Natural molecule Niacin enables printable carbon-based mesoscopic perovskite solar cells with 17.3% efficiency

Printable carbon-based mesoscopic perovskite solar cells (MPSCs) have garnered great attention in the growing solar industry owing to their low cost, scalable manufacturing process and excellent stability. The power conversion efficiency (PCE) of MPSCs need to be improved due to serious defects in perovskite films grown in the triple-mesoporous structure. Herein, natural molecule Niacin was added to FA_0.6MA_0.4PbI₃ perovskite precursor as a dual-purpose additive for the first time to improve the performance of MPSCs. The results show that Niacin not only inhibits the formation of PbI₂ effectively, but also its carboxyl group (–COOH) can form strong coordination with Pb²⁺ to passivate defects and obtain high-quality perovskite with larger grain size. Finally, a champion PCE of 17.3% was obtained under the synergistic optimization of Niacin. Meanwhile, the unencapsulated Niacin-modified MPSCs exhibited excellent air stability, retaining 92.8% of the initial PCE after 60 days of dark storage in air. This work provides a new approach for further utilizing natural molecules to prepare high-performance MPSCs.