Quantum-cutting Yb3+-doped perovskite nanocrystals for monolithic bilayer luminescent solar concentrators†
Luminescent solar concentrators (LSCs) can concentrate direct and diffuse solar radiation spatially and energetically to help reduce the overall area of solar cells needed to meet current energy demands. LSCs require luminophores that absorb large fractions of the solar spectrum, emit photons into a light-capture medium with high photoluminescence quantum yields (PLQYs), and do not absorb their own photoluminescence. Luminescent nanocrystals (NCs) with near or above unity PLQYs and Stokes shifts large enough to avoid self-absorption losses are well-suited to meet these needs. In this work, we describe LSCs based on quantum-cutting Yb3+:CsPb(Cl1−xBrx)3 NCs that have documented PLQYs as high as ∼200%. Through a combination of solution-phase 1D LSC measurements and modeling, we demonstrate that Yb3+:CsPbCl3 NC LSCs show negligible intrinsic reabsorption losses, and we use these data to model the performance of large-scale 2D LSCs based on these NCs. We further propose a new and unique monolithic bilayer LSC device architecture that contains a Yb3+:CsPb(Cl1−xBrx)3 NC top layer above a second narrower-gap LSC bottom layer (e.g., based on CuInS2 NCs), both within the same waveguide and interfaced with the same Si PV for conversion. We extend the modeling to predict the flux gains of such bilayer devices. Because of the exceptionally high PLQYs of Yb3+:CsPb(Cl1−xBrx)3 NCs, the optimized bilayer device has a projected flux gain of 63 for dimensions of 70 × 70 × 0.1 cm3, representing performance enhancement of at least 19% over the optimized CuInS2 LSC alone.