Single-Wall Carbon Nanotubes Chemically Modified with Cysteamine and Their Application in Polymer Solar Cells: Influence of the Chemical Modification on Device Performance

In order to improve the dispersion of single-wall carbon nanotubes in a matrix of poly(3-hexylthiophene), this paper reports the modification of single-wall carbon nanotubes with COOH groups followed by reaction with cysteamine that introduced thiol groups along the tubes. The resulting modified single-wall carbon nanotubes were characterized by high resolution transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and Raman spectroscopy. The modified carbon nanotubes were applied, in combination with poly(3-hexylthiophene), in a bulk heterojunction solar cell. After passing through a post-treatment process to obtain debundled modified single-wall carbon nanotubes, solar cells with improved performance were obtained. After the treatment sequence, both the open circuit voltage and short-circuit current increased in comparison to the non-treated modified single-wall carbon nanotubes polymer solar cells.