Image of a glass. (Representational image) Laurel Glass
China’s researchers are moving closer to creating building materials to generate their own clean power. Luminescent solar concentrators (LSCs) are emerging as a promising solution, combining transparency with the ability to harvest solar energy.
These devices use semitransparent fluorescent glass that absorbs part of the sunlight, emits light, and directs it to solar cells placed on the edges for power generation.
Until now, most fluorescent glasses for LSCs were made by embedding nanocrystals. While effective in laboratories, nanocrystal production is costly and difficult to scale. The process consumes large amounts of solvents, takes a long time, and has a low yield.
On top of that, once the glass is damaged, the emitters cannot be recycled, making them disposable and wasteful.
To overcome these challenges, scientists have been looking for ways to produce fluorescent glass through simpler, one-step thermal treatments supporting recycling and sustainable use.
A breakthrough material from China
A research team led by Professor Xiyan Li of Nankai University, China, has claimed the development of a new material that could transform the field. In their study, the team synthesized a yellow-emissive material called ETP2SbCl5 phosphor using a simple solution process at room temperature. By applying heat, the material could also be turned into glass.
The new glass showed impressive performance. The team reported a power conversion efficiency of 5.56 percent and an optical efficiency of 32.5 percent in a small 3×3×0.5 cm³ device. Importantly, the glass remained transparent enough for practical use, with an average light transmission of 78.3 percent.
The researchers explained, “We first visualize the distortion of [SbCl5] pyramid during the phase transition from α, through β, to G-ETP2SbCl5 by Ab initio molecular dynamics (AIMD), and further reveal its effects on broadened and red-shifted emission.”
High efficiency with added benefits
The new solar glass has other advantages beyond energy conversion. It can effectively absorb ultraviolet light below 420 nanometers and generate a strong emission through a process called self-trapped exciton (STE) emission.
This emission reached a photoluminescence quantum yield (PLQY) of about 52.6 percent, helping guide light to the solar cells positioned along the glass edges.
“The fabricated fluorescent glasses exhibit an average vision transmission of 78.3 percent. They could effectively absorb the UV light (< 420 nm) and realize the self-trapped exciton (STE) emission with a PLQY of ~52.6 percent,” the team summarized their results.
“Taking advantage of their great waveguide performance, a portion of sunlight and the fluorescence could be conducted to the photovoltaic devices that coupled on the edges. And we achieve the highest power conversion and optical efficiencies of ~5.56 percent and ~32.5 percent, respectively, on a 3×3×0.5 cm3 LSC device.”
Recyclable and self-healing solar glass
The most remarkable property of this new material is its recyclability. Unlike conventional nanocrystal-based LSCs, this glass can undergo reversible transitions between phosphor and glass states. Heating the glass to 200°C (392°F) enables it to heal itself and be reused.
Even after ten cycles of being transformed back and forth between phosphor and glass, the material still kept 95 percent of its original performance. This makes it a long-lasting, low-waste option for future solar technologies.
“Besides the self-healing property at 200°C, reversible transitions between phosphor and glass phases have been detected,” the researchers highlighted its broader potential in the press release.
“Even after undergoing 10 cycles of phosphor-glass transitions, the final recycled phosphors still maintained ~95% of their initial PL performance, enabling them to be further used in other fields, such as phosphor converted-LED or anti-counterfeiting, etc., as effective as freshly synthesized phosphors, underscoring its role in sustainable energy solutions for the low-carbon era.”
This development represents a major step toward affordable, recyclable, and efficient solar glass. If scaled up, future buildings could be designed with windows that not only let light in but also generate clean electricity while lasting much longer than current solar materials.
The research was published in the journal Light: Science & Applications.
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