the PSCs optical absorption layer effectively enhanced the PCE of PSCs.PSCs containing SWCNTs were prepared by doping the optical absorption layer of PSCs with SWCNTs in Pb I₂solution with no functional groups for the first time.The results showed that the incorporation of SWCNTs effectively penetrated the perovskite grain boundary and reduced carrier recombination in perovskite films.When the doping concentration of SWCNTs was0.025 mg/m L,the devices prepared were approximately 1.5%higher than the PCE without SWCNTs.Continuous testing of devices containing SWCNTs(time interval2s)showed a continuous increase in PCE due to the excellent electrical conductivity and storage electronic properties of SWCNTs(none of the devices without SWCNTs).It was proved that the doping of SWCNTs without any functional groups on the optical absorption layer of PSCs could effectively improve their PCE.