Nanosheet-based printable perovskite solar cells

Perovskite solar cells (PSC) are intensively studied due to their low-cost processing and high light-to-electricity conversion efficiency. However, the difficulty of the large scale fabrication hinders their practical applications, and the structure tuning of the nanomaterials to optimize PSC is still challenging. In this study, we fabricate nanosheet-based PSCs using mesoscopic TiO2 nanosheets (NS) and p-type NiO nanosheets (NS) as electron transport material (ETM) and inorganic hole transport material (HTM), respectively. Furthermore, as the counter electrode (CE), carbon black/graphite can be applied by screen printing process to fabricate PSCs with the TiO2/ZrO2/NiO/carbon (CH3NH3PbI3) structure. The nanosheet-based PSC with printable carbon counter electrode shows a promising conversion efficency of 7.50%, significantly higher than the value of 6.40% of the device using the HTM of NiO nanoparticles (NP). The electrochemical impedance analysis exhibits that NS structured PSC can decrease the electron recombination effectively and enhance the collection of the charge carriers. This research presents a novel nanostructured PSC with printable carbon counter electrode, which is promising for PSC engineering technique and large scale manufacture with low cost.