A research team led by Nanjing University has introduced a transparent, colorless, and unidirectional solar concentrator that can be directly coated onto standard window glass. Utilizing cholesteric liquid crystal (CLC) multilayers with submicron lateral periodicities, this diffractive-type solar concentrator (CUSC) selectively guides sunlight toward the edge of the window where photovoltaic cells are installed. The study appears in PhotoniX.
Unlike conventional luminescent or scattering-based concentrators, which often suffer from visual distortion, low efficiency, and poor scalability, the new CUSC achieves broadband polarization-selective diffraction and waveguiding without compromising clarity. The device maintains a high average visible transmittance (64.2%) and color rendering index (91.3), enabling clean energy generation without altering the appearance of the window.
"By engineering the structure of cholesteric liquid crystal films, we create a system that selectively diffracts circularly polarized light, guiding it into the glass waveguide at steep angles," said Dr. Dewei Zhang, co-first author. "This allows up to 38.1% of incident green light energy to be collected at the edge."
Experiments showed that a 1-inch-diameter prototype could directly power a 10-mW fan under sunlight. Modeling suggests a typical 2-meter-wide CUSC window could concentrate sunlight by 50 times, significantly reducing the number of photovoltaic cells required by up to 75%. The system supports integration with high-performance PV cells such as gallium arsenide for enhanced power conversion.
The multilayered CLC films are fabricated via photoalignment and polymerization techniques and are scalable via roll-to-roll manufacturing. The design remains stable under long-term exposure and can be retrofitted onto existing windows for sustainable urban upgrades.
"The CUSC design is a step forward in integrating solar technology into the built environment without sacrificing aesthetics," said Professor Wei Hu. "It represents a practical and scalable strategy for carbon reduction and energy self-sufficiency."
Future work will focus on enhancing broadband efficiency, polarization control, and adapting the technology for agricultural greenhouses and transparent solar displays. Their vision: to turn passive glass into active, energy-generating surfaces worldwide.
Story Source:
Materials provided by Chinese Society for Optical Engineering. Note: Content may be edited for style and length.
Journal Reference:
Cite This Page:
New Research Reveals Humans Have a Remote Touch “Seventh Sense”
A Parasite Carried by Billions Has a Secret Life Inside the Brain
Why Are My Ears Ringing? Here’s What Experts Want You To Know About Tinnitus
Melting Antarctic Ice Did the Opposite of What Scientists Expected
Stay informed with ScienceDaily’s free email newsletter, updated daily and weekly. Or view our many newsfeeds in your RSS reader:
Keep up to date with the latest news from ScienceDaily via social networks:
Tell us what you think of ScienceDaily — we welcome both positive and negative comments. Have any problems using the site? Questions?

source