Solar-driven plasmonic nano-enhanced liquid crystal smart window for self-powered adaptive thermal and optical regulation

The growing demand for energy-efficient building technologies has accelerated the development of adaptive smart window systems capable of regulating solar radiation and reducing cooling loads. In this study, a self-powered electro-optic smart window based on plasmonic nanomaterial-enhanced nematic liquid crystal (PNLC) was developed for adaptive thermal and optical regulation. Gold nanoparticles (AuNPs) were incorporated into the liquid crystal matrix to enhance dielectric anisotropy and electro-optic responsiveness, while an integrated thin-film photovoltaic (PV) module enabled autonomous operation. The optimised PNLC composition containing 0.05 wt% AuNPs increased dielectric anisotropy from 8.2 to 9.7, resulting in a reduced threshold voltage of approximately 2.3 V. UV – Vis – NIR spectral analysis revealed high visible transparency (~75–78%) and strong near-infrared attenuation, with average NIR transmittance decreasing from approximately 79% to 35–40%, corresponding to an attenuation efficiency of nearly 50–55%. The device exhibited rapid electro-optic switching with a minimum response time of approximately 12 ms at 5.5 Vrms. Under simulated solar irradiation (200–1000 W/m2), the integrated PV module delivered an operating voltage of approximately 3.3 V, enabling self-powered switching. Thermal evaluation showed a surface temperature reduction from 46.7°C to 30.8°C and an indoor heat gain reduction of 54.6%.