Enhancing the photovoltaic responses of MAPbI₃ poly-crystalline perovskite films via adjusting the properties of PEDOT:PSS hole transport material with a low-polarity solvent treatment process

The surface and electrical characteristics of the poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) materials are manipulated using a low-polarity solvent treatment process, which influences the formation and nucleation/crystal growth process of the CH₃NH₃PbI₃ (MAPbI₃) perovskite films and thereby determining the crystal orientation and grain size. The hydrophilicity of the PEDOT:PSS composite material fabricated on the ITO/glass sample is reduced with the xylenes solvent treatment or a hexamethyldisilazane:xylenes solvent mixture treatment, which can be used to form the photo-active perovskite crystals and thereby reducing the photocurrent hysteresis of the fabricated perovskite based photovoltaic devices. It is worthwhile to mention that the non-perfectness of closed-loop in the photocurrent density-voltage curves under the forward and backward scans can be used as an indicator to assess the properties of the MAPbI₃ films. Our findings can facilitate the development of perovskite based optoelectronic devices.