CdSe/CdS-poly(cyclohexylethylene) thin film luminescent solar concentrators

Thin film luminescent solar concentrators are promising components of distributed power generation systems for building integrated photovoltaic applications. However, thin film geometries require high luminophore loading fractions to achieve sufficient absorption of sunlight, which, in the case of nanocrystal luminophores, can lead to aggregation and light scattering. In this work, we integrate CdSe/CdS nanocrystals into thin films of poly(cyclohexylethylene) at a range of loading fractions and characterize the composites with a combination of spectroscopic and simulation tools. We find that increased incident sunlight scattering is observed for the increasing luminophore loading fraction, but that the scattering is mostly limited to higher energy sunlight such that visible transmittance and haze of the samples are all greater than 89.7% and less than 8.3%, respectively. We then analyze the refractive index of the composite and show that the increase in loading fraction also affects the propagation of photoluminescence in the film, especially if the refractive index of the film is greater than that of the substrate. These studies show the importance of understanding the optical transport within thin films and provide design criteria to fabricate thin films for future implementation into building integrated photovoltaic applications.