Nanoscale mapping of chemical composition in organic-inorganic hybrid perovskite films.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31692661.
- Also identified by DOI 10.1126/sciadv.aaw6619 and PMC identifier 6814396.
- Licence recorded as CC BY-NC.
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Abstract
Lead-based organic-inorganic hybrid perovskite (OIHP) solar cells can attain efficiencies over 20%. However, the impact of ion mobility and/or organic depletion, structural changes, and segregation under operating conditions urge for decisive and more accurate investigations. Hence, the development of analytical tools for accessing the grain-to-grain OIHP chemistry is of great relevance. Here, we used synchrotron infrared nanospectroscopy (nano-FTIR) to map individual nanograins in OIHP films. Our results reveal a spatial heterogeneity of the vibrational activity associated to the nanoscale chemical diversity of isolated grains. It was possible to map the chemistry of individual grains in CsFAMA [Cs<sub>0.05</sub>FA<sub>0.79</sub>MA<sub>0.16</sub>Pb(I<sub>0.83</sub>Br<sub>0.17</sub>)<sub>3</sub>] and FAMA [FA<sub>0.83</sub>MA<sub>0.17</sub>Pb(I<sub>0.83</sub>Br<sub>0.17</sub>)<sub>3</sub>] films, with information on their local composition. Nanograins with stronger nano-FTIR activity in CsFAMA and FAMA films can be assigned to PbI<sub>2</sub> and hexagonal polytype phases, respectively. The analysis herein can be extended to any OIHP films where organic cation depletion/accumulation can be used as a chemical label to study composition.