Transparent solar concentrator changes windows into clean energy sources
A team from Nanjing University has developed a transparent, colorless solar center plant that can be applied directly to regular glass windows, allowing buildings to generate electricity without changing their appearance. The innovation, reported in Photonix, is based on cholesteric liquid crystal multiple layers to divert sunlight to window edges equipped with photovoltaic cells.
Conventional lumines center and scattering concentrators are often confronted with problems such as distortion, inefficiency and limited scalability. The new concentrator, on the other hand, reaches polarization-selective Difraction and wave guide while retaining clarity, with an average visible transmission of 64.2% and a color reproduction index of 91.3.
“By engineering the structure of cholesteric liquid films, we create a system that selectively breaks down circularly polarized light, which leads it in the glass wave guide under steep corners,” Co-first author Dr. Dewei Zhang. “This allows a maximum of 38.1% of the incident green light energy to be collected on the edge.”
A prototype of one inch has successfully driven a 10-MW fan under sunlight, and modeling predicts that a two-meter-wide window of sunlight could concentrate with a factor of 50. This efficiency could reduce the need for photovoltaic cells by a maximum of 75%, especially in combination with advanced materials such as Galliumarsenide.
The films are manufactured by photo lines and polymerization processes, making them suitable for roll-to-roll production. They remain stable under extensive exposure and can be applied afterwards to existing windows, and offer a sustainable solution for urban infrastructure.
“The CUSC design is a step forward in integrating solar technology in the built environment without sacrificing aesthetics,” said Professor Wei Hu. “It represents a practical and scalable strategy for carbon reduction and energy-self-provision.”
Walking research will refine broadband efficiency and polarization control, with potential applications ranging from agricultural greenhouses to transparent solar displays. The ultimate goal is to transform passive glass into active, energy-generating surfaces worldwide.
Research report:Colorless and Unidirectional Difractive Type Solar Central Centers Compatible with existing windows
