F.6 Chemistry Internet Searching Activity 2

1. Discovery and Application of Fullerenes By Chor Tak Lam (1) F.6B F.6 ChemistryInternet Searching Activity 2

2. The discovery of fullereces A Gallery of Carbonfrom left, Diamond, Graphite, Carbon Chain C60 (upper row), C70 and Nanotube (lower row)

3. The experiments that led to the discovery of C60 were aimed at simulating in the laboratory the conditions under which carbon nucleates in the atmosphere of a cool carbon-rich red giant star. However, even more significant was the unexpected discovery of C60 in1985 by Kroto • The 1996 Nobel Prize for Chemistry has been won by Harold W. Kroto, Richard E. Smalley and Robert F. Curl Jr. for this great discovery.

4. In 1990, physicists W. Krätschmer and D. R. Huffman had successfully produced isolable quantities of C60 for the first time. This showed there really were C60 in our world. Curl Kroto Smalley Huffman

5. Structure of C60, the best known fullerence 12Pentagonal ring 20Hexagonal ring

6. ApplicationsOrganic Photovoltaics (OPV) Currently, the record efficiency for a bulk heterojunction polymer solar cell is a fullerene/polymer blend. The fullerene acts as the n-type semiconductor (electron acceptor). The n-type is used in conjunction with a p-type polymer (electron donor), typically a polythiophene. They are blended and cast as the active layer to create what is known as a bulk heterojunction. The most commonly used derivative in photovoltaics is C60, but C70 has been shown to have a 25% higher power conversion efficiency than C60

7. The performance of polymer transistors (Organic Field Effect Transistors (OFETS)) and photodetectors has also been increasing, in part due to a great deal of synergy between OFETS and OPVs. The leading OFETS use the n-type semiconducting properties of fullerenes based on C60, C70 along with C84. Fullerene OFETS fabricated with C84 show greater mobility than C60 or C70 and exhibit greater stability. While more work is needed, the world of polymer electronics is opening up for both fullerenes and single-walled carbon nanotubes. The model complexes generated via the program DOCK3 suggest that C60 derivatives fit snugly in the active site, thereby removing 298 A2 of primarily nonpolar surface from solvent exposure and driving ligand/protein association. The prediction that these compounds should bind to the active site and thereby act as inhibitors has been borne out by the experimental evidence. Polymer Electronics Inhibition of HIV-1 protease (HIVP)

8. Application of nanotube • The strength and flexibility of carbon nanotubes makes them of potential use in controlling other nanoscale structures • e.g. clothes and sports gear to combat jackets and space elevators. However, the space elevatorswill require further efforts in refining carbon nanotube technology, as the practical tensile • strength of carbon nanotubes can still be greatly improved. an unusual current conduction mechanism make nanotube ideal components of electrical circuits. • Nanotube based transistors have been made that operate at room temperature and that are capable of digital switching using a single electron. • implemented in nanoelectromechanical systems, including mechanical memory elements (NRAM being developed by Nantero Inc.) and nanoscale electric motors

9. Reference websites • http://en.wikipedia.org/wiki/Carbon_nanotube • http://www.chemistry.wustl.edu/%7Eedudev/Fullerene/discovery.html#index • http://www.onk.ns.ac.yu/Archive/Vol5/v5n3p159.htm • http://www.seed.slb.com/en/scictr/watch/fullerenes/smallest.htm Other websites • http://cccmkc.edu.hk/~sbj-chemistry/98-99%20S.6%20Project/Buckminsterfullerene/Content.htm • http://nanotube.msu.edu/ • http://library.kmitnb.ac.th/article/atc47/14410.pdf