Preparation And Performance Of Tin-based Perovskite Solar Cells

Perovskite Solar Cells（PSCs）have developed rapidly in recent years due to their excellent optical and electrical properties,and the Photoelectric Conversion Efficiency（PCE）up to 25.5%at now.But high-efficiency PSCs pollute the environment and endanger personal safety due to the use of lead,so it is important to find alternative non-toxic metals to replace lead.In Pb-free PSCs,tin-based PSCs are popular because of their advantages of non-toxicity,high extinction coefficient,narrow band gap and high exciton binding energy.However,it is difficult to control the nucleation rate and easy oxidation of the film during the preparation of the perovskite film,resulting in poor film morphology,which severely limits the improvement of device performance.In this paper,the effects of interface modification,component control and solvent engineering on the performance of perovskite films and devices are studied.The main contents of the work are as follows:（1）L-arginine is introduced into PEDOT:PSS to change the hygroabsorbability and strong acidity of PEDOT:PSS.Fabricate devices with the structure of ITO\PEDOT:PSS+L-Arginine\FASnI₃\C₆₀\BCP\Ag.Optimize the doping concentration of L-arginine.When the doping concentration of L-arginine is 1 mg/m L,PSCs obtains excellent performance.The PCE of the device is 4.14%,and the current density(J_sc)improvement is significant.After the storage of 400 hours in the glove box,the device efficiency still maintains 83%of the initial efficiency,which indicates an improved stability.（2）Introuduce PMAI into the FASnI₃ tin-based perovskite precursor solution,by adjusting the ratio of FA⁺and PMA⁺,the effect on the performance of perovskite films and devices is explored.Fabricate the PSC with a device structure of ITO\PEDOT:PSS\FA_1-XPMA_XSnI₃\C₆₀\BCP\Ag.The results show that the best device performance is obtained when X is 0.05,and the PCE of the device is 4.14%,significantly enhance the open circuit voltage(V_oc).In addition,the stability of the optimized device also improve.After the storage of 400 hours in the glove box,the device efficiency still maintains 83%of the initial efficiency,which indicates an improved stability.（3）Use FA_0.75MA_0.25SnI₃ as the perovskite absorption layer,add chiralα-hydroxy acid to the perovskite anti-solvent,and use R-（-）-MA and S-（+）-MA as reducing agents to inhibit Sn²⁺oxidation.Fabricate the PSC with a device structure of ITO\PEDOT:PSS\FA_0.75MA_0.25SnI₃\C₆₀\BCP\Ag,the anti-solvents are ether,ether doped with different concentrations of dextromandelic acid R-（-）-MA and ether doped with different concentrations of L-mandelic acid S-（+）-MA.The standard device PCE is 2.39%,and the best device efficiency can be obtained by optimizing the doping ratio,when the doping concentration is 0.03 mg/m L,the efficiency of the device is the highest,and the PCE of the device doped with R-（-）-MA is 3.67%,the PCE of the device doped with S-（+）-MA is 3.52%,the morphology of the perovskite film is obviously improved,the surface is uniform and dense,without pinholes,and the unit cell becomes larger.