Electrodeposited polyaniline/multi-walled carbon nanotube composites for solar cell applications

Polyaniline (PANI)/multi-walled carbon nanotube (MWNT) composite films were fabricated by an electrochemical polymerization of aniline with airbrushed MWNTs on ITO substrates. Structural, optical, and electrical properties of the films were studied by Raman, FTIR, optical absorption, and resistivity measurements. The incorporation of MWNTs in PANI was found to effectively increase the film conductivity with a percolation threshold of 5% of nanotubes in the composite. Organic-inorganic hybrid solar cells based on the composite films of different MWNT concentrations and TiO2 nanocrystals were investigated. It was found that the solar cell performance strongly depends on the conductivity of the composite films, which can be tuned by adjusting nanotube concentration. A higher conductivity resulted in a better cell performance, resulting from an efficient charge collection. This study indicates that PANI/MWNT composite films with optimized conductivity are potentially useful for low-cost hybrid solar cell applications. (C) 2012 Elsevier B.V. All rights reserved.