Performance Metrics and Loss Mechanisms in Horticulture Luminescent Solar Concentrators

Horticulture Luminescent Solar Concentrators (HLSCs) represent an innovative concept developed in recent years to promote crop yields, building upon the foundation of traditional Luminescent Solar Concentrators (LSCs). Unlike traditional LSCs, HLSCs focus on converting energy from one part of the solar spectrum (typically green) to a specific range (usually red) and aim for the converted photons to exit the device from the bottom surface rather than the edge surfaces. Thus, beyond spectral conversion, HLSCs are especially notable for their light extraction capabilities. Efficient spectral conversion and outcoupling efficiency are achieved by optimizing luminescent materials and introducing light extraction techniques. In this study, we start by examining the specific requirements of horticulture to clarify the motivation for using HLSCs. We re-evaluate and propose new optical metrics tailored to HLSCs. Additionally, we analyse potential loss channels for direct red emission and converted red emission. Utilizing Monte Carlo ray tracing method and experimental data, we further explore the factors influencing these loss channels. The key evaluation metrics for HLSC and LSC are compared to highlight the distinctions between the two, emphasizing the innovative features of the HLSC device. Our work provides a fundamental discussion on HLSCs and offers design guidelines for future HLSC research.