  Recent advances in the field of vertically stacked 2D materials have revealed
a rich exciton landscape. In particular, it has been demonstrated that
out-of-plane electrical fields can be used to tune the spectral position of
spatially separated interlayer excitons. Other studies have shown that there is
a strong hybridization of exciton states, resulting from the mixing of
electronic states in both layers. However, the connection between the
twist-angle dependent hybridization and field-induced energy shifts has
remained in the dark. Here, we investigate on a microscopic footing the
interplay of electrical and twist-angle tuning of moir\'e excitons in MoSe$_2$
homobilayers. We reveal distinct energy regions in PL spectra that are clearly
dominated by either intralayer or interlayer excitons, or even dark excitons.
Consequently, we predict twist-angle-dependent critical electrical fields at
which the material is being transformed from a direct into an indirect
semiconductor. Our work provides new microscopic insights into experimentally
accessible knobs to significantly tune the moir\'e exciton physics in
atomically thin nanomaterials.
