Novel Low-Temperature Process for Perovskite Solar Cells with a Mesoporous TiO2 Scaffold

5 years ago

Novel Low-Temperature Process for Perovskite Solar Cells with a Mesoporous TiO2 Scaffold

Markus Mundus, Seunghun Lee, Martin Hermle, Stefan W. Glunz, Simone Mastroianni, Andreas Hinsch, Patricia S.C. Schulze, Laura E. Mundt, Alexander J. Bett, Jan Christoph Goldschmidt, Uli Würfel, Kristina Winkler

The most efficient organic–inorganic perovskite solar cells (PSCs) contain the conventional n-i-p mesoscopic device architecture using a semiconducting TiO₂ scaffold combined with a compact TiO₂ blocking layer for selective electron transport. These devices achieve high power conversion efficiencies (15–22%) but mainly require high-temperature sintering (>450 °C), which is not possible for temperature-sensitive substrates. Thus far, comparably little effort has been spent on alternative low-temperature (<150 °C) routes to realize high-efficiency TiO₂-based PSCs; instead, other device architectures have been promoted for low-temperature processing. In this paper the compatibility of the conventional mesoscopic TiO₂ device architecture with low-temperature processing is presented for the first time with the combination of electron beam evaporation for the compact TiO₂ and UV treatment for the mesoporous TiO₂ layer. Vacuum evaporation is introduced as an excellent deposition technique of uniform compact TiO₂ layers, adapting smoothly to the rough fluorine-doped tin oxide substrate surface. Effective removal of organic binders by UV light is shown for the mesoporous scaffold. Entirely low-temperature-processed PSCs with TiO₂ scaffold reach encouraging stabilized efficiencies of up to 18.2%. This process fulfills all requirements for monolithic tandem devices with high-efficiency silicon heterojunction solar cells as the bottom cell.

Publisher URL: http://dx.doi.org/10.1021/acsami.7b05718

DOI: 10.1021/acsami.7b05718