Wavelength-selective solar photovoltaic systems to enhance spectral sharing of sunlight in agrivoltaics

Over the past decade, “agriphotovoltaic” (APV) or “agrivoltaic” systems have emerged as a promising integrated food-energy system enabling the dual use of land for agricultural activities and solar energy. Unfortunately, conventional opaque silicon solar panels often fail to meet the light requirements of most shade-intolerant plants due to the excessive shading they cause. However, there is potential for solutions that exploit the fact that plants do not require the full solar irradiance spectrum to grow. In fact, a full spectrum could, in some instances, be detrimental to their growth. This is where the concept of wavelength-selective solar photovoltaic (WSPV) technologies comes into play. These technologies consider the absorption profiles of plants, and they allow for the transmission of light at the wavelengths most useful for photosynthesis while reflecting or absorbing less useful ones to be converted to electricity. We offer a comprehensive review of the reported solutions for achieving wavelength selectivity to the general reader. We discuss their status and barriers to overcome, together with perspectives on and strategies for WSPV implementation in APV systems. Current evidence reveals that these technologies effectively share the sunlight, though most of them remain to be evaluated at full scale with regard to their impact on crops and energy performance. We also explore the limits of solar cell efficiency under conditions of spectral sharing for crop production, aiming to inspire future progress in WSPV technologies.