Research On The Preparation Method Of Tin Based Light Absorbing Layers In Perovskite Solar Cells

With the progress of human society,the increasing consumption of fossil energy has caused pollution to the ecological environment.Therefore,it is urgent to find renewable clean energy to alleviate the contradiction between man and nature.Solar energy attracts much attention because of its huge reserves,which promotes the rapid development of photovoltaic technology.As a new type of thin film solar cell,perovskite solar cell has developed rapidly because of its simple preparation process,low cost and high photoelectric conversion efficiency.In the past decade,perovskite solar cells have increased the photoelectric conversion efficiency from the initial 3.8%to 25.7%.It can be seen that perovskite solar cells have broad development prospects,which can fully alleviate the problems of energy shortage and environmental pollution.However,nowadays,the light-absorbing layer of high-efficiency perovskite solar cells mostly use materials containing metallic lead.However,the toxicity of lead is harmful to the environment and organisms,which hinders its large-scale production and commercialization.Therefore,using other non-toxic or less toxic elements instead of lead is the most promising way to solve this problem.Sn²⁺has similar ionic size to Pb²⁺.Sn²⁺halide perovskite is considered to be the most promising material to replace Pb based perovskite because of its wide light absorption range,high light absorption coefficient and small exciton binding.Therefore,tin halide CH(NH₂)₂SnI₃(FASnI₃)was used as the light-absorbing material of perovskite solar cells to study the preparation method and composition of thin films.The specific work is as follows:1.FASnI₃ perovskite thin films were prepared by numerical control and manual antisolvent dripping methods and the tested PSCs with structures(ITO/PEDOT:PSS/Perovskite/C60/BCP/Ag).The results show that the repeatability of the device is higher in numerical control mode than that in manual mode.Furthermore,the effects of the height and speed of solvent drop on the morphology of thin films and device properties were studied.The results show that the solvent dripping height is 0.5cm away from substrates,and the dripping rate is 100?L/0.5s,the perovskite film quality and the light absorption performance is the best,and the corresponding device performance is optimal,reached 7.84%,Voc?Jsc and FF were 0.51 V?24.40 m A/cm²and 0.62,respectively,laying a foundation for subsequent research.2.We replace 15%of FAI in FASnI₃ with PEABr to prepare perovskite precursors and 3-fluorobenzide hydrochloride was added as additive.High-quality perovskite films with almost no holes,few interfacial defects and larger particle size were prepared,which improved the light absorption,charge transfer and collection properties of the perovskite absorbent layer.On the basis of the preparation of the structure of ITO/PEDOT:PSS/Perovskite/C60/BCP/Ag device,the device efficiency increased from 7.84%to 9.11%.