Inkjet‐Printed TiO2/Fullerene Composite Films for Planar Perovskite Solar Cells.

Perovskite solar cells have garnered and held international research interest, due to ever‐climbing power conversion efficiency values, now >25 %. Some high efficiency configurations utilize a compact TiO2 layer underneath a mesoporous TiO2 layer, both of which require high temperature annealing steps that could hinder perovskite commercialization. To address the high thermal budget, we chose to use inkjet‐printing to combine the two layers into a single TiO2 film, which incorporates both nanoparticle and molecular precursor as well as organic fullerene additives. We printed the ink on fluorine‐doped tin oxide, and after annealing at various temperatures, we found that 400 °C was the optimum annealing temperature for the inkjet‐printed electron transport layers, which is significantly lower than the 500 °C required to anneal typical mesoporous TiO2 films. [ABSTRACT FROM AUTHOR]