Fundamental Efficiency Limits of Transition-Metal Dichalcogenide Solar Cells with Carrier Multiplication and Hot-Carrier Effects

≃ 1.3 eV shifts toward ∼1.0 eV, with reversible efficiencies above 50%. CM does not raise the reversible HC limit; at finite κ, it only redistributes part of the same excess photon energy into collected current. Monolayer TMDs show negligible CM benefit, whereas bulk-like TMDs can exhibit large HC gains only when electron-phonon cooling is strongly suppressed. These results identify narrow-bandgap, optically strong TMDs as the more plausible beyond-SQ route.