Structural and Thermoelectric Properties of Optically Transparent Thin Films Based on Single-Walled Carbon Nanotubes

Thin films have been produced via a spray method from commercially available single-walled carbon nanotubes (SWCNTs). A SWCNT film thickness has ranged from 10 to 80 nm. The SWCNT diameter has accepted values of 1.6-1.8 nm. The existence of SWCNTs longer than 10 m is established. The optimal thickness of a SWCNT thin film is found to be 15 nm at which the transmittance exceeds 85%. The specific resistance of SWCNT thin films goes from 1.5 x 10(-3) to 3 x 10(-3) Ohm cm at room temperature. The pioneering study of the temperature dependences of the Seebeck coefficient and surface resistance is performed for this type of SWCNT. A surface resistance is found to increase with rising temperature. Furthermore, the Seebeck coefficient of SWCNT thin films weakly depends on temperature. Its value for all samples is evaluated to be 40 V/K. According to the sign of the Seebeck coefficient, thin films exhibit hole-type conductivity. Moreover, the power factor of a 15-nm thin SWCNT-film decreases with a temperature increase to 140?C from the value of approximately 120 to 60 W m(-1) K-2. A further rise in temperature has led to a gain in the power factor.