University at Buffalo, The State University of New York,
Keywords: thermal insulation, energy efficiency, and low-carbon building
Summary:Transparent windows that insulate infrared light and heat entering buildings hold promise to reduce energy consumption. Current window insulation materials based on coatings and double/triple glazing are far away from economic optimum solution to regulate the heat gain. Here we report transparent nanocomposite with engineered materials gradient consisting of a hollow network and nanoparticle hybrid composite, which exhibits excellent insulation for heat and infrared radiation. We have achieved a temperature difference of 6.9 oC by combining light-reflectance properties of metallic nanoparticles and thermal insulation of hollow shell networks, resulting in an equivalent cooling power of 396 W/m2. A high transparency of 91.0 % in the visible region has also been demonstrated with this flexible nanocomposite sheet possessing a Young’s modulus of 160 MPa. The gradient nanocomposites combine excellent UV light blocking, high visible transparency, and infrared light shielding resulting in the overall thermal insulation performance. The development of the nanocomposite with engineered materials gradient opens a new avenue of multi-functional coating techniques for various energy and optoelectronic applications.