Publication detail

Temperature-Dependent Excitonic Band Gap in Lead-Free Bismuth Halide Low-Dimensional Perovskite Single Crystals

VALASTRO, S. GAVRANOVIĆ, S. DERETZIS, I. VALA, M. SMECCA, E. LA MAGNA, A. ALBERTI, A. ČÁSTKOVÁ, K. MANNINO, G.

Original Title

Temperature-Dependent Excitonic Band Gap in Lead-Free Bismuth Halide Low-Dimensional Perovskite Single Crystals

Type

journal article in Web of Science

Language

English

Original Abstract

In this study, the optical behavior of lead-free Bi-based low-dimensional perovskite single crystals (Cs3Bi2Cl9, Cs3Bi2Br9, Cs3Bi2I9, and MA3Bi2I9) is investigated by spectroscopic ellipsometry, supported by X-ray diffraction and density functional theory calculations. All materials exhibit a strong excitonic peak resulting from photogenerated electron-hole Coulomb interactions, whereas the threshold of continuous absorption is found at higher energies. The resonances of the excitonic and continuous bands, along with exciton binding energies, are extracted through Critical Point Analysis of the ellipsometric data over a wide temperature range (from -90 degrees C to 90 degrees C), revealing subtle variations in the optical characteristics for each single crystal. These materials can be applied in optoelectronics as photodetectors because of their high stability and lower toxicity compared to their Pb-based perovskites. The optical behavior of Bi-based perovskite single crystals (Cs3Bi2Cl9, Cs3Bi2Br9, Cs3Bi2I9, and MA3Bi2I9) is studied by spectroscopic ellipsometry. A strong excitonic peak for all materials is detected, arising from photogenerated electron-hole Coulomb interactions. The threshold of continuous absorption is at higher energies. The resonances of the excitonic and continuous bands are extracted using Critical Point Analysis in the temperature range from -90 degrees C to 90 degrees C.image

Keywords

dielectric function; excitonic binding energy; Lead-free perovskites; optical bandgap; single crystal; spectroscopic ellipsometry

Authors

VALASTRO, S.; GAVRANOVIĆ, S.; DERETZIS, I.; VALA, M.; SMECCA, E.; LA MAGNA, A.; ALBERTI, A.; ČÁSTKOVÁ, K.; MANNINO, G.

Released

24. 12. 2023

Publisher

WILEY-V C H VERLAG GMBH

Location

WEINHEIM

ISBN

2195-1071

Periodical

Advanced Optical Materials

Number

2302397

State

Federal Republic of Germany

Pages from

1

Pages to

10

Pages count

10

URL

https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202302397

BibTex

@article{BUT187047,
  author="Salvatore {Valastro} and Stevan {Gavranović} and Ioannis {Deretzis} and Martin {Vala} and Emanuele {Smecca} and Antonino {La Magna} and Alessandra {Alberti} and Klára {Částková} and Giovanni {Mannino}",
  title="Temperature-Dependent Excitonic Band Gap in Lead-Free Bismuth Halide Low-Dimensional Perovskite Single Crystals",
  journal="Advanced Optical Materials",
  year="2023",
  number="2302397",
  pages="1--10",
  doi="10.1002/adom.202302397",
  issn="2195-1071",
  url="https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202302397"
}