PbS QDs are highly appealing sensitizers due to their broad and tunable absorption spectra which can span the NIR region (650-2000 nm) through well-established synthetic control of their diameter. The PbS-rubrene/DBP system has shown visible UC emission from excitations up to 1100 nm. Successful solid-state NIR-to-visible UC systems employing PbS quantum dots as the sensitizer and rubrene as the annihilator (see Figure , b) were reported in 2016 with EQEs of under 0.0003%. Since this initial demonstration, there have been reports which have improved the efficiencies of this system using mirrors and cavities, with champion EQEs of 0.06% reported by M. Wu, et al. in 2021 via the use of a Fabry-Perot cavity. Still, using cavities severely limits the broadband absorption, and therefore deters the application of this structure to applications such as photovoltaics, night vision, and anti-counterfeiting. Consequently, an approach at the device engineering level is urgently needed to enhance the absorption and efficiency of these devices.