| The power conversion efficiency of perovskite solar cells has been rapidly increased from 3.8%to 25.7%.Stability has become one of the main issues restricting its practical application.In this thesis,the power conversion efficiency and humidity resistance of the device are improved by adding oleylamine molecules into the hole-transport layer material basing on Spiro-OMe TAD.The specific contents are as follows:(1)Spiro-OMeTAD is doped with different concentrations of long carbon chain hydrophobic oleylamine molecules.It is found that the hydrophobicity and flatness of the hole-transport layer are improved after doping.X-ray photoelectron spectroscopy shows that there is a chemical interaction between oleylamine and perovskite material,which is helpful to passivate interface defects and improve the power conversion efficiency of the device.The transient photocurrent/photovoltage decay curve and electrochemical impedance spectroscopy shows that the doping increases the interfacial charge extraction rate,reduces the interfacial charge transfer resistance and increases the interfacial recombination resistance.In the grazing incidence fluorescence test,it can be found that the emission peak of doped perovskite materials has a blue shift,indicating that the doping of oleylamine molecules passivates the defects of perovskite active layer.It also verifies that there is a strong chemical interaction between oleylamine molecules and perovskite.Due to defect passivation and improved charge transfer,oleylamine doping improves the efficiency of the device.Under the condition of simulating standard sunlight AM 1.5G and 100m W/cm~2,the power conversion efficiency of the device increases from 17.82(±1.47)%to 20.68(±0.77)%(about 16.05%)with optimum efficiency reaching21.57%.(2)The high humidity accelerated aging experiment was designed to study the effect of oleylamine doped Spiro-OMe TAD hole transport layer on the humidity stability of perovskite.It is found that after aging in the relative humidity environment of 50%,60%,70%,80%and 85%respectively for 1hour,large number of undoped devices fail(the failure rate is 85.7%)while failure rate of the doped device with 80μL oleylamine is only 28.6%.Better storage-stability was achieved for OA doped devices.As such,oleylamine doping improves the moisture resistance of the device,which is due to the strong hydrophobicity of the molecule.(3)Perovskite films are prepared by vacuum annealing.The effects of annealing temperature and time on the power conversion efficiency of perovskite solar cells are studied.It is found that vacuum annealing is helpful to improve the power conversion efficiency of devices.This study provides a useful reference for the preparation of high efficiency and high stability perovskite solar cells.This paper includes 39 figures,4 tables and 109 references. |
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