Mixed-valence halide perovskites

Deschene, Christina R. [Stanford Univ., CA (United States)]; Zwanziger, Clara [Stanford Univ., CA (United States)]; Matheu, Roc [Univ. de Barcelona (Spain)]; Karunadasa, Hemamala I. [Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)]

doi:10.1016/j.ccr.2025.216719

DOE OSTI · 2575157

Mixed-valence halide perovskites

Deschene, Christina R. [Stanford Univ., CA (United States)]·Zwanziger, Clara [Stanford Univ., CA (United States)]·Matheu, Roc [Univ. de Barcelona (Spain)]·Karunadasa, Hemamala I. [Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)]

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Abstract

Mixed-valence compounds—which feature an element in at least two different oxidation states—can display emergent optical and transport phenomena stemming from electron transfer between the different valences (intervalence charge-transfer; IVCT). As halide perovskites show promise as active materials in numerous optoelectronic devices, it is an opportune moment to incorporate and study the effects of mixed-valence in this versatile materials family, to access tunable electronic structures ranging from insulators to semiconductors to metals. Herein, we introduce the basic concepts of mixed-valence in molecules and discuss how these concepts may be extended to mixed-valence in extended solids. We then review the few studies of mixed valence in 3D and 2D halide perovskites and halide perovskites with mixed-valence impurities, ranging from studies in the early 1900s to the present day. In conclusion, through judicious choice of metal ion, its coordinating ligands and their geometry, and overall structural dimensionality, chemists can exert powerful synthetic control over electronic delocalization in mixed-valence perovskites, and we hope to see this intriguing materials class expand to encompass new compositions.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY Halide perovskites High-pressure studies Intervalence charge transfer Mixed valence

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Deschene, Christina R. [Stanford Univ., CA (United States)], Zwanziger, Clara [Stanford Univ., CA (United States)], Matheu, Roc [Univ. de Barcelona (Spain)], Karunadasa, Hemamala I. [Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)]. 2025-04-30. Mixed-valence halide perovskites. https://doi.org/10.1016/j.ccr.2025.216719

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