Anodically electrodeposited NiO nanoflakes as hole selective contact in efficient air processed p-i-n perovskite solar cells

Nanostructured NiO as hole selective contact for perovskite solar cells is deposited on ITO from the potentiostatic anodic electrodeposition of NiOOH. Along with the large surface extension due to the honeycomb-like morphology, the electrodeposition route imparts different electrochemical features in respect to the classic sol-gel derived NiO, which are two interesting features for optoelectronic applications. CH3NH3PbI3 is deposited in ambient atmosphere on the NiO substrates to fabricate p-i-n perovskite solar cells, with PCBM and solution processed BCP as electron selective contact and silver as counter electrode. We found that the performances are strongly dependent on the deposition potential, with the PCE increasing when going from 1.00 V to 1.10 V vs Ag/AgCl. The best efficiency obtained is 16.1%, thanks to a fill -factor of 78%. Notably, the electrodeposited layer outperformed the sol-gel spin-coated one, proving the effectiveness of electrosynthesis to achieve competitive selective contacts for perovskite photovoltaics.