Upon introduction of the optimal 3 mM TCA between PbS and rubrene/DBP, we observe a sharp EQE increase at all PbS film thicknesses. Excitingly, we achieved the highest EQE in our experiments for the thickest PbS films (50 mg/mL) allowing an absorption up to 6.2% of incident 808 nm light without the use of cavities or mirrors (Figure ). We hypothesize that the massive improvements in EQE originate from (1) an improvement in energy transfer from PbS QDs, and (2) alleviated BT from rubrene/DBP to PbS QDs (vide infra). Based on atomic force microscopy (AFM) measurements, we isolated the thickness of 3 mM TCA to be approximately 10 nm (see SI Figure and). This thickness of 3 mM TCA and the higher singlet energy level of TCA support our hypothesis that TCA alleviates FRET-based energy BT from rubrene/DBP to PbS QDs (φBT) (see Figure ). Additionally, the triplet level of TCA lies near the PbS bandgap and above the rubrene triplet, allowing and facilitating the energy transfer in the forward direction.