Issue 12, 2022

Black single crystals of lead-free perovskite Cs2Ag(Bi:Ru)Br6 with an intermediate band

Abstract

The toxicity of lead halide perovskites hinders their application in optoelectronics. Lead-free Cs2AgBiBr6 is regarded as a promising candidate due to its excellent photoelectric properties. However, its excessively wide band gap limits its absorption in the visible region. Herein, we incorporated the transition metal Ru3+ into Cs2AgBiBr6 and obtained black single crystals by a hydrothermal method. The absorption edge was extended from ∼660 nm to the near-infrared region (∼1200 nm). When 1.8% of Ru was doped, the double perovskite structure was still maintained and the lattice shrank since some Bi3+ was replaced by smaller Ru3+. Theoretical calculation indicates that after Ru-doping, a new intermediate band was generated inside the pristine band gap of Cs2AgBiBr6 as experimentally confirmed by Valence Band X-ray Photoelectron Spectroscopy. The intermediate band lies below the Fermi surface and is mainly dominated by the Ru-d orbital. Moreover, with the fabrication of a near-infrared (NIR) photodetector, a NIR response from the Ru-doped Cs2AgBiBr6 was realized. This work provides an effective way of regulating the energy band structure of Cs2AgBiBr6 and extends the application of lead-free perovskites for optoelectronic devices, such as NIR detectors and intermediate band solar cells.

Graphical abstract: Black single crystals of lead-free perovskite Cs2Ag(Bi:Ru)Br6 with an intermediate band

Supplementary files

Article information

Article type
Paper
Submitted
06 мар 2022
Accepted
06 май 2022
First published
09 май 2022
This article is Open Access
Creative Commons BY license

Mater. Adv., 2022,3, 4932-4937

Black single crystals of lead-free perovskite Cs2Ag(Bi:Ru)Br6 with an intermediate band

Z. Zhang, G. Liu, W. Guo, X. Li, Y. Zhang, C. Wu, B. Qu, J. Shi, Z. Chen and L. Xiao, Mater. Adv., 2022, 3, 4932 DOI: 10.1039/D2MA00264G

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