By Ashwini Sakharkar 16 Aug, 2024
Collected at: https://www.techexplorist.com/leaf-like-solar-concentrators-aim-enhance-solar-energy-capture/87263/
Since its inception in the 1970s, the luminescent solar concentrator (LSC) has been at the forefront of revolutionizing solar energy capture by utilizing luminescent materials to convert and concentrate sunlight onto photovoltaic (PV) cells. Unlike traditional concentrators that rely on mirrors and lenses, LSCs have the unique ability to harvest diffuse light, making them ideal for applications such as building-integrated photovoltaics, where their semi-transparency and vibrant colors provide aesthetic appeal.
However, the challenge of scaling up LSCs to cover large areas has been hindered by issues such as the self-absorption of photoluminescent (PL) photons within the waveguide. Addressing these limitations, researchers at Ritsumeikan University in Japan have proposed an innovative “leaf LSC” model that shows great promise in revolutionizing the collection and transfer of light to photovoltaic cells.
The innovative leaf LSC design tackles the scalability issue by utilizing interconnected luminescent components that mimic leaves on a tree. As outlined in the Journal of Photonics for Energy (JPE), this setup involves positioning luminescent plates around a central luminescent fiber, with the plates’ sides facing the fiber. This configuration enables incident photons to be converted into PL photons by the plates, which then travel through the fiber and are collected at its tip by a PV cell.
Furthermore, to bolster efficiency, clear light guides connect multiple fibers to a single PV cell, effectively expanding the incident area of the LSC while minimizing photon losses from self-absorption and scattering.
This innovative modular approach to LSC design offers multiple benefits. By decreasing the size of individual modules, researchers have observed a noticeable improvement in photon collection efficiency. For example, a significant increase in photon collection efficiency was achieved by reducing the side length of a square leaf LSC from 50 mm to 10 mm. Additionally, the modular design allows for the seamless replacement of damaged units and the integration of cutting-edge luminescent materials as they become available.
In addition to these advancements, researchers have integrated techniques from traditional planar LSCs, such as edge mirrors and tandem structures, into the leaf LSC design to further enhance the system’s efficiency. Through their experiments, they were able to analytically determine the optical efficiency of these leaf-like structures based on the spectrum and intensity of incident light using a single-spot excitation technique.
“These findings demonstrate a creative approach that advances the concept of luminescent solar concentrators to effectively guide solar energy toward adjacent photovoltaic devices,” said JPE Editor-in-Chief Sean Shaheen, professor of engineering and physics at the University of Colorado Boulder. “By combining scalable, bio-inspired designs with enhancements in optical engineering, the authors have increased the efficiency of their devices toward what is needed for practical use.”
Optimizing photon collection in LSCs has the potential to pave the way for highly flexible and scalable solar energy solutions. This innovative approach to energy harvesting has the power to transform the use of solar concentrators, enhancing their efficiency and adaptability for a wide range of applications, from large-scale installations to building-integrated systems.
As the technology continues to progress, it promises to substantially improve the performance of solar energy systems and contribute to more sustainable energy solutions.
Journal reference:
- Hiroto Nishimura, Kohei Okada, Atsuya Suzuki, Yuta Mizuno, Ichiro Fujieda. Enhanced photon collection in leaf-inspired luminescent solar concentrators. Journal of Photonics for Energy, 2024; DOI: 10.1117/1.JPE.14.035501
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