Carbon nanostructures/tin (IV) oxide systems and transparent electrode application

Abstract

Interesting electronic properties of sp2 hybridized carbon materials has been attracting an enormous number of researchers around the globe. Some of the efforts, for more than a decade, have been in attempting to replace the conventional transparent electrode indium tin oxide (ITO) with carbon nanostructures, namely carbon nanotube and graphene. In this thesis, carbon nanostructures and metal oxide hybrid system is studied in an attempt to reduce the resistance of carbon-based transparent conducting films. It is expected that charge transfer doping in carbon nanostructures will take place upon contact with metal oxide due to the difference in the work function. Focusing primarily on single-walled carbon nanotube network, the percolation theory suggested by Hu and colleagues was used to calculate a figure of merit, DC to optical conductivity ratio, from optical transmittance and sheet resistance. Among the metal alkoxides tested, tin isopropoxide was demonstrated to be the best dopant for carbon nanostructures, and carbon nanotube film and tin (IV) oxide system was studied with electrical measurement and near-IR absorption and Raman spectroscopies. The concentration of 0.5 to 2% w/v of tin isopropoxide solution in isopropanol (TIP) was determined to optimize transmittance and conductance of carbon nanotube and graphene films. A proof-of-concept thin film diode was fabricated with this hybrid system, which exhibited successful rectifying behavior.