Thermodynamic Limits of Photon-Multiplier Luminescent Solar Concentrators

TL;DR

This paper explores the thermodynamic limits of photon-multiplier luminescent solar concentrators (PM-LSCs), revealing unique constraints and potential advantages over traditional LSCs, especially at high brightness levels.

Contribution

It develops a new thermodynamic model for PM-LSCs, highlighting their distinct limits and design considerations compared to traditional luminescent solar concentrators.

Findings

Maximum concentration ratio depends on incident photon brightness.

PM-LSCs can outperform traditional LSCs at certain brightness levels.

Thermodynamic limits are more extreme for PM-LSCs than traditional LSCs.

Abstract

Luminescent solar concentrators (LSCs) are theoretically able to concentrate both direct and diffuse solar radiation with extremely high efficiencies. Photon-multiplier luminescent solar concentrators (PM-LSCs) contain chromophores which exceed 100\% photoluminescence quantum efficiency. PM-LSCs have recently been experimentally demonstrated and hold promise to outcompete traditional LSCs. However, we find that the thermodynamic limits of PM-LSCs are different and are sometimes more extreme relative to traditional LSCs. As might be expected, to achieve very high concentration factors a PM-LSC design must also include a free energy change, analogous to the Stokes shift in traditional LSCs. Notably, unlike LSCs, the maximum concentration ratio of a PM-LSC is dependent on brightness of the incident photon field. For some brightnesses, but equivalent energy loss, the PM-LSC has a greater maximum concentration factor than that of the traditional LSC. We find that the thermodynamic requirements to achieve highly concentrating PM-LSCs differ from traditional LSCs. The new model gives insight into the limits of concentration of PM-LSCs and may be used to extract design rules for further PM-LSC design.