Research On Perovskite Crystal Film Defect Passivation And High-Efficiency Stable Perovskite Solar Cells

At present,the photoelectric conversion efficiency of perovskite solar cell（PSC）has exceeded 25%.However,the stability of PSC is still a serious problem,has not been resolved.Defects in perovskite layer surface and interior are the main factors that lead to instability.This thesis through passivation perovskite material defects to improves the efficiency and stability of PSCs.（1）Combination with methylamine gas post-treatment and neopentylamine hydrochloride（NPACl）passivation,the defects in bulk MAPb Br₃ perovskite perovskite/ETL and perovskite/HTL been passivated.The PSC obtained an ultra-high open circuit voltage of 1.650 V,PCE is 10.33%.Besides,under 60°C and 1 sun irradiation,after 1100 h,the PSC device retains 91.3%of its initial efficiency.（2）Two thiadiazole derivatives（TDZT and TDZDT）were added into a perovskite precursor to modulate MAPb I₃ perovskite crystal growth.Thiadiazole derivatives can help form large size of the MAPb I₃ crystals and can reduce defect at the grain boundaries.As a result,the device with TDZDT obtained a PCE of 19.04%.The unsealed devices retained 91.2%of their initial PCE after 1200 h in 65±5%relative humidity at room temperature.（3）Here,a judiciously engineered passivator,4-tert-butyl-benzylammonium iodide（tBBAI）,was introduced.It is found that simple surface treatment with tBBAI can significantly passivate perovskite surface defect and retard the nonradiative charge carrier recombination.This boosts the PCE of the PSC from 21.2%to 23.5%.As a result,the PSC show excellent operational stability retaining over 95%of their initial PCE after 500 h full-sun illumination under maximum-power-point tracking under continuous simulated solar irradiation.（4）To partially offset the hydrophilicity caused by Li-TFSI and t BP in the spiro-OMe TAD hole transport layer,a small amount of 4-（trifluoromethyl）pyridine（TFP）was added to the spiro-OMe TAD solution.To further increase the hydrophobicity of the perovskite surface,4-trifluoromethyl-benzylammonium iodide（TFMBAI）was designed and used as a passivator.The efficiency of device based on perovskite/TFMBAI/TFP boosting to 23.9%and suppressed hysteresis.The efficiency of the device retaining over 96%of their initial efficiency after 500 h,under simulated full-sun irradiation,and 97%of their initial efficiency after 1100 h exposure under ambient condition to a relative humidity of 60-70%.（5）Here,we design a novel dopant free HTM,named Me OTTVT.The PCE of champion PSC based on Me OTTVT up to 21.30%,which is considered as one of the best-performing PSC employing a dopant additive-free small molecule HTM.Due to Me OTTVT obtain a more hydrophobic surface and high glass-transition temperature,PSCs based on an Me OTTVT dopant additive-free HTL exhibit outstanding stability against moisture,1 sun illumination,and thermal condition.