Interface Reactive Sputtering of Transparent Electrode for High‐Performance Monolithic and Stacked Perovskite Tandem Solar Cells

Sputtered indium tin oxide (ITO) fulfills the requirements of the top transparent electrodes (TTEs) in semitransparent perovskite solar cells (PSCs) and stacked tandem solar cells (TSCs) as well as the recombination layers in monolithic TSCs. However, the high-energy ITO particles will cause damage to the devices and reduce the photovoltaic performance. Herein, the interface reactive sputtering strategy has been proposed and implemented to construct cost-effective TTEs with high transmittance and excellent carrier transporting ability, aiming to realize high-performance semitransparent and tandem PSCs. Polyethylenimine (PEI) was chosen as the interface reactant, of which abundant amino groups on PEI can react with sputtered ITO nanoparticles so that coordination compounds can be formed during the ITO deposition process, facilitating the carrier transport at the interface of C60/PEI/ITO. Besides, the impact force of energetic ITO particles is greatly alleviated, and the intactness of the underlying C60 layer and perovskite layer is guaranteed. Thus, the prepared semitransparent subcells achieve a significantly enhanced power conversion efficiency (PCE) of 19.17%, surpassing those based on C60/ITO (11.64%). Moreover, the PEI-based devices demonstrate excellent storage stability, which maintains 98% of their original PCEs after 2000 hours. On the strength of the interface reactive sputtering ITO electrode, we successfully fabricated a stacked all-perovskite TSC with a PCE of 26.89% and a monolithic perovskite-organic TSC with a PCE of 24.33%. This work has provided a facile and instrumental solution for rendering TTEs function well in semitransparent and tandem PSCs. This article is protected by copyright. All rights reserved.