Conduction Band Tuning by Controlled Alloying of Fe into Cs2AgBiBr6 Double Perovskite Powders

Huygen J. Jöbsis, Kostas Fykouras, Joost W.C. Reinders, Jacco van Katwijk, Joren M. Dorresteijn, Tjom Arens, Ina Vollmer, Loreta A. Muscarella, Linn Leppert, Eline M. Hutter

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Halide double perovskite semiconductors such as Cs2AgBiBr6 are widely investigated as a more stable, less toxic alternative to lead-halide perovskites in light conversion applications including photovoltaics and photoredox catalysis. However, the relatively large and indirect bandgap of Cs2AgBiBr6 limits efficient sunlight absorption. Here, it is shown that controlled replacement of Bi3+ with Fe3+ via mechanochemical synthesis results in a remarkable tunable absorption onset between 2.1 and ≈1 eV. First-principles density functional theory (DFT) calculations suggest that this bandgap reduction originates primarily from a lowering of the conduction band upon the introduction of Fe3+, and predict a direct bandgap when >50% of Bi3+ is replaced with Fe3+. The tunability of the conduction band energy is found and reflected in the photoredox activity of these semiconductors. These findings open new avenues for enhancing the sunlight absorption of double perovskite semiconductors and for harnessing their full potential in sustainable energy applications.
Original languageEnglish
Article number2306106
JournalAdvanced Functional Materials
Volume34
Issue number50
DOIs
Publication statusPublished - 2023
Externally publishedYes

Funding

E.M.H. acknowledges funding from the Dutch Research Council (NWO) under grant number VI.Veni.192.034. H.J.J. and E.M.H. are further supported by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). L.A.M. received funding from the NWO under the grant number OCENW.XS22.2.039. The authors want to thank Dr. Freddy Rabouw for facilitating the equipment for the PL experiments and Tim Prins for the useful discussions about x‐ray diffraction. K.F. and L.L. acknowledge funding from the NWO under grant number OCENW.M20.337 and computational resources provided by the Dutch National Supercomputing Center Snellius supported by the SURF cooperative.

FundersFunder number
Dutch National Supercomputing Center Snellius
SURF
Nederlandse Organisatie voor Wetenschappelijk OnderzoekOCENW.M20.337, OCENW.XS22.2.039, VI.Veni.192.034

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