Thermal Management Using Carbon Nanotubes Devices with Dynamic Reflectivity

Materials that have tunable reflectivity and emissivity in the infrared (IR) regime offer a compelling means to reduce buildings’ radiative heat losses, and thereby energy consumption. Amongst the types of materials that have been incorporated into electrically driven devices and demonstrated an ability to change their IR reflectivity, carbon nanotubes (CNTs) are amongst the most effective, having a high change in reflectance and excellent cyclability. In this work, we have created electrically-driven devices with tunable reflectance using various types of carbon nanotubes (metallic, semiconducting, mixed), various carbon nanotube geometries (disorganized 2D sheets and ordered vertically-aligned forests), and various device architectures. Through this systematic study, we have elucidated the role that these various factors have on the spectral changes in reflectance and ultimately device performance.<br/><br/>This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.