A Nanjing University team developed a transparent solar concentrator that coats ordinary window glass. The device employs cholesteric liquid crystal (CLC) multilayers with submicron-scale periodic structures to function as a diffractive solar concentrator (CUSC). It channels sunlight toward the window’s edges, where photovoltaic cells capture the energy. The findings were published in PhotoniX.
Next-Gen Solar Coating Balances Clarity, Color, and Clean Energy
Unlike conventional concentrators prone to distortion and low efficiency, the new CUSC uses polarization-selective diffraction and waveguiding to maintain clear windows. With 64.2% visible transmittance and a 91.3 color rendering index, it generates clean energy without altering appearance.
Dr. Dewei Zhang, co-first author, said the tailored liquid crystal films selectively diffract circularly polarized light, directing it into the glass waveguide at steep angles. “This setup harvests up to 38.1% of incoming green light energy at the window’s edge.”
Prototype to Potential
A 1-inch prototype powered a 10-mW fan, while simulations suggest a 2-meter CUSC window could boost sunlight 50-fold and cut photovoltaic cell use by 75%. The system can also pair with high-efficiency PV materials such as gallium arsenide to boost power conversion.
Researchers fabricate the multilayered CLC films through photoalignment and polymerization and can scale them up with roll-to-roll manufacturing. The design withstands long-term exposure and retrofits onto existing windows, providing a sustainable path for urban upgrades.
“The CUSC design marks progress in embedding solar technology into architecture without compromising aesthetics,” said Professor Wei Hu. “It provides a practical and scalable approach to reducing carbon emissions and achieving energy independence.”
Looking ahead, the researchers aim to improve broadband efficiency and polarization control, while expanding applications to agricultural greenhouses and transparent solar displays. Their long-term goal is to transform ordinary glass into active, energy-producing surfaces worldwide.
Read the original article on: Science Daily
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