Final-state effects account for the increase in intensity of W B in the photoemission spectra of the reduced films compared to the pristine material, which is consistent with the increased LSPR intensity in the UV-Vis-NIR spectra with reduction. Accounting for W A and W B as unscreened and screened final states due to the conduction band electrons, we assign W C as a more strongly localized state resulting from cation intercalation. Most likely, the lowest binding energy W C corresponds to a polaronic state that involves a lattice distortion and localization of the electronic charge, which would change the local electronic environment and shift the W 4f binding energy. When comparing the photoemission peaks, we note that W C is much narrower compared to the other two components in Figure , indicating a longer lifetime of that state, which is expected for a more localized state (Table ). Significant charge localization is also expected to be correlated with structural rearrangements of the tungsten octahedra.