Potential of thermotropic layers to prevent overheating: a review

This paper aims to present a representative rather than exhaustive review of recent research on thermotropic materials, which have the potential for being produced on the large scale required for solar energy system applications. Thermochromic and variably light scattering materials are treated, with brief discussions of the physical switching mechanisms, the spectra of the materials in the low-temperature, high-transmittance and high-temperature, low- transmittance states, long-term stability and system simulation. The integrated values of visible (luminous) and solar transmittance above and below the switching temperature are given to allow a qualitative comparison of the different materials and identification of appropriate applications.