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.