The aforementioned forward (ET) and backward (BT) energy transfer processes present a paradoxical simultaneous need for proximity and distance between the sensitizer and annihilator to maximize device EQEs. To address this challenge, we propose the introduction of an intermediate triplet-diffusing, FRET-blocking organic layer between the PbS QDs and rubrene layers (see Figure ). We hypothesize that the introduction of some optimal thickness of an organic semiconductor would improve EQEs by reducing the BT process. This ideal interlayer would possess a triplet energy level between that of rubrene (T1 = 1.14 eV) and the PbS QD bandgap (~1.2 eV) while possessing a singlet energy level higher than that of rubrene (S1 = 2.25 eV). As shown in Figure , this proposed device architecture prevents the parasitic BT by acting as an uphill energetic barrier while maintaining the triplet energy flow to the rubrene through downhill energy transfer processes (ET1, ET2). Here, we report the use of 5-tetracene carboxylic acid (TCA, S1 = 2.4 eV, T1 = ~1.3 eV, see Figure ) as an interlayer to improve NIR-to-visible solid-state UC. In addition to improvements in BT alleviation (i.e., reduction in φBT), we observe improvements in triplet extraction (φET1/ET) efficiencies from PbS. We report significant improvements in EQE, particularly for thicker PbS films, and systematically identify the cause of the improvement in EQE. Finally, we demonstrate the application of this novel device architecture in anticounterfeiting by depositing a patterned TCA interlayer to create intricate images under diffuse NIR irradiation.