Tandem structure of aligned carbon nanotubes on Au and its solar thermal absorption

Parallel, close-arranged carbon nanotubes are promising candidates for sunl ight trapping. A tandem structure was made by synthesizing aligned carbon n anotube arrays on an Au film. With the nanotube length greater than 10 mum, the tandem structure shows an ultra-high absorption in both the visible an d infrared regions. With shorter length (less than 5 mum), infrared reflect ance is enhanced due to the presence of the underlying Au film; however, th e visible absorptance also decreases at the same time. Carbon nanotubes the mselves have no selectivity of solar absorption. They could be used in sola r thermal plants where sunlight is collected with high concentration ratios . (C) 2002 Elsevier Science BN. All rights reserved.