Cross-conjugated spiro molecules and single-walled carbon nanotubes composite for high-performance organic thermoelectric materials and generators

Abstract

Organic thermoelectric materials have attracted tremendous attention in virtue of their unique advantages including low thermal conductivity, low cost, easy processability and mechanical flexibility. Herein, a series of novel Spiro molecules are designed to be composited with single-walled carbon nanotubes (SWCNT) as p-type thermoelectric materials. An optimum power factor of 218.6 μW m−1 K−2 is acquired from the SFX-2/SWCNT composite at room temperature. The corresponding flexible thermoelectric generator containing 10p-type legs exhibits an output power of 1.0 μW under a temperature gradient of 60 K. The high thermoelectric performance is attributable to the three dimensional cross-conjugated architecture of the Spiro molecules, which promotes interactions with SWCNT leading to high carrier concentration and moderate carrier mobility in the composite film.