Perovskite hetero-anionic-sublattice interfaces for optoelectronics and nonconventional electronics

The perovskite structure provides a versatile framework for functional materials and their high-quality heteroepitaxial interfaces. Perovskite halides (PH) have attracted intense interest for their application in optoelectronics. Oxides are another major class of perovskites that are widely used in fuel cells, nonconventional electronics and electrochemistry. Interfacing different perovskite oxides (POs) has led to a multitude of fascinating discoveries. By introducing anionic degree of freedom, we expect that perovskite hetero-anionic-sublattice interfaces can provide a new platform for emergent phenomena that may or may not have homo-oxygen-sublattice interface analogues. In this work, we investigate the interfaces between the all-inorganic PH CsPbBr₃, the emerging double perovskite halide (dPH) Cs₂TiBr₆ and various common POs. Based on the band alignment properties, these POs are considered to be suitable carrier transport materials (CTMs) for CsPbBr₃ and Cs₂TiBr₆ in either light-harvesting or light-emitting devices. In addition, these perovskite hetero-anionic-sublattice interfaces are found to be defect- and dangling bond-free due to compatible crystal lattices, making POs potentially outperform conventional binary transition-metal-oxide and organic CTMs. Besides optoelectronics, the potential of perovskite hetero-anionic-sublattice interfaces for nonconventional electronics is also explored. As examples, two-dimensionally confined electron-hole systems are predicted at the asymmetric interfaces in both Cs₂TiBr₆:LaAlO₃ and CsPbBr₃:LaAlO₃ superlattice structures. This finding, along with the optically active properties of PHs, may spark novel applications of light-electron interaction in perovskite systems. This work presents new opportunities for perovskite heteroepitaxial interfaces.