Design and demonstration of a simple, low-cost transparent solar absorber for glass window applications

Windows are a major source of heat loss from buildings in cold climates. Developing coatings for windows that retain high visible transparency and strongly absorbs solar energy in the near infrared region can help reduce energy consumption and cost for indoor heating. Nanophotonic structures based on metasurface and metamaterials have shown great potential for such applications. Unfortunately, most of the designs proposed so far are difficult to fabricate or expensive. In this work, we report the experimental demonstration of a low-cost alternative based on Ni/SiO 2 /Ni multilayer structure. The device provides a large increase in temperature under solar illumination while retaining high visible transmission. Our optical and thermal measurements reveal that the performance of the device remains stable over a long period. The combination of low cost, ease of fabrication, good optical and thermal performance, and long-term stability makes it a promising design for passive heating of windows in cold climates.