Polymer‐Assisted Single‐Step Slot‐Die Coating of Flexible Perovskite Solar Cells at Mild Temperature from Dimethyl Sulfoxide

• Published in: ChemPlusChem (Weinheim, Germany) Germany), 2021-10, Vol.86 (10), p.1442-1450
• Main Authors: Bisconti, Francesco, Giuri, Antonella, Marra, Gianluigi, Savoini, Alberto, Fumo, Paolo, Marrazzo, Rosamaria, Zanardi, Stefano, Corso, Gianni, Po, Riccardo, Biagini, Paolo, Quadrivi, Eleonora, Suhonen, Riikka, Kraft, Thomas M., Ylikunnari, Mari, Listorti, Andrea, Corcione, Carola Esposito, Colella, Silvia, Rizzo, Aurora
• Format: Article
• Language: English
• Subjects: perovskites; photovoltaic devices; polymers; slot-die coating; solar energy conversion
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.202100251

The industrialization of perovskite solar cells relies on solving intrinsic‐to‐material issues. To reach record efficiencies perovskite deposition needs to be finely adjusted by multi‐step processes, in a humidity free glove‐box environment and by means of hardly scalable techniques often associated with toxic solvents and anti‐solvent dripping/bath. Herein, the use of polymeric material is proposed to deposit perovskite layers with easy processability. To the scope, a starch‐polymer/perovskite composite is developed to suit slot‐die coating technique requirement, allowing the deposition of hybrid halide perovskite material in a single straightforward step without the use of toxic solvents, and in uncontrolled humid environment (RH up to 70 %). The starch‐polymer increases the viscosity of the perovskite precursor solutions and delays the perovskite crystallization that results in the formation of perovskite films at mild temperature (60 °C) with good morphology. These innovative inks enables the fabrication of flexible solar cells with p‐i‐n configuration featured by a power conversion efficiency higher than 3 %. . Overall, this approach can be exploited in the future to massively reduce perovskite manufacturing costs related to keeping the entire fabrication line at high‐temperature and under nitrogen or dry conditions. The slot‐die coating deposition of perovskite in an uncontrolled humid environment (RH up to 70 %), following an accurate characterisation of the perovskite material, is reported in this work. By the addition of a templating polymeric agent, it was possible to avoid the use of the toxic and hardly scalable antisolvent bath. Furthermore, a proof‐of‐concept flexible device with slot die coated hole‐ and electron‐transporter materials was also realised.