The ECPL signal can be interpreted as a precise indicator of the rate of change of the PL intensity with excitation density. In the absence of any interactions, the PL scales linearly with intensity, which results in a null ECPL response. A sub-linear PL trend correlates with a negative ECPL response. This implies that the PL in the presence of both the pump pulses is lower than twice the PL from each of the individual pulses. The decay of the ECPL signal corresponds to the time it takes for the photo-generated population to return to a linear PL regime, if that exists for the sample under study.