The luminescent solar concentrator (LSC) has been around since the 1970s, with the goal of improving solar energy capture by using luminescent materials to convert and concentrate sunlight onto photovoltaic (PV) cells. This technology offers advantages over traditional concentrators by being able to harvest diffuse light and being used in applications like building-integrated photovoltaics. However, challenges arise when trying to scale up LSCs to cover large areas due to issues such as self-absorption of photoluminescent photons within the waveguide.
Researchers at Ritsumeikan University in Japan have proposed an innovative “leaf LSC” model to tackle these limitations and improve the collection and transfer of light to photovoltaic cells. This new design addresses the scalability problem by utilizing smaller interconnected luminescent components that function like leaves on a tree. Placing luminescent plates around a central luminescent fiber enables incident photons to be converted into photoluminescent photons by the plates, travel through the fiber, and be collected at its tip by a PV cell.
One of the main advantages of the leaf LSC design is its modular approach, which offers several benefits. By reducing the lateral size of individual modules, researchers have found that the efficiency of photon collection improves significantly. For example, decreasing the side length of a square leaf LSC from 50 mm to 10 mm led to a notable increase in photon collection efficiency. Additionally, the modular design allows for easy replacement of damaged units and integration of advanced luminescent materials in the future.
To further enhance the efficiency of the leaf LSC design, researchers have incorporated techniques from traditional planar LSCs, such as edge mirrors and tandem structures. Their experiments have shown that the optical efficiency of these leaf-like structures can be calculated analytically based on the spectrum and intensity of incident light using a single-spot excitation technique. According to JPE Editor-in-Chief Sean Shaheen, the innovative approach taken by the researchers has significantly improved the efficiency of their devices, bringing them closer to practical use.
Optimizing photon collection in LSCs through innovative designs like the leaf LSC model may pave the way for more flexible and scalable solar energy solutions. This approach to energy harvesting could revolutionize the application of solar concentrators, making them more efficient and adaptable for various uses, ranging from large-scale installations to building-integrated systems. As the technology continues to advance, it holds the promise of greatly enhancing the performance of solar energy systems and contributing to more sustainable energy solutions.
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