The influence of incorporating organic molecules or inorganic nanoparticles on the optical and electrical properties of carbon nanotube films

Organic molecules and inorganic nanoparticles were incorporated into transparent and conductive single- or double-wall carbon nanotube (SWNT or DWNT) films, and their electrical and optical properties were measured. When organic tetrafluoro-tetracyanoquinodimethane (F₄TCNQ) molecules were incorporated into the nanotube films, sheet resistance was reduced to ∼50% of those from the pristine SWNT and DWNT films. Larger improvements were observed with Au nanoparticle decoration or HNO₃/SOCl₂ dipping processes. The sheet resistances were measured to be at 75% of transmittance for HNO₃/SOCl₂-treated DWNT films and at 77% for Au-incorporated DWNT films, making their electrical conductivities 200%-300% better than those of the pristine DWNT films. It was observed that DWNTs have better electrical/optical performance than SWNTs. The relative influence of various dopants, F₄TCNQ, Au, and HNO₃/SOCl₂ as well as microwave irradiation on the optical and electrical properties was identified by using Raman and UV-vis-NIR spectra.