Improvement on the performance of perovskite solar cells by doctor-blade coating under ambient condition with hole-transporting material optimization

Numerous fabrication methods have been developed for high-efficiency perovskite solar cells (PSCs). However, these are limited to spin-coating processes in a glove box and are yet to be commercialized. Therefore, there is a need to develop a controllable and scalable deposition technique that can be carried out under ambient conditions. Even though the doctor-blade coating technique has been widely used to prepare PSCs, it is yet to be applied to high-efficiency PSCs under ambient conditions (RH similar to 45%, RT similar to 25 degrees C). In this study, we conducted blade-coating fabrication of modified high-efficiency PSCs under such conditions. We controlled the substrate temperature to ensure phase transition of perovskite and added dimethyl sulfoxide (DMSO) to the perovskite precursor solution to delay crystallization, which can facilitate the formation of uniform perovskite films by doctor-blade coating. The as-prepared perovskite films had large crystal domains measuring up to 100 mu m. Solar cells prepared from these films exhibited a current density that was enhanced from 17.22 to 19.98 mA/cm(2) and an efficiency that was increased from 10.98% to 13.83%. However, the open-circuit voltage was only 0.908 V, probably due to issues with the hole-transporting layer. Subsequently, we replaced poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with NiOx as the hole-transporting material and then prepared higher-quality perovskite films by blade-coating under ambient conditions. The as-prepared perovskite films were preferably orientated and had large crystal domains measuring up to 200 mu m; The open-circuit voltage of the resulting PSCs was enhanced from 0.908 to 1.123V, while the efficiency increased from 13.83% to 15.34%. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.