High-Performance N-Type Carbon Nanotube Composites: Improved Power Factor by Optimizing the Acridine Scaffold and Tailoring the Side Chains

Abstract

Single-walled carbon nanotubes (SWCNTs)/organic small molecules (OSMs) are promising candidates for application in thermoelectric (TE) modules; however, the development of n-type SWCNT/OSMs with high performance is lagging behind. Only a few structure−activity relationships of OSMs on SWCNT composites have been reported. Recently, we find that the n-type acridone/SWCNT composites display high power factor (PF) values at high temperature but suffer from low PFs at room temperature. Here, the performance of SWCNT composites containing an acridine derivative (AD) as well as its analogues with different counterions (Cl − , SO 4 2− and F − ) and lengths of alkyl chains (ADLA1−2 and ADLA4−5) is reported. Among the composites, SWCNT/ADLA4 with no counterions exhibits the highest PF value of 195.2 μW m −1 K −2 at room temperature, which is 4.9 times higher than that of SWCNT/ADTAd (39.8 μW m −1 K −2 ), indicating that the acridine scaffold and the lengths of alkyl chains contribute to the dramatic changes in the TE performance. In addition, SWCNT/ADLA4 exhibits high PF values at all the temperatures we investigate, which range from 154.7 to 230.7 μW m −1 K −2 . Furthermore, a TE device consisting of five pairs of p (the pristine SWCNTs)−n (SWCNT/ADLA4) junctions is assembled, generating a relatively high open-circuit voltage (41.7 mV) and an output power of 1.88 μW at a temperature difference of 74.8 K. Our results suggest that structural modifications might be an effective way to advance the development of TE materials.

Pseudo in situ construction of high-performance thermoelectric composites with a dioxothiopyrone-based D–A polymer coating on SWCNTs

“…5f), respectively, which may be explained for the enhanced electronic cloud density on the electronegative O atoms of carbonyl and sulfone resulting from the electron transfer from the SWCNT system to the polymer backbone. [42][43][44][45] These results are exactly in concert with those of Raman spectra and simulated calculations, revealing the strong interfacial interactions between the polymer and SWCNTs.…”

“…This indicates that the effective electron transfer occurs from SWCNTs to the polymer, namely that the polymer acts as an acceptor to attract electrons from the SWCNT backbone. [42][43][44] And, the more distinct change in the binding energy for the in situ prepared composite reveals the more effective interaction between SWCNTs and polymer. Considering only two characteristic species of oxygen atoms in the polymer, the binding energies of O 1s for the polymer were also used for clarifying the charge transfer between the polymer and SWCNTs.…”

Synergistic optimization of thermoelectric performance in cementitious composites by lithium carbonate and carbon nanotubes

“…For example, ferromagnetic metal nanoparticles or nanowires filled in carbon nanotubes have greatly improved oxidation resistance 44,45 and are used in many fields such as high-density data storage, 46 biomedical field, 47 and electromagnetic absorption shielding, 48 even in new energy fields. [49][50][51] In this study, carbon nanotubes were used as a nano-containers to fill metal lithium salts by capillary forces. The cement-based composites mixed with lithium carbonate modified multi-walled carbon nanotubes have lower conductivity and higher Seebeck coefficient, and achieved higher power factor, comparing with the cement-based composite material mixed with pure carbon nanotubes.…”

Origin of N-Type Thermoelectric Properties in Single-Wall Carbon Nanotube Films With Anionic Surfactants Investigated by Experimental Analyses and First-Principles Calculations

“…Owing to defects, pristine SWCNTs exhibit n-type properties, which immediately change to p-type ones when the SWCNTs are exposed to air 25 . Under these circumstances, many researchers have attempted to fabricate SWCNTs with n-type properties using various experimental approaches 26,27,28,29,30 . Nakashima et al prepared air-stable n-type SWCNTs doped with benzimidazole derivatives and discussed their air-stable mechanism 31 .…”