Frenkel Excitons in Vacancy-Ordered Titanium Halide Perovskites (Cs <sub>2</sub> TiX <sub>6</sub> )
Seán R. Kavanagh, Christopher N. Savory, Shanti Maria Liga, Gerasimos Konstantatos, Aron Walsh, David O. Scanlon
Abstract
compounds. Theoretical investigations of these materials, however, consistently overestimate their band gaps, a fundamental property for photovoltaic applications. Here, we reveal strong excitonic effects as the origin of this discrepancy between theory and experiment, a consequence of both low structural dimensionality and band localization. These findings have vital implications for the optoelectronic application of these compounds while also highlighting the importance of frontier-orbital character for chemical substitution in materials design strategies.
Topics & Concepts
HalidePerovskite (structure)Vacancy defectCurse of dimensionalityPhotovoltaic systemMaterials scienceBand gapExcitonOptoelectronicsTitaniumSolar cellChemical physicsNanotechnologyChemistryInorganic chemistryComputer scienceCrystallographyPhysicsCondensed matter physicsMetallurgyMachine learningBiologyEcologyPerovskite Materials and ApplicationsCrystal Structures and PropertiesQuantum Dots Synthesis And Properties