Characterizing temperature-dependent optical properties of (MA0.13FA0.87) PbI3 single crystals using spectroscopic ellipsometry
In this paper, we present spectroscopic ellipsometry measurements of (MA 0.13 FA 0.87 )PbI 3 single crystals assessed at photon energies of 0.73–6.42 eV and at temperatures between 4.4 and 400 K. At room temperature, the refractive index was dispersed as a function of frequency, which is typical of...
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Published in | Scientific reports Vol. 9; no. 1; pp. 1 - 9 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
03.12.2019
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | In this paper, we present spectroscopic ellipsometry measurements of (MA
0.13
FA
0.87
)PbI
3
single crystals assessed at photon energies of 0.73–6.42 eV and at temperatures between 4.4 and 400 K. At room temperature, the refractive index was dispersed as a function of frequency, which is typical of a semiconductor. The absorption spectrum exhibited several electronic transitions. We estimated a room temperature direct band gap of 1.66 ± 0.02 eV and exciton binding energy of 40 meV. With decreasing temperature, the refractive index increased. The room-temperature thermo-optic coefficients were −1.7 × 10
−4
and −2.5 × 10
−4
K
−1
at wavelength of 600 and 1200 nm. The exciton peak position and bandgap energy exhibited a redshift, which was attributed to a reverse ordering of the band structures. Additionally, an anomaly in exciton peak position and bandgap occurred at approximately 100–200 K due to the structural phase transition. This phenomenon was associated with the coexistence of MA/FA-disordered and MA/FA-ordered domains. Our results provide a foundation for the technological development of lead halide perovskites-based photonic devices at various temperatures. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2045-2322 2045-2322 |
DOI: | 10.1038/s41598-019-54636-7 |