Leaf-shaped solar concentrators to enable flexible, scalable renewable energy

In another solar energy development, scientists have further evolved luminescent solar concentrators (LSCs), a technology that dates back to the 1970s, since the early days of photovoltaic cells.

Researchers at Ritsumeikan University, Japan developed a “leaf LSC” model that promises to overcome the limitations of LSCs by enhancing the collection and transfer of light to photovoltaic cells.

Traditional LSCs are challenging to scale up for larger applications as they rely on mirrors and lenses.

The luminescent solar concentrators can capture diffuse light and have been integrated into photovoltaic applications where their semi-transparent and colorful characteristics provide aesthetic advantages.

Improving photon collection efficiency

However, the new maple leaf-like model design improves photon collection efficiency, reduces losses, and makes the system more adaptable and replaceable, which could lead to more practical and widespread use of solar concentrators.

The main challenge of scalability drove experts to design the leaf LSC by employing smaller, interconnected luminescent components that operate akin to leaves on a tree.

The study noted that this innovative setup involves placing luminescent plates around a central luminescent fiber, with the plates’ sides facing the fiber.

“This arrangement allows 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.”

Clear light-guides connected multiple fibers to a single PV cell, increasing efficiency by increasing the area collecting lighting and minimizing photon losses from self-absorption and scattering.

Reducing module size to increase efficiency in solar concentrator

As a result of the new modular solar concentrator design, scientists observed an improvement in photon collection efficiency because of the smaller individual modules.

The size of a square leaf LSC came down to 10 mm from 50 mm, greatly increasing efficiency.

The modular design also allows for easy replacement of damaged units and easy integration of new luminescent materials as they are developed.

Scientists noted in a statement that the experiments showed that the optical efficiency of these leaf-like structures can be calculated analytically.

This was based on the spectrum and intensity of incident light, using a single-spot excitation technique.

Sean Shaheen, JPE Editor-in-Chief, professor of engineering and physics at the University of Colorado Boulder, and a fellow of the Renewable and Sustainable Energy Institute expressed:

“These findings demonstrate a creative approach that advances the concept of luminescent solar concentrators to effectively guide sunlight toward adjacent photovoltaic devices.”

Shaheen added that 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.

Flexible, scalable solar energy

The new leaf approach paves the way for more flexible and scalable solar energy solutions.

Striving to revolutionize solar concentrator applications, scientists took the concept of energy harvesting and made the new solar energy systems more efficient and adaptable.

This technology allows for large-scale installations to build integrated photovoltaic systems.

Experts believe that with advancing technology, the leaf LSC shows promise in significantly enhancing the performance of solar energy systems and contributing to more sustainable energy solutions.

The study was published last month [July 19, 2024] in the Journal of Photonics for Energy .