Published April 10, 2022 | Version v1

The Role of SnF2 Additive on Interface Formation in All Lead-Free FASnI3 Perovskite Solar Cells

  • 1. Zentrum für Sonnenenergie- und Wasserstoff-Forschung
  • 2. University Hasselt
  • 3. Centre national de la recherche scientique, France
  • 4. University of Antwerp

Description

Tin-based perovskites are promising alternative absorber materials for lead-free perovskite solar cells but need strategies to avoid fast tin (Sn) oxidation. Generally, this reaction can be slowed down by the addition of tin fluoride (SnF2) to the perovskite precursor solution, which also improves the perovskite layer morphology. Here, we analyze the spatial distribution of the additive within formamidinium tin triiodide (FASnI3) films deposited on top of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hole transporting layers. Employing Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and a combination of hard and soft X-ray photoelectron spectroscopy (HAXPES/XPS), we find that (i) SnF2 preferably accumulates at the PEDOT:PSS/ perovskite interface accompanied by (ii) the formation of an ultrathin SnS interlayer with an effective thickness of ∼1.2 nm.

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Additional details

Funding

European Commission
PERCISTAND - Development of all thin-film PERovskite on CIS TANDem photovoltaics 850937