12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone

Tuning Carbon Nanotubes for Application in Photovoltaic Devices

13 Jul 2011, 12:30


Oral Presentation Track A - Condensed Matter Physics and Material Science CMPMS1


Mr George Bepete (University of the Witwatersrand)


Control of diameter, length and level of nitrogen doping in synthesis of nitrogen doped carbon nanotubes (N-CNTs) can be achieved by careful selection of catalyst, precursor mixture and chemical vapour deposition (CVD) synthesis temperature. Solutions of ethanol and acetonitrile (20% acetonitrile) were pyrolysed over a Fe/Al/MgO catalyst in a CVD reactor at temperatures from 700 OC to 1000 OC. The products were characterised by TGA, TEM and Raman spectroscopy. N-CNTs with well graphitised morphology, small diameter, and narrow diameter distribution were obtained at CVD temperatures from 850 OC to 900 OC. Below 800 OC the N-CNTs with large seized diameters were formed and above 900 OC the product yield became very low and the carbon nanotubes were malformed with wide diameter distribution. By pyrolysing precursor mixtures of acetonitrile and alcohols (methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol and octanol) we found out that short, 500 nm in length N-CNTs were obtained by the pyrolysis of long chain alcohols, (heptanol and octanol) and acetonitrile solution whilst longer N-CNTs were formed from pyrolysis of earlier alcohols (methanol, ethanol and propanol). Short and thin carbon nanotubes can be useful in carbon based nanoelectronics and photovoltaic devices since there is less entanglement of N-CNTs which will result in good dispersion of carbon nanotubes in solutions and polymer matrix. Preliminary results of the devices made from N-CNTs will be presented.

Consider for a student <br> &nbsp; award (Yes / No)? Yes
Level (Hons, MSc, <br> &nbsp; PhD, other)? PhD
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)? Yes

Primary author

Mr George Bepete (University of the Witwatersrand)


Dr Daniel Wamwangi (University of the Witwatersrand) Mr Lesias Kotane (University of the Witwatersrand) Prof. Neil Coville (University of the Witwatersrand) Dr Zivayi Chiguvare (University of the Witwatersrand)

Presentation Materials