Preparation And Performance Study Of Inorganic CsPbI_3-xBr_x Perovskite Solar Cells

In recent decades,perovskite materials as photovoltaic materials gradually entered the attention of scientists.After 2012,perovskite materials were used as light absorbing materials in the form of solid film prepared by solution method,which opened a decade of rapid development of perovskite photovoltaic cell technology.At present,perovskite solar cells are already more efficient than silicon-based cells.It was found that cesium metal(Cs)atoms can be used to replace the organic molecule methylamine(MA)to synthesize cesium-based perovskite materials,and the thermal stability of cesium-based perovskites is greatly improved due to the introduction of cesium.All-inorganic perovskites are direct bandgap semiconductors that are very suitable for the preparation of series high-efficiency solar cells,but the black phase CsPbI3-xBrx with excellent photovoltaic performance will change to the yellow phase CsPbI3-xBrx with extremely poor photovoltaic performance under the action of water and oxygen.The power conversion efficienc and device stability of inorganic perovskite cells need to be further studied.So this thesis uses different passivation to prepare solar cells based on inorganic CsPbI3-xBrx perovskite and systematically studies the related properties.This thesis begins with the following four aspects:(1)Based on the FTO/PEDOT:PSS/CsPbI3-xBrx/PCBM/Al structure of inorganic perovskite solar cells.Preparation of inorganic perovskite active layer by introducing 2-(4-fluorophenyl)ethanamine hydroiodate(F-PEAI)into inorganic CsPbI3-xBrx perovskite precursor.By adjusting the amount of F-PEAI doped into the inorganic perovskite precursor,we found that the amount of F-PEAI has a significant effect on the performance of the device.When 20 μL F-PEAI solution is added to the perovskite precursor,the energy level of the perovskite layer and the functional layer is more matched,which helps to improve photovoltaic performance.20 μL F-PEAI solution-treated perovskite film is denser and the pinhole is significantly reduced and the power conversion efficiency of perovskite solar cells was increased to 11.18%.(2)Based on the FTO/TiO2/CsPbI3-xBrx/Spiro-OMeTAD/Ag structure of inorganic perovskite solar cells.By introducing phenylpropylamine bromide(PPABr)into inorganic CsPbI3-xBrx perovskite precursor to prepare perovskite solar cells.It was found that with the addition of PPABr,the perovskite film became denser and the pinholes were reduced,which significantly improved the performance of devices.The introduction of 2.5 mol%PPABr significantly increased the efficiency of perovskite cells to 13.14%and device stability over 150 hours is also improved.(3)LiF,an ionic chemical dopant,was studied to improve the defects of the perovskite layer and prepare efficient and stable perovskite photovoltaic cells.LiF as a dopant can control grain growth and achieve larger grain sizes.The crystal structure,morphology,and electrochemical impedance spectroscopy(EIS)of LiFdoped all-inorganic CsPbI3 perovskite films were studied to determine the relationship between film quality and device performance.Doping of 2 mol%LiF greatly improves the performance of the device,eliminates the hysteresis effect of the device,and increases the power conversion efficiency of the device to a maximum of 17.02%.In addition,device stability is greatly enhanced.(4)RbF,a metal fluoride additive,was studied for the preparation of photovoltaic cells with high efficiency,low hysteresis,and stability.As an inorganic metal fluoride additive,RbF can control and affect the crystal growth kinetic process,so as to obtain a well-crystallized perovskite film.By studying the properties of RbF-doped fully inorganic CsPbI3 perovskite films and the preparation of corresponding perovskite solar cells.The conclusion is that 0.03 mol%RbF doping has the best effect,the device hysteresis factor of 0.03 mol%RbF doping is reduced to 0.003,and the power conversion efficiency of perovskite solar cells can reach up to 17.21%.Moreover,the stability of the device prepared by 0.03 mol%RbF doping was also significantly improved.