Interface-engineered durable polymer-based solar concentrator with high reflectance and corrosion-resistance

Next-generation concentrated solar power (CSP) systems require lightweight solar reflectors (LSRs) that simultaneously achieve high solar reflectance, mechanical robustness, and long-term environmental stability. However, conventional reflector architectures remain constrained by the high weight of rigid substrates and the limited durability of lightweight alternatives. Here, a multifunctional SiO 2 -Ag-YSZ multilayer was engineered on carbon fiber-reinforced polymer (CFRP) substrates via magnetron sputtering to overcome the intrinsic low reflectance and poor surface stability of CFRP. The optimized multilayer exhibited broadband solar reflection with weak angular dependence, achieving an initial mean solar-weighted reflectance ( SWR ) of 95.97 ± 0.15% (n = 3) over 300-2500 nm. A representative specimen exhibited a peak solar reflectance of 99.92% and an average mid-infrared reflectance of approximately 99% over 2.5-15 μm. Following accelerated salt-spray and QUV exposure, the mean SWR decreased by 1.34% and 0.95% after 720 and 480 h, respectively (n = 3 for each test). The optimized coating exhibited a static WCA of 142.35 ± 1.52° and qualitatively shed droplets from an inclined surface, demonstrating strong hydrophobicity and water-shedding behavior. The optimized coating exhibited a critical scratch load for severe spallation of 56.5 ± 1.24 mN and a Class 4B cross-cut adhesion rating. These results demonstrate that interface engineering can combine high optical performance, hydrophobic water shedding, accelerated environmental resistance, and mechanical integrity in lightweight CFRP-based solar reflectors for CSP applications.