Ultrathin Plasma Polymer Passivation of Perovskite Solar Cells for Improved Stability and Reproducibility

Despite the youthfulness of hybrid halide perovskite solar cells, their efficiencies are currently comparable to commercial silicon and have surpassed quantum‐dots solar cells. Yet, the scalability of these devices is a challenge due to their low reproducibility and stability under environmental conditions. However, the techniques reported to date to tackle such issues recurrently involve the use of solvent methods that would further complicate their transfer to industry. Herein a reliable alternative relaying in the implementation of an ultrathin plasma polymer as a passivation interface between the electron transport layer and the hybrid perovskite layer is presented. Such a nanoengineered interface provides solar devices with increased long‐term stability under ambient conditions. Thus, without involving any additional encapsulation step, the cells retain more than 80% of their efficiency after being exposed to the ambient atmosphere for more than 1000 h. Moreover, this plasma polymer passivation strategy significantly improves the coverage of the mesoporous scaffold by the perovskite layer, providing the solar cells with enhanced performance, with a champion efficiency of 19.2%, a remarkable value for Li‐free standard mesoporous n‐i‐p architectures, as well as significantly improved reproducibility. In this work, the remote plasma‐assisted vacuum deposition (RPAVD) of an ultrathin plasma polymer layer to passivate the electron selective layer/perovskite interface of perovskite solar cells is reported. The results show that the plasma polymer interface passivation improves both the photovoltaic parameters and reproducibility. Moreover, the passivation method leads to devices with higher stability under ambient conditions.