Three-Dimensional Solar Harvesting with Transparent Spectral Selective Photovoltaics in Agrivoltaics

Although photovoltaic (PV) solar cells have been widely used for a variety of applications, several critical issues are yet to be addressed, including further enhanced power conversion efficiency (PCE) and their 2D solar harvesting with limited land availability. It has been reported that traditional PV installations require approximately 22,000 square miles to power the entire United States—posing a significant barrier, particularly in urban and agricultural settings. A unique dual modality of PV system has been proposed and implemented for both power generation and crop photosynthesis, namely, agrivoltaics. This system installs PV panels over the crops while harvesting solar for PV electricity generation and, at the same time, integrates with crop cultivation, which is a promising solution to optimize land utilization. However, for opaque PV panels, sunlight is often obstructed, potentially impacting plant growth and yield. To address this critical issue, a 3D solar harvesting concept has been proposed and experimentally investigated. By placing multiple layers of transparent PV panels parallel, sunlight can penetrate multiple layers and generate electricity on each PV, significantly enhancing the solar harvesting surface area. Most importantly, sunlight can also be collected by the crops underneath for effective photosynthesis. Among various PV materials, dye-sensitized solar cells (DSSCs) using porphyrin-based dyes have demonstrated potential for spectral modulation, optimizing both electricity generation and crop illumination. This review focuses on a novel approach to a 3D solar harvesting system via a multi-layered PV architecture for agrivoltaics. Also discussed are the current challenges in agrivoltaics, spectral selective mechanisms, and 3D solar harvesting architecture that show promise for sustainable energy production and land-efficient solar power deployment.