Production of Fullerenes with Concentrated Solar Flux

Research at the National Renewable Energy Laboratory (NREL) has demonstrated that fullerenes can be produced using highly concentrated sunlight from a solar furnace. Since they were first synthesized in 1989, fullerenes have been the subject of intense research. They show considerable commercial potential in advanced materials and have potential applications that include semiconductors,superconductors, high-performance metals, and medical technologies. The most common fullerene is C60, which is a molecule with a geometry resembling a soccer ball. Graphite vaporization methods such as pulsed-laser vaporization, resistive heating, and carbon arc have been used. to produce fullerenes. None of these, however, seems capable of producing fullerenes economically on a large scale. Theuse of concentrated sunlight may help avoid the scale-up limitations inherent in more established production processes. Recently, researchers at NREL made fullerenes in NREL's 10 kW High Flux Solar Furnace (HFSF) with a vacuum reaction chamber designed to deliver a solar flux of 1200 W/ cm2 to a graphite pellet Analysis of the resulting carbon soot by mass spectrometry and high-pressure liquidchromatography confirmed the existence of fullerenes. These results are very encouraging and we are optimistic that concentrated solar flux can provide a means for large-scale, economical production of fullerenes. This paper presents our method, experimental apparatus, and results of fullerene production research performed with the HFSF.