Conjugated Polymers and Carbon Nanotubes for Optoelectronic Applications Liming Dai Department of Polymer Engineering College of Polymer Science and Polymer Engineering The University of Akron, Akron, OH In close collaboration with Richard A. Vaia AFRL Materials and Manufacturing Directorate Bldg 654, 2941 P St. Wright-Patterson AFB, OH Collaborative Center for Polymer Photonics Workshop at Akron, April 22-23, 2004

Important Discoveries 1977 Conducting Polymer by Heeger, MacDiarmid, Shirakawa 1985 Fullerene C60 Curl, Kroto, Smalley 1990 Conjugated Polymer LEDs by Friend et al. + n e.g Carbon Nanotube by Iijima

Requirements for Polymers to be Electrically Conducting Just like metals have high conductivity due to the free movement of electrons through their structure, for polymeric systems to be electronically conductive they must possess: a) Charge carriers (Doping) b) An orbit that allows the charge carriers to move (Conjugation) n-doping p-doping

Iodine-Induced Conjugation of Polydienes Dai, L. et al, Macromolecules, 1994, 27, 6728.

Micropatterning of Conducting Rubbers Dai, L. et al., Macromolecules 1996, 29, 282. (a) (b)

The Principle for Polymer Light-Emitting Diodes

Colour Tunability of the Light-Emitting Polymers

Patterned and Multilayered Light Emissions

Confined Space for Colour Tuning B. Winkler et al., J. Mater. Sci. Lett. 1999, 18, 1539.

Heeger, et al, Science 1995, 270, MEH-PPV-C60 blends Conducting Polymer Plastic Solar Cells

Iodine-Induced Conjugation of C 60 -Grafted Polydienes Dai, L. et al., J. Phys. Chem. 1995, 99,

Sulfonated C 60 /Dendrimer - Doped Polyaniline Dai, L. et al, J. Phys. Chem. 1998, 102, 4049.

Optoelectronic Properties of the Sulfonated C 60 -Doped Polyaniline Film Dai, L, et al., J. Phys Chem. 1998, 102, 4049

Optical Limiting by C 60 -Ag Nanocomposites Sun N., et al., Chem. Phys. Lett. 2002, 356, 175. Optical limiting responses to 8ns, 532 nm optical pulses, HDTC60–Ag (square), DT–Ag (circle), and HDTC60 (triangle).

Polyaniline Nanotubes Qiu, et al. Macromolecules 2001, 34, 675. PANI-(CNT- OSO 3 H) PANI-(C 60 -OSO 3 H) Wei, et al. Adv. Mater. 2003, 15, 136.

Conducting Polymer Micro-/nano-structures Bajpai, et al. Adv. Funct. Mater. 2004, 14, 145.

Potential Applications of Conducting Polymer Micro-/nano-structures

Carbon Nanotube Electron-Emitting Displays Courtesy of Y. Saito

Pyrolytic Growth of Aligned Carbon Nanotubes from Metal-Organic Complex Molecules Huang, et al., J. Phys. Chem. B 1999, 103, 4223.

Huang & Dai J. Nanoparticle Res. 2002, 4, 145. The Growth Process for Aligned Carbon Nanotubes