Bandgap and Photoluminescence Tunability of Lead-Free Cs3Bi2(Br,I)9 Solid Solution Compounds

Hashimoto H, Oka R, Hayakawa T, Brabec C (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Physica Status Solidi-Rapid Research Letters Wiley-VCH Verlag

DOI: 10.1002/pssr.202300241

Abstract

Herein, lead-free, mixed-halide perovskites of cesium bismuth bromide/iodide are synthesized by a hydrothermal method, and their structures and optical properties of the solid solution compounds are examined. The synthesized compounds exhibit X-ray diffraction patterns similar to that of trigonal Cs3Bi2Br9 (CBB), whose reflections are shifted to lower angles depending on the experimental iodine content. Very interestingly, even with the excessive introduction of iodine content in nominal, the symmetry of the crystals is kept to be trigonal, indicating that bromide CBB and iodide Cs3Bi2I9 (CBI) are crystallographically mixed in a facile way, although the stable crystal form of CBI is hexagonal. The optical properties of bandgap energy Eg and photoluminescence (PL) for the synthesized crystals are also examined. It is found that Eg decreases and PL peak position is correspondingly shifted to a longer wavelength with an increase in the experimental iodine content due to their band-to-band transitions. Moreover, first-principles calculation suggests the reduction of Eg with iodine content and the varied nature of band structure from direct (trigonal CBB) to indirect (trigonal CBI) transition. These novel findings can make the proposed strategy successful for developing lead-free, mixed-halide Bi-based perovskite crystals with the tunability of their optical properties.

Authors with CRIS profile

Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET) (i-MEET)

Additional Organisation(s)

Graduiertenkolleg 2495/2 Energiekonvertierungssysteme: von Materialien zu Bauteilen (Energy Conversion Systems: From Materials to Devices)

Involved external institutions

Nagoya Institute of Technology / 名古屋工業大学 Nagoya Kōgyō Daigaku JP Japan (JP)

How to cite

APA:

Hashimoto, H., Oka, R., Hayakawa, T., & Brabec, C. (2023). Bandgap and Photoluminescence Tunability of Lead-Free Cs3Bi2(Br,I)9 Solid Solution Compounds. Physica Status Solidi-Rapid Research Letters. https://doi.org/10.1002/pssr.202300241

MLA:

Hashimoto, Haruto, et al. "Bandgap and Photoluminescence Tunability of Lead-Free Cs3Bi2(Br,I)9 Solid Solution Compounds." Physica Status Solidi-Rapid Research Letters (2023).

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