Interface Modification For Inverted Planar Hetero-junction Perovskite Solar Cells

As “one of the world's top ten scientific and technological breakthroughs” in 2013,Hybrid organic-inorganic perovskite material is regarded as the most potential materials for developing efficient photovoltaic devices,because of its outstanding photoelectric property.In past seven years,the power convention efficiencies?PCE?have improved steadily from 3.9% to 22.1%,which is outperforming conventional polycrystalline silicon solar cells.However,the interface defects would lead to the recombination of carriers,suppress the transportation of carries,and reduce the stability of the device.In this paper,we focus on interface modification for inverted planar heterojunction solar cells.The specific contents are following.1.CH₃NH₃PbI₃ perovskite films were prepared by gas-assisted spin-coating.The effects of different delay time and gas pressure on the crystallization of the films were studied.Then the mechanism of dendritic microstructure for conventional spin-coating process was explored.The precursor supersaturation rate was increased via gas-assisted spin-coating process,which would promote the balance between the required nucleation rate and growth rate.Finally,compare the performance of the corresponding cell devices.As a result,the perovskikte solar cells can be obtained best performance with PCE of ⁸% by delay time at 3 s⁵ s and gas pressure at 0.4 MPa⁰.8 MPa.Moreover,the hysteresis of solar cells was restrained effectively.2.Interface of Inverted Planar Perovskite Solar Cells were modified by Argon Plasma-Treatment on PEDOT:PSS.Experimental results show that argon plasma treatment on the PEDOT:PSS layer effectively increases its conductivity due to the modification of the PSS ratio in the film.The argon plasma treating time directly affects the surface morphologies and contact angles of the PEDOT: PSS layer and therefore optimises the uniformity of the PEDOT:PSS layer in nanometer-scale.The improment in the chemical compositions and film morphologies of PEDOT:PSS could be beneficial to enhancing the wettability and retarding the carrier recombination.The open-circuit voltage?Voc?and short circuit current density?Jsc?of PSCs based on the treated PEDOT:PSS were both improved,resulting in the enhancement of PCE.As a result,the optimized performance was achieved by 3 min of Argon Plasma Post-Treatment on PEDOT:PSS,with PCE of 12.17%,Voc of 0.92 V,Jsc of 19.14 Am/cm²,FF of 0.69.