Full printable perovskite solar cells based on mesoscopic TiO2/Al2O3/NiO (carbon nanotubes) architecture

In this research work, for the first time, we introduced thin composite films (∼1.8   μm) made with NiO nanoparticles and single-walled carbon nanotubes (SWCNT) as alternatives to replace the commonly used carbon black/graphite counter electrode in full printable organic hole-transport layer free mesoporous perovskite solar cells. Due to the relative thick carbon black/graphite counter electrodes, which are typically ∼10   μm thick, charge collection and batch to batch reproducibility of this type devices are significantly limited. We find an appreciated power conversion efficiency of 12.7% can be achieved for the CH 3 NH 3 PbI 3 perovskite solar cell using mesoscopic TiO 2 /Al 2 O 3 framework structure in combination with a thin NiO/SWCNT counter electrode under standard reporting conditions. Electronic impedance spectroscopy measurements reveal efficient charge collection ability for perovskite devices using thin NiO/SWCNT counter electrodes compared to the conventional carbon black/graphite counter electrode, and thus can efficiently deliver photocurrent.