Analysis of Optical Losses in High-Efficiency CuInS2-Based Nanocrystal Luminescent Solar Concentrators: Balancing Absorption versus Scattering

Abstract

Luminescent solar concentrators (LSCs) use down-converting luminophores embedded in a waveguide to absorb sunlight and deliver high irradiance, narrowband output light for driving photovoltaic and other solar energy conversion devices. Achieving a technologically useful level of optical gain requires bright, broadly absorbing, large-Stokes-shift luminophores incorporated into low-loss waveguides, a combination that has long posed a challenge to the development of practical LSCs. The recent introduction of giant effective Stokes shift semiconductor nanocrystal (NC) phosphors for LSC applications has led to significant performance improvements by increasing solar absorption while reducing escape cone and nonradiative losses compounded by reabsorption, placing increased emphasis on the importance of minimizing parasitic waveguide losses caused by scattering from NC aggregates and optical imperfections. Here, we report a detailed analysis of optical losses in polymer–NC composite waveguide LSCs based on CuInS...