Origin of Ionic Inhomogeneity in MAPb(IxBr1-x)3Perovskite Thin Films Revealed by In-Situ Spectroscopy during Spin Coating and Annealing
(2020) In ACS Applied Materials and Interfaces 12(27). p.30343-30352- Abstract
Irradiation-induced phase segregation in mixed methylammonium halide perovskite samples such as methylammonium lead bromide-iodide, MAPb(IxBr1-x)3, is being studied intensively because it limits the efficiency of wide band gap perovskite solar cells. It has been postulated that this phenomenon depends on the intrinsic ionic (in)homogeneity in samples already induced during film formation. A deeper understanding of the MAPb(IxBr1-x)3 formation processes and the influence of the halide ratio, solvents, and the perovskite precursor composition as well as the influence of processing parameters during deposition, e.g., spin coating and annealing parameters, is still lacking. Here, we use a fiber optic-based optical in-situ setup to study the... (More)
Irradiation-induced phase segregation in mixed methylammonium halide perovskite samples such as methylammonium lead bromide-iodide, MAPb(IxBr1-x)3, is being studied intensively because it limits the efficiency of wide band gap perovskite solar cells. It has been postulated that this phenomenon depends on the intrinsic ionic (in)homogeneity in samples already induced during film formation. A deeper understanding of the MAPb(IxBr1-x)3 formation processes and the influence of the halide ratio, solvents, and the perovskite precursor composition as well as the influence of processing parameters during deposition, e.g., spin coating and annealing parameters, is still lacking. Here, we use a fiber optic-based optical in-situ setup to study the formation processes of the MAPb(IxBr1-x)3 series on a subsecond time scale during spin coating and thermal annealing. In-situ UV-vis measurements during spin coating reveal the influence of different halide ratios, x, in the precursor solution on the preferential crystallization of the phase. Pure bromide samples directly form a perovskite phase, samples with high iodide content form a solvate intermediate phase, and samples with a mixed stoichiometry between 0.1 ≤ x ≤ 0.6 form both. This leads to a heterogeneous formation process via two competing reaction pathways, that leads to a heterogeneous mixture of phases, during spin coating and rationalizes the compositional heterogeneity of mixed bromide-iodide samples even after annealing.
(Less)
- author
- Rehermann, Carolin ; Merdasa, Aboma LU ; Suchan, Klara LU ; Schröder, Vincent ; Mathies, Florian and Unger, Eva L. LU
- organization
- publishing date
- 2020-07-08
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- formation process, homogeneity, in-situ spectroscopy, mixed halides, perovskites
- in
- ACS Applied Materials and Interfaces
- volume
- 12
- issue
- 27
- pages
- 10 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- pmid:32510922
- scopus:85088206557
- ISSN
- 1944-8244
- DOI
- 10.1021/acsami.0c05894
- language
- English
- LU publication?
- yes
- id
- 21351edc-d306-4a79-b6bc-bb35e48fc193
- date added to LUP
- 2021-01-12 11:00:31
- date last changed
- 2024-05-16 01:47:28
@article{21351edc-d306-4a79-b6bc-bb35e48fc193,
abstract = {{<p>Irradiation-induced phase segregation in mixed methylammonium halide perovskite samples such as methylammonium lead bromide-iodide, MAPb(IxBr1-x)3, is being studied intensively because it limits the efficiency of wide band gap perovskite solar cells. It has been postulated that this phenomenon depends on the intrinsic ionic (in)homogeneity in samples already induced during film formation. A deeper understanding of the MAPb(IxBr1-x)3 formation processes and the influence of the halide ratio, solvents, and the perovskite precursor composition as well as the influence of processing parameters during deposition, e.g., spin coating and annealing parameters, is still lacking. Here, we use a fiber optic-based optical in-situ setup to study the formation processes of the MAPb(IxBr1-x)3 series on a subsecond time scale during spin coating and thermal annealing. In-situ UV-vis measurements during spin coating reveal the influence of different halide ratios, x, in the precursor solution on the preferential crystallization of the phase. Pure bromide samples directly form a perovskite phase, samples with high iodide content form a solvate intermediate phase, and samples with a mixed stoichiometry between 0.1 ≤ x ≤ 0.6 form both. This leads to a heterogeneous formation process via two competing reaction pathways, that leads to a heterogeneous mixture of phases, during spin coating and rationalizes the compositional heterogeneity of mixed bromide-iodide samples even after annealing.</p>}},
author = {{Rehermann, Carolin and Merdasa, Aboma and Suchan, Klara and Schröder, Vincent and Mathies, Florian and Unger, Eva L.}},
issn = {{1944-8244}},
keywords = {{formation process; homogeneity; in-situ spectroscopy; mixed halides; perovskites}},
language = {{eng}},
month = {{07}},
number = {{27}},
pages = {{30343--30352}},
publisher = {{The American Chemical Society (ACS)}},
series = {{ACS Applied Materials and Interfaces}},
title = {{Origin of Ionic Inhomogeneity in MAPb(I<sub>x</sub>Br<sub>1-x</sub>)<sub>3</sub>Perovskite Thin Films Revealed by In-Situ Spectroscopy during Spin Coating and Annealing}},
url = {{http://dx.doi.org/10.1021/acsami.0c05894}},
doi = {{10.1021/acsami.0c05894}},
volume = {{12}},
year = {{2020}},
}