Electrochemistry and Photocurrent Response from Vertically-Aligned Chemically-Functionalized Single-Walled Carbon Nanotube Arrays

The unique electronic properties of single walled carbon nanotubes (SWCNTs) can be used to generate a current response from visible light. Vertically aligned single walled carbon nanotube arrays were created on an optically transparent electrode (fluorine doped tin oxide coated glass, FTO) by a self-assembly process using the hydrophobicity of the nanotube side walls and chemical treatment of both the nanotubes and the FTO substrate. The electrode characteristics were explored using electrochemical approaches. The SWCNTs were further functionalized with light absorbing species such as dye or porphyrin. This led to arrays of SWCNTs chemically attached to the substrate that when exposed to visible light exhibited a prompt current response (∼5 μA/ cm², ≤200 ms) and a voltage of ∼33 mV. This photoresponse behavior was investigated by modifying the attachment conditions and also the SWCNT treatment procedures.