Under the same excitation intensity, we measured the PL of PbS films with (1) rubrene/DBP evaporated on top (orange curve), (2) 3 mM TCA and rubrene/DBP (blue curve), and (3) 6 mM TCA and rubrene/DBP (yellow curve). By integrating the PbS emission curve and using Equation , we calculated the quenching efficiency of these different configurations. We note that our measurement of φET1 is an approximation as there are changes to the optical outcoupling and non-radiative pathways that are introduced when the organic layers are deposited onto the PbS film.