This energetic difference and non-nested HOMO/LUMOs favour the formation of an exciplex between the two molecules but unfortunately such a species has been difficult to observe experimentally because of the parallel presence of aggregates. The presence of an exciplex would also explain the big difference between the PL spectra of the three molecules in mCP This complicated co-existence of monomer, aggregate, and exciplex emission in mCP host makes it impossible to calculate the real kinetics of these systems. Thus, the calculated kinetics values do not represent the truth, but an estimation of the systems modelled as single species environments. The latter observation indicates that among other detrimental factors, guest-guest aggregation quenching plays an important role at higher current densities.