Enhancement of the hole conducting effect of NiO by a N₂ blow drying method in printable perovskite solar cells with low-temperature carbon as the counter electrode

In this article, we demonstrate for the first time a mesoscopic printable perovskite solar cell (PSC) using NiO as the hole transporting material and low-temperature processed carbon as the counter electrode. A single deposition method assisted by N₂ blow drying was used for the deposition of MAPbI₃ on a TiO₂/ZrO₂/NiO screen-printed electrode. As the final step a low-temperature processing (i.e. 75 °C) carbon counter layer was fabricated on MAPbI₃ by a blade coating method. It is found that the capping layer thickness of MAPbI₃ has a significant effect on the device efficiency, especially when NiO is introduced as a hole transporting material into the structure. Electrochemical impedance spectroscopy demonstrates good charge transport characteristics for the device with a thin MAPbI₃ capping layer obtained by the N₂ blow drying method. Our best performing device demonstrated a remarkable photovoltaic performance with a short-circuit current density (J_sc) of 22.38 mA cm^-2, an open circuit voltage (V_oc) of 0.97 V, and a fill factor (FF) of 0.50 corresponding to a photo-conversion efficiency (PCE) of 10.83%. Moreover, the un-encapsulated device exhibited advantageous stability over 1000 h in air in the dark.