We unravel the influence of quasiparticle screening in the nonequilibrium exciton dynamics of monolayer ${\mathrm{WS}}_2$. We report pump photon energy-dependent exciton blue- and redshifts from time-resolved-reflectance contrast measurements. Based on a phenomenological model, we isolate the effective impact of excitons and free carriers on the renormalization of the quasifree particle band gap, exciton binding energy, and linewidth broadening. By this, our work not only provides a comprehensive picture of the competing phenomena governing the exciton dynamics in ${\mathrm{WS}}_2$ upon photoexcitation, but also demonstrates that exciton and carrier contributions to dynamic screening of the Coulomb interaction differ significantly.

• Received 10 May 2022
• Revised 29 January 2023
• Accepted 1 February 2023

DOI:https://doi.org/10.1103/PhysRevB.107.115404