Presentation on theme: "Discovery and applications of fullerenes Leung Wai Chun F.6B (18) Crystalline form of C 60."— Presentation transcript:
Discovery and applications of fullerenes Leung Wai Chun F.6B (18) Crystalline form of C 60
What is a Fullerene? The third allotropic form of carbon material (after graphite and diamond). A class of closed-cage carbon molecule, C n, characteristically containing 12 pentagons and a variable number of hexagons. <300 carbon atoms buckyballs, include the buckminsterfullerene, C 60. Giant fullerenes include single-shelled or multi- shelled carbon structures, onions, and nanotubes. From left to right: Diamond, graphite, and fullerene. A geodesic dome shares the same geometric structure as a buckminsterfullerene.
Discovery of fullerene In molecular beam experiments, discrete peaks were observed corresponding to molecules with the exact mass of sixty or seventy or more carbon atoms. In 1985, Harold Kroto, James R. Heath, Sean O'Brien, Robert Curl and Richard Smalley discovered C 60, and then the other fullerenes. Kroto, Curl, and Smalley were awarded the 1996 Nobel Prize in Chemistry. Harold Kroto and Richard Smalley
Common types of fullerenes discovered 1. Buckminsterfullerene, C 60 The smallest fullerene with no two pentagons share an edge Named after Richard Buckminster Fuller, a architect who popularized the geodesic dome. Structure of C60, similar to a football
Common types of fullerenes discovered 2. Nanotubes Cylindrical fullerenes Can range from less than a micrometre to several millimetres in length. high tensile strength, electrical conductivity and resistance to heat, relative chemical inactivity Rotating animation of nanotube
Applications of fullerenes 1. Organic Photovoltaics (OPV) Fullerene acts as the n- type semiconductor (electron acceptor) as they are derivitized to increase their solubility. The most commonly used derivative in photovoltaics is C 60, but C 70 has been shown to have a 25% higher power conversion efficiency than C 60.
Applications of fullerenes 2. Antioxidants & Biopharmaceuticals Fullerene can sponge- up and neutralize >20 free radicals per fullerene molecule. hold great promise in health and personal care applications where prevention of oxidative cell damage or death is desirable. A skin care cream based on C 60
Other applications of fullerenes 1. Catalysts Marked ability to accept and to transfer hydrogen atoms; hydrogenation and hydrodealkylations. Inhibits coking reactions. 2. Water purification & bio-hazard protection Singlet oxygen catalysis of organics with fullerene C Portable power Proton exchange membranes for fuel cells 4. Vehicles Enhanced durability 5. Medical MRI agents