Electronic States Modulation by Coherent Optical Phonons in 2D Halide Perovskites

Excitonic effects underpin the fascinating optoelectronic properties of 2D perovskites that are highly favorable for photovoltaics and light-emitting devices. Analogous to switching in transistors, manipulating these excitonic using coherent phonons could unlock new applications. Presently, a detailed understanding this underlying mechanism remains modest. Herein, origins carrier-phonon coupling transient absorption (TA) spectroscopy explicated. The exciton fine structure is modulated by optical dominated vibrational motion PbI6 octahedra via deformation potential. Originating from impulsive stimulated Raman scattering, vibrations manifest as oscillations TA spectrum comprising generation detection processes phonons. This two-step process leads unique pump- probe-energy dependence phonon modulation determined imaginary part refractive index its derivative, respectively. frequency lattice displacement inorganic dependent on organic cation. study injects fresh insights into exciton–phonon relevant emergent optoelectronics development.