Room-temperature processed hole-transport layer in flexible inverted perovskite solar cell module

Metal oxide-based electrodes are considered to have a key role in the future production of perovskite solar cells (PSCs). Here, we report a high-quality hole transport material deposited by solution-processed vanadium (V) substituted NiO nanomaterial at room-temperature, which holds better electrical conductivity and hole extraction ability as a reference sample. The smaller crystallite size of vanadium-substituted NiO than that of pristine NiO, decreased the surface roughness and significantly improved the surface wetting of the perovskite film. Therefore, vanadium-substitution improved the quality of the perovskite film. Furthermore, the presence of V⁵⁺ effectively enhanced the electrical conductivity of the NiO film as determined from the photovoltaic properties of the inverted PSC. The increase in electrical conductivity promoted charge transport and reduced interfacial charge accumulation. These enhanced performances and room-temperature deposition method validate the feasibility of the V-incorporated NiO for flexible PSC module with promising efficiency.