A closer look into two-step perovskite conversion with X-ray scattering

Johannes Schlipf, Pablo Docampo, Christoph J. Schaffer, Volker Körstgens, Lorenz Bießmann, Fabian Hanusch, Nadja Giesbrecht, Sigrid Bernstorff, Thomas Bein, Peter Müller-Buschbaum

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69 Citations (Scopus)

Abstract

Recently, hybrid perovskites have gathered much interest as alternative materials for the fabrication of highly efficient and cost-competitive solar cells; however, many questions regarding perovskite crystal formation and deposition methods remain. Here we have applied a two-step protocol where a crystalline PbI2 precursor film is converted to MAPbI3-xClx perovskite upon immersion in a mixed solution of methylammonium iodide and methylammonium chloride. We have investigated both films with grazing incidence small-angle X-ray scattering to probe the inner film morphology. Our results demonstrate a strong link between lateral crystal sizes in the films before and after conversion, which we attribute to laterally confined crystal growth. Additionally, we observe an accumulation of smaller grains within the bulk in contrast with the surface. Thus, our results help to elucidate the crystallization process of perovskite films deposited via a two-step technique that is crucial for controlled film formation, improved reproducibility, and high photovoltaic performance.

Original languageEnglish
Pages (from-to)1265-1269
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume6
Issue number7
DOIs
Publication statusPublished - 19 Mar 2015
Externally publishedYes

Keywords

  • confined growth
  • conversion
  • crystal size
  • GISAXS
  • Ostwald ripening
  • perovskite solar cell

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