The EMAS results in Figure are evidence for the successful injection of electrons and holes into PbS to a similar degree. Hole injection into semiconductor QDs, in particular lead chalcogenides, is challenging presumably due to the smaller stability of holes . We argue that the relative ease with which this is achieved here originates in the periodically oscillating (67 Hz) potential applied to the film due to which holes are created for a comparably short time span. In addition, the IHO working electrodes provide a ΔA noise level on the order of 0.1 mOD, rendering this technique sensitive also for highly incomplete carrier injection. The induced absorption in the reductive direction found in all measurements here is counterintuitive and requires a more detailed discussion: we argue that it is the result of the long measurement time for each potential step (~30 min) and limited stability of the QDs in the electrolyte (see Figure ). For each spectrum taken at a new potential, the absorption spectrum at the OCP is taken as a (new) reference, but if the background absorption during the following 30 min increases, a net-positive ΔA is possible. The 200 mOD increase in ΔA after 14 h (Figure ) is supporting evidence that, on average, an increase on the order of 200/28 ≈ 7 mOD for each potential step by this process is plausible. The broadband increase in absorption in Figure hints toward additional scattering as the main reason for this change. Such scattering may be further impacted electrochemically, e.g. by reducing Pb 2+ to Pb 0 to form a strongly scattering layer around the QDs. In this scenario, the filling of the conduction band can result in a positive ΔA if the bleach due to Pauli blocking is overcompensated by the increase in background absorption.