Scaling law for excitons in layered 2D perovskites systems: Dion-Jacobson (DJ) phases and Alternating Cation in the Interlayer space (ACI) phases

Layered two-dimensional (2D) hybrid perovskites are emerging types of semiconductor quantum wells (QWs) with highly promising opto-electronic applications. These solution-processed materials offer tunability of opto-electronic properties, which can be achieved by varying quantum well thickness (n-value). For instance, our previous work has demonstrated the scaling behavior of excitons with different quantum well thickness in Ruddlesden-Popper (RP) Perovskites. Besides the well-studied RP perovskites, there’re other crystal structures such as Dion-Jacobson (DJ) and Alternating Cation in the Interlayer space (ACI) phases, whose intrinsic exciton and charge carrier properties still remain unrevealed. Here, using optical spectroscopy, we perform detailed studies of the optical and electronics properties on DJ and ACI systems, such as exciton fine structure, electron-phonon coupling and defect states, and demonstrate their scaling behavior with quantum well thickness. These results will bridge the gap between optical properties of 2D and 3D perovskite crystals, leading to better design of opto-electronics devices. The tendency of how different 2D perovskites phases merge into unique 3D perovskite will give us a deeper understanding of the fundamental physics of perovskite materials.