The dispersions of semiconducting (sc-) and metallic (m-) SWCNTs with purity more than 98 and 86%, correspondingly,
were obtained by using the aqueous two-phase extraction method. The unseparated (un-) SWCNTs
contained ~3/4 of semiconducting and ~1/4 of metallic nanotubes. Thin films based on unseparated, semiconducting
and metallic SWCNTs were prepared by vacuum filtration method. An Atomic Force Microscopy
(AFM) and a Transmission Electronic Microscopy (TEM) were used to investigate the thin film microstructure.
The thin SWCNT film transmittance was measured in the wavelength range of 300–1500 nm. Thermoelectric
properties were carried out in the temperature range up to 200 °C. The largest Seebeck coefficient was observed
for thin films based on semiconducting SWCNTs. The maximum value was 98 μV/K under the temperature of
170 °C. The lowest resistivity was 7.5·10−4·Ohm·cm at room temperature for thin un-SWCNT films. The power
factor for m-SWCNT and un-SWCNT films was 47 and 213 μWm−1 K−2, correspondingly, at room temperature
and 74 and 54 μWm−1 K−2 at 200 °C, respectively. For a thin sc-SWCNT film the maximum power factor was
2.8 μWm−1 K−2 at 160 °C. The un-SWCNT film thermal conductivity coefficient was 5.63 and 3.64Wm−1 K−1
and a thermoelectric figure of merit was 0.011 and 0.016 at temperatures of 23 and 50 °C, respectively.
Источник:Physica E: Low-Dimensional Systems and Nanostructures
Ключевые слова:Single-wall carbon nanotubes, Aqueous two-phase extraction, Semiconducting and metallic SWNTs, Thin SWNT films, Thermoelectric properties, Thermoelectric figure of merit, Институт цветных металлов и материаловедения, Институт инженерной физики и радиоэлектроники, ИЦМиМ, ИИФиРЭ, сфу