Orbit-Orbit Interaction Effects on Light-Emitting Properties Through Intrinsic Excitons and Artificially Engineered Charge-Transfer Excitons in Hybrid Perovskites

This presentation will present our recent studies on orbit-orbit interaction effects of light-emitting properties. The hybrid perovskites are known as strong-orbital light-emitting materials. particularly, using orbit-orbit interaction provides a new approach to control the light-emitting properties in hybrid perovskites. In general, the orbit-orbit interaction can occur through electrical polarization and spin polarization between light-emitting excitons, leading to long-range and short-range orbit-orbit interactions. Here, we use circularly polarized and linearly polarized photoexcitations to manipulate the long-range and short-range orbit-orbit interactions between light-emitting excitons. Specifically, a circularly polarized photoexcitation generates in-phase electrical polarizations with parallel spin polarizations between orbitals, while a linearly polarized photoexcitation creates out-phase electrical polarizations with antiparallel spin polarizations. When electrical polarizations govern the orbit-orbit interaction, the in-phase electrical polarizations generated by circularly polarized photoexcitation provides a precondition to initiate the coherent interaction between light-emitting excitons towards developing a spontaneous amplified emission (ASE). When spin polarizations govern the orbit-orbit interaction, the antiparallel spin polarizations generated by linearly polarized photoexcitation provides the possibilities to decrease the spin flipping between bright and dark excitons, increasing the photoluminescence quantum yield (PLQY). Clearly, using electrical polarizations and spin polarizations between orbitals provides a vital method to control the light-emitting properties in hybrid perovskites. On the other hand, the light-emitting excitons can be generated both within single perovskite structures and heterostructured perovskites, leading to intrinsic excitons and charge-transfer excitons. Especially, the charge-transfer excitons formed with heterostructured perovskites can be considered as artificially engineered light-emitting excitons with facile property-tuning capabilities. This presentation will discuss the orbit-orbit interaction effects of both intrinsic excitons and charge-transfer excitons in hybrid perovskites.