Interfacial Investigation on Printable Carbon-Based Mesoscopic Perovskite Solar Cells with NiO x /C Back Electrode.

Solar cells with high efficiency, low cost, and high stability are the target for the new generation of solar cells. A fully printable perovskite (CH3 NH3 PbI3 ) solar cell (PSC) with device architecture FTO/TiO2 /Al2 O3 /NiOx /C is fabricated in the current research as a low-cost and relatively stable structure and is investigated to determine how different fabrication factors such as the thickness of the insulating spacer layer (Al2 O3 ) or treatments such as heat and UV-O3 treatments can affect the interfacial properties of this multilayer mesoporous structure. X-ray photoelectron spectra (XPS) show that UV-O3 treatment increases the Ni3+ (Ni2 O3 ) phase on the surface of the black nickel oxide layer leading to better charge extraction and increasing open-circuit voltage (VOC ) up to 0.945 V. We observe improved CH3 NH3 PbI3 formation inside the mesoporous layers by the PbI2 penetration at a higher temperature. Impedance spectral together with current-voltage measurements show the effect of thickness for the insulator layer in the internal and interfacial resistances and photovoltaic characteristics of the cell. The best performance of the carbon-based PSC attains power conversion efficiency of 12.1% with the thickness of the Al2 O3 layer at 450 nm.