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Low Temperature Synthesis of Stable γ‐CsPbI 3 Perovskite Layers for Solar Cells Obtained by High Throughput Experimentation
Author(s) -
Becker Pascal,
Márquez José A.,
Just Justus,
AlAshouri Amran,
Hages Charles,
Hempel Hannes,
Jošt Marko,
Albrecht Steve,
Frahm Ronald,
Unold Thomas
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201900555
Subject(s) - materials science , perovskite (structure) , photoluminescence , phase (matter) , charge carrier , luminescence , spectroscopy , analytical chemistry (journal) , optoelectronics , energy conversion efficiency , thin film , carrier lifetime , chemical engineering , nanotechnology , chemistry , engineering , physics , organic chemistry , chromatography , quantum mechanics , silicon
The structural phases and optoelectronic properties of coevaporated CsPbI 3 thin films with a wide range of [CsI]/[PbI 2 ] compositional ratios are investigated using high throughput experimentation and gradient samples. It is found that for CsI‐rich growth conditions, CsPbI 3 can be synthesized directly at low temperature into the distorted perovskite γ‐CsPbI 3 phase without detectable secondary phases. In contrast, PbI 2 ‐rich growth conditions are found to lead to the non‐perovskite δ‐phase. Photoluminescence spectroscopy and optical‐pump THz‐probe mapping show carrier lifetimes larger than 75 ns and charge carrier (sum) mobilities larger than 60 cm 2 V −1 s −1 for the γ‐phase, indicating their suitability for high efficiency solar cells. The dependence of the carrier mobilities and luminescence peak energy on the Cs‐content in the films indicates the presence of Schottky defect pairs, which may cause the stabilization of the γ‐phase. Building on these results, p–i–n type solar cells with a maximum efficiency exceeding 12% and high shelf stability of more than 1200 h are demonstrated, which in the future could still be significantly improved, judging on their bulk optoelectronic properties.