ICT2014 Abstracts

Flexible organic thermoelectric modules made of both p- and n-type single wall carbon nanotubes were developed to generate high voltage and power enough to operate biosensors. In order to prepare n-type films, nanotubes were functionalized by both diethylenetriamine (DETA) and polyethyleneimine (PEI), and subsequently further reduced by using NaBH₄. The thermopower and electrical conductivity of optimized n-type nanotubes were measured to be -86 µV/K and 5,200 S/m, respectively. The p-type nanotube samples have a thermopower and electrical conductivity value of +100 µV/K and 11,000 S/m, respectively. Electronic band structures with the Fermi level and carrier mobilities of the CNTs were experimentally investigated, which have elucidated the carrier type and relatively large thermopower values. The as-synthesized 72 p- and n-type pairs were assembled by stacking them alternatively to complete the power generation module. The Seebeck voltage of the thermoelectric module was measured to be 9.3 mV/K leading to a 465 mV output at a temperature gradient, ΔT = 49 K, which are significantly larger than other polymer based organic composites. A glucose sensor was operated by using 1.8 µW from the thermoelectric module at ΔT = 32 K. We demonstrated that flexible organic thermoelectric devices are promising for portable and self-powered sensors.