Improving device performance of MAPbI₃photovoltaic cells by manipulating the crystal orientation of tetragonal perovskites

The properties of CH₃NH₃PbI₃(MAPbI₃) crystalline thin films and the device performance of highly efficient MAPbI₃photovoltaic cells are investigated by varying the temperature of the antisolvent from 20 °C to 50 °C during the washing enhanced nucleation (WEN) process. The surface, structural, optoelectronic and defect properties of the perovskite thin films are characterized through atomic-force microscopy, X-ray diffractometry and photoluminescence spectrometry. The experimental results show that changing the temperature of the antisolvent during the WEN process can manipulate the MAPbI₃crystalline thin films from the (110)-(002) complex phase to a (002) preferred phase. It is noted that the highest power conversion efficient of the inverted MAPbI₃photovoltaic cells is 19.30%, mainly due to the increased carrier collection efficiency and reduced carrier recombination when the temperature of the antisolvent is 30 °C.