Optimization of Photovoltaic Performance for Luminescent Solar Concentrator Systems

Citation

Phelan, Megan Elisabeth (2023) Optimization of Photovoltaic Performance for Luminescent Solar Concentrator Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/aqhb-s069. https://resolver.caltech.edu/CaltechTHESIS:02232023-035632589

Abstract

The luminescent solar concentrator (LSC), an emerging photovoltaic (PV) technology with myriad potential application areas, could help further spur global solar adoption. At its core, an LSC absorbs and down-shifts incident irradiation via luminophores, and then redirects the emitted photoluminescence through a dielectric waveguide towards small-area PV cells. Given this design, an LSC describes a planar concentrating technology that i) maintains low system costs by using small amounts of high-efficiency PV material and ii) enables concentration of both direct and diffuse irradiation. The underlying structure of an LSC—including flexibility, material versatility, and variable transparency—facilitates application areas that span utility, building integrated, and space-based solar power.

This thesis explores the optimization of LSC systems, measured based on photovoltaic performance, across each application area. We begin by examining photovoltaic device considerations for LSC integration, including device form factor, luminophore pairing, and microcell fabrication. We outline ideal component parameters for optimal LSC performance and fabricate a silicon heterojunction microcell with a record VOC of 588mV. Next, we design and fabricate single-junction LSCs for two application areas: building-integrated PV and space-based solar power. Through simulations and technoeconomic analyses, we find that such designs are able to achieve 7% efficiency with a forecasted cost as low as 2.22 $/W for the building-integrated application, and a specific power up to 11.55 kW/kg with an associated cost as low as 0.24 $/W for the space-based application. Finally, we investigate the potential to combine luminescent concentration with conventional solar technologies, including each a silicon subcell and geometric concentrators. We demonstrate that hybridization of luminescent concentrators with certain conventional designs has the potential to boost PV performance in both direct and diffuse lighting.

We conclude by investigating future directions for LSCs, including improved overall system performance, as well as next-generation designs for each building-integrated and space-based applications.

Thesis Files