Aligning Single‐Walled Carbon Nanotubes By Means Of Langmuir–Blodgett Film Deposition: Optical,Morphological, and Photo‐electrochemical Studies

An alkoxy‐substituted poly(phenylene thiophene) is used in order to suspend single‐walled carbon nanotubes in an organic solvent. The suspension is spread on the air–water interface of a Langmuir trough and the floating film is characterized by means of Brewster angle microscopy and UV‐visible reflection spectroscopy and the compression isotherm is recorded. The polymer/carbon‐nanotube blend is transferred onto different substrates using the Langmuir–Blodgett technique. AFM measurements indicate the formation of globular structures for the samples transferred at low surface‐pressure values and a tubular morphology for high‐pressure‐deposited samples. AFM analysis is repeated on a sample exposed to soft X‐rays for about 5 h and a highly organized structure of bundles of carbon nanotubes rises up. Samples with different numbers of layers are transferred onto ITO substrates by means of the Langmuir–Blodgett method and are tested as photocathodes in a photo‐electrochemical cell. A V_oc of 0.18 V, an I_sc of 85.8 mA, FF of 40.0%, and η of (6.23 × 10^?3)% are obtained.