Barrier Energy Engineering\nEnables Efficient Carrier\nTransport of Single-Walled Carbon Nanotube–Small Organic Molecules\nHybrid Thermoelectrics

Understanding the inherent charge carrier transport mechanism\nwithin\ncarbon nanotube–organic hybrid thermoelectric (TE) materials\nis crucial for enhancing their TE performance. Although various carbon\nnanotube–organic hybrid TE materials have been developed, the\ninfluence of the barrier energy on the TE transport mechanism within\nthese hybrids remains elusive. Our study focuses on the engineering\nof barrier energy between single-walled carbon nanotubes (SWCNTs)\nand small organic molecules (SOMs) by modulating the mesomeric effects\nof terminal functional groups on T-shaped SOMs. The minimization of\nbarrier energy in an SWCNTs–<b>BTBIN</b> hybrid to 0.04\neV resulted in a semiconducting-dominant transport character, facilitating\nthe energy filtering of SWCNTs–<b>BTBIN</b>. Consequently,\nSWCNTs–<b>BTBIN</b> achieved a higher Seebeck coefficient\n(65 μV K<sup>–1</sup>) than other hybrids (39–54\nμV K<sup>–1</sup>) having steeper barrier energies (0.30\nand 0.19 eV), enabling the highest power factor (798 μW m<sup>–1</sup> K<sup>–2</sup>) and <i>ZT</i> value\nup to 0.035 at room temperature among SWCNTs–<b>BTBI</b> hybrid series. A TE module consisting of SWCNTs–<b>BTBIN</b> incorporating five-leg TE elements produced an output power exceeding\n0.82 μW, suggesting that integrating barrier energy engineering\nwith analyses of TE transport mechanisms can significantly advance\nthe design of high-performance nanocarbon-based organic hybrid TEs.