Revealing long–range orbit–orbit interaction between coherent light-emitting excitons occurring in amplified spontaneous emission in CsPbBr3 microstructures

Amplified spontaneous emission (ASE) has become a common phenomenon in hybrid perovskites by establishing coherent light-emitting excitons. This paper reports a new phenomenon that the long–range orbit–orbit interaction is established through orbital polarizations between coherent light-emitting excitons during the generation of ASE in the CsPbBr3 microrods. Essentially, when the orbital polarizations are optically generated with the same direction between coherent light-emitting excitons by using a circularly polarized pumping beam, the ASE amplitude can be largely enhanced by 22.3%, as compared to the situation when the orbital polarizations are generated with opposite directions by using linearly polarized photoexcitation in randomly orientated microstructures. This observation provides evidence that long–range orbit–orbit interaction occurs between coherent light-emitting excitons in ASE. Furthermore, the long–range orbit–orbit interaction between coherent light-emitting excitons is simultaneously increased with the ASE amplitude while increasing the pumping fluence. Therefore, the long–range orbit–orbit interaction plays an important role in developing coherent light-emitting excitons towards ASE in metal halide perovskites.