MEM-C IRG-1: Quantum-Cutting Nanocrystals in High-Efficiency Monolithic Bilayer Luminescent Solar Concentrators Materials Research Science and Engineering Center DMR-1719797 2019 Christine Luscombe, Devin MacKenzie, Daniel R. Gamelin Molecular Engineering Materials Center (MEM-C) University of Washington, Seattle Nanocrystal (NC) luminescent solar concentrators (LSCs) represent a promising clean-energy technology capable of concentrating direct and diffuse light to reduce the area of photovoltaic (PV) cells – which are energetically costly to manufacture – required to meet energy demands. We have been developing Yb3+-doped CsPbX3 (X = Cl, Br) perovskite NCs that efficiently convert single high-energy photons into pairs of low-energy photons, generating photoluminescence quantum yields approaching 200%. This process – known as quantum cutting – can improve LSC efficiencies by converting poorly used blue photons into near-infrared photons that are absorbed perfectly by silicon solar cells. These findings led to invention of a fundamentally new and simple monolithic bilayer LSC device structure that capitalizes on the unique properties of quantum-cutting Yb3+-doped CsPbX3 NCs. We are developing Yb3+-doped CsPbX3 nanocrystals that can convert the energy from absorption of single blue photons into the energy of emission of pairs of near-infrared photons – quantum cutting. We are also developing a new and unique technology that partners such quantum-cutting materials with conventional luminescent solar concentrators (LSCs) to massively reduce thermalization losses in LSCs. Our so-called monolithic bilayer LSC is a unique technology that does not require complex wiring or current matching. Using a combination of experimental data and models, we predict that monolithic bilayer LSCs will improve the performance of best-in-class NC LSCs by at least 19%. We are developing luminescent solar concentrators (LSCs) based on quantum-cutting Yb3+:CsPbCsPbX3 nanocrystals (NCs) that have documented photoluminescent quantum yields as high as ~200%. Through a combination of solution-phase 1D LSC measurements and modeling, we demonstrated that Yb3+:CsPbX3 NC LSCs show negligible intrinsic reabsorption losses, and we used these data to model the performance of large-scale 2D LSCs based on these NCs. We extended the modeling to predict the flux gains of a proposed monolithic bilayer LSC. Because of the exceptionally high PLQYs of Yb3+:CsPbX3 NCs, the optimized bilayer device has a projected flux gain of 63 for dimensions of 70 x 70 x 0.1 cm3, representing performance enhancement of at least 19% over that of a state-of-the-art commercial CuInS2 LSC alone. Milstein, T. J.; Kroupa, D. M.; Gamelin, D. R., Nano Lett. 2018, 18, 3792. Cohen, T. A.; Milstein, T. J.; Kroupa, D. M.; MacKenzie, J. D.; Luscombe, C.; Gamelin, D. R., J. Mater. Chem. A 2019 DOI: 10.1039/C9TA01261C.