Band-Gap Tuning in All-Inorganic CsPbxSn1–xBr3 Perovskites

Heidi A. Schwartz, Hannah Laurenzen, Asma Marzouk, Manuel Runkel, Kai Oliver Brinkmann, Detlef Rogalla, Thomas Riedl, Sahel Ashhab, Selina Olthof

2021ACS Applied Materials & Interfaces36 citationsDOI

Abstract

We investigate all-inorganic perovskite CsPbxSn1–xBr3 thin films to determine the variations in the band gap and electronic structure associated with the Pb/Sn ratio. We observe that the band gap can be tuned between 1.86 eV (x = 0) and 2.37 eV (x = 1). Intriguingly, this change is nonlinear in x, with a bowing parameter of 0.9 eV; furthermore, a slight band gap narrowing is found for low Pb content (minimum x ∼ 0.3). The wide tunability of the band gap makes CsPbxSn1–xBr3 a promising material, e.g., for a wide-gap subcell in tandem applications or for color-tunable light-emitting diodes. Employing photoelectron spectroscopy, we show that the valence band varies with the Pb/Sn ratio, while the conduction band is barely affected.

Topics & Concepts

Materials scienceBand gapBowingX-ray photoelectron spectroscopyPerovskite (structure)Direct and indirect band gapsSemimetalValence bandConduction bandOptoelectronicsAnalytical Chemistry (journal)Valence (chemistry)Thin filmSpectroscopyCrystallographyNanotechnologyElectronNuclear magnetic resonancePhysicsChemistryTheologyQuantum mechanicsChromatographyPhilosophyPerovskite Materials and ApplicationsThermal Expansion and Ionic ConductivitySolid-state spectroscopy and crystallography

Band-Gap Tuning in All-Inorganic CsPb<i><sub>x</sub></i>Sn<sub>1–<i>x</i></sub>Br<sub>3</sub> Perovskites

Abstract

Topics & Concepts