Efficient Blade-Coated Wide-Bandgap Perovskite Solar Cells via Interface Engineering

Johnpaul K Pious; Pascal N Rohrbeck; Roland Widmer; Aaron H Oechsle; Sunil B Shivarudraiah; Radha K Kothandaraman; Severin Siegrist; Chih-Jen Shih; Thomas A Jung; Stefan A L Weber; Ayodhya N Tiwari; Fan Fu

doi:10.1021/acsami.5c03709

Efficient Blade-Coated Wide-Bandgap Perovskite Solar Cells via Interface Engineering

ACS Appl Mater Interfaces. 2025 Apr 23;17(16):24040-24047. doi: 10.1021/acsami.5c03709. Epub 2025 Apr 9.

Authors

Affiliations

¹ Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, Dübendorf 8600, Switzerland.
² Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany.
³ Department of Chemistry, University of Mainz, Duesbergweg 10-14, Mainz 55128, Germany.
⁴ Nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, Dübendorf 8600, Switzerland.
⁵ Laboratory for X-ray Nanoscience and Technologies, Center for Photon Science, Paul Scherrer Institute, Villigen PSI 5232, Switzerland.
⁶ Institute for Chemical and Bioengineering, ETH Zürich, Zürich 8093, Switzerland.
⁷ Institute for Photovoltaics, University of Stuttgart, Pfaffenwaldring 47, Stuttgart 70569, Germany.

PMID: 40203492
DOI: 10.1021/acsami.5c03709

Abstract

Most high-efficiency all-perovskite tandem solar cells use a "superstrate" configuration, integrating a wide-bandgap (WBG) top subcell and a narrow bandgap (NBG) bottom subcell. However, this structure suffers oxidative degradation due to easily air-exposable bottom NBG subcells. A "substrate" structure offers improved stability for tandems by encapsulating the NBG top subcell with the air-stable WBG bottom subcell. However, conventional WBG perovskite solar cells (PSCs) using water-based NiO_x interlayers hinder their fabrication on top of the NBG subcells in an inert atmosphere. To overcome this, we developed a nonaqueous NiO_x nanoparticle dispersion, enabling interlayer fabrication inside a glove box. The blade-coated NiO_x interlayer facilitated the formation of a densely packed 2PACz (2-(9H-carbazol-9-yl)ethyl]phosphonic acid) monolayer hole transporting layer (HTL). The energetically aligned 2PACz molecules reduced minority carrier recombination at the NiO_x/perovskite interface. As a result, the fully scalable 1.77 eV WBG PSCs employing a NiO_x/2PACz hybrid HTL delivered a champion power conversion efficiency of 17.4%.

Keywords: NiOx interlayer; blade coating; buried interface engineering; perovskite solar cell upscaling; scalable charge transport layers; wide-bandgap perovskites.