Details
| Original language | English |
|---|---|
| Article number | 1604995 |
| Journal | Advanced functional materials |
| Volume | 27 |
| Issue number | 6 |
| Publication status | Published - 10 Feb 2017 |
Abstract
Despite their outstanding photovoltaic performance, organic–inorganic perovskite solar cells still face severe stability issues and limitations in their device dimension. Further development of perovskite solar cells therefore requires a deeper understanding of loss mechanisms, in particular, concerning the origin and impact of trap states. Here, different surface properties of submicrometer sized CH 3NH 3PbI 3 particles are studied as a model system by photoluminescence spectroscopy to investigate the impact of the perovskite crystal surface on photoexcited states. Comparison of single crystals with either isolating or electron-rich surface passivation indicates the presence of positively charged surface trap states that can be passivated in case of the latter. These surface trap states cause enhanced nonradiative recombination at room temperature, which is a loss mechanism for solar cell performance. In the orthorhombic phase, the origin of multiple emission peaks is identified as the recombination of free and bound excitons, whose population ratio critically depends on trap state properties. The dynamics of exciton trapping at 50 K are observed on a time-scale of tens of picoseconds by a simultaneous population decrease and increase of free and bound excitons, respectively. These results emphasize the potential of surface passivation to further improve the performance of perovskite solar cells.
Keywords
- bound excitons, organic–inorganic perovskites, surface modifications, surface trap states, time-resolved photoluminescence
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
Sustainable Development Goals
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In: Advanced functional materials, Vol. 27, No. 6, 1604995, 10.02.2017.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Impact of Crystal Surface on Photoexcited States in Organic-Inorganic Perovskites
AU - Birkhold, Susanne T.
AU - Zimmermann, Eugen
AU - Kollek, Tom
AU - Wurmbrand, Daniel
AU - Polarz, Sebastian
AU - Schmidt-Mende, Lukas
N1 - Funding information: The authors thank the Baden-Württemberg Foundation (Projects “SUPERSOL”; program “Biomimetic Materials Synthesis”), the Federal Ministry of Education and Research (BMBF) (Project “MesoPIN”) and the Carl Zeiss Foundation for financial support.
PY - 2017/2/10
Y1 - 2017/2/10
N2 - Despite their outstanding photovoltaic performance, organic–inorganic perovskite solar cells still face severe stability issues and limitations in their device dimension. Further development of perovskite solar cells therefore requires a deeper understanding of loss mechanisms, in particular, concerning the origin and impact of trap states. Here, different surface properties of submicrometer sized CH 3NH 3PbI 3 particles are studied as a model system by photoluminescence spectroscopy to investigate the impact of the perovskite crystal surface on photoexcited states. Comparison of single crystals with either isolating or electron-rich surface passivation indicates the presence of positively charged surface trap states that can be passivated in case of the latter. These surface trap states cause enhanced nonradiative recombination at room temperature, which is a loss mechanism for solar cell performance. In the orthorhombic phase, the origin of multiple emission peaks is identified as the recombination of free and bound excitons, whose population ratio critically depends on trap state properties. The dynamics of exciton trapping at 50 K are observed on a time-scale of tens of picoseconds by a simultaneous population decrease and increase of free and bound excitons, respectively. These results emphasize the potential of surface passivation to further improve the performance of perovskite solar cells.
AB - Despite their outstanding photovoltaic performance, organic–inorganic perovskite solar cells still face severe stability issues and limitations in their device dimension. Further development of perovskite solar cells therefore requires a deeper understanding of loss mechanisms, in particular, concerning the origin and impact of trap states. Here, different surface properties of submicrometer sized CH 3NH 3PbI 3 particles are studied as a model system by photoluminescence spectroscopy to investigate the impact of the perovskite crystal surface on photoexcited states. Comparison of single crystals with either isolating or electron-rich surface passivation indicates the presence of positively charged surface trap states that can be passivated in case of the latter. These surface trap states cause enhanced nonradiative recombination at room temperature, which is a loss mechanism for solar cell performance. In the orthorhombic phase, the origin of multiple emission peaks is identified as the recombination of free and bound excitons, whose population ratio critically depends on trap state properties. The dynamics of exciton trapping at 50 K are observed on a time-scale of tens of picoseconds by a simultaneous population decrease and increase of free and bound excitons, respectively. These results emphasize the potential of surface passivation to further improve the performance of perovskite solar cells.
KW - bound excitons
KW - organic–inorganic perovskites
KW - surface modifications
KW - surface trap states
KW - time-resolved photoluminescence
UR - http://www.scopus.com/inward/record.url?scp=85007411583&partnerID=8YFLogxK
U2 - 10.1002/adfm.201604995
DO - 10.1002/adfm.201604995
M3 - Article
VL - 27
JO - Advanced functional materials
JF - Advanced functional materials
SN - 1616-301X
IS - 6
M1 - 1604995
ER -