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Perovskite Chalcogenides are a new class of semiconductors, which have large chemical and structural tunability that translates to tunable band gap in the visible to infrared part of the electromagnetic spectrum. Besides this band gap tunability, they offer a unique opportunity to realize large density of states semiconductors with high carrier mobility. In this talk, I will discuss some of the experimental advances made both in my research group and in the research community on the theory, synthesis of these materials and understanding their optoelectronic properties.
Perovskite structure is composed of an octahedrally coordinated transition metal or main group element with anions such as oxygen, chalcogen or halogens. The octahedra is typically connected in the corners and the voids are filled by alkali, alkaline or rare earth elements. The valence and the size of the cations and anions can lead to different connectivity of these octahedra, which offers a knob to control both the chemical composition and the dimensionality of these materials. Moreover, the large number of elements in the periodic table can be accommodated in these extended perovskite and related structures, which allows us finer knobs to control the physical and chemical properties, in our case, we tailor light-matter interaction precisely over a broad energy range spanning the visible to infrared spectrum. We leverage this effect in early transition metal based perovskite chalcogenides and related phases to achieve properties such as highly anisotropic absorption and refraction (BaTiS3, Sr1+xTiS3), unconventional band gap evolution (BaZrS3 and Ban+1ZrnS3n+1 for n ≥ 1). Finally, I will provide a general outlook for future studies on these exciting new class of materials.
References:
1. S. Niu et al. Nature Photonics, 12, 392-396 (2018).
2. S. Niu et al. Advanced Materials 29, 1604733 (2017).
3. S. Niu et al. Chemistry of Materials, 30 (15), 4897-4901 (2018).
4. S. Niu et al. Chemistry of Materials, 30 (15), 4882-4886 (2018).
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