Influence of interlayer interactions on the relaxation dynamics of excitons in ultrathin MoS 2 .

Interlayer interactions play a crucial role in modifying the optical and electronic properties of layered materials in a complex way, which is of key importance for the performance of the optoelectronic devices based on these novel materials. In this contribution, we performed an investigation into the underlying influence of interlayer interactions on the relaxation dynamics of excitons in ultrathin MoS 2 using the femtosecond transient absorption spectroscopy technique. The experimental results manifest that interlayer interactions in bilayer MoS 2 can largely facilitate the exciton-phonon scattering process and inhibit the radiative recombination process, which consequently accelerates the relaxation rate of A excitons and results in the decrease of the relaxation lifetime of A excitons in bilayer MoS 2 .