Abstract
Single-walled carbon nanotubes (SWCNTs) incorporated with π-conjugated polymers, have proven to be an effective approach in the production of advanced thermoelectric composites. However, the studied polymers are mainly limited to scanty conventional conductive polymers, and their performances still remain to be improved. Herein, a new planar moiety of platinum acetylide in the π-conjugated system is introduced to enhance the intermolecular interaction with the SWCNTs via π–π and d–π interactions, which is crucial in regulating the thermoelectric performances of SWCNT-based composites. As expected, SWCNT composites based on the platinum acetylides embedded polymers displayed a higher power factor (130.7 ± 3.8 μW·m−1·K−2) at ambient temperature than those without platinum acetylides (59.5 ± 0.7 μW·m−1·K−2) under the same conditions. Moreover, the strong interactions between the platinum acetylide-based polymers and the SWCNTs are confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements.
Highlights
Thermoelectric (TE) materials, which can directly convert thermal energy into electrical energy via the mobility of solid internal carriers, have demonstrated a great potential in both power generation and solid-state cooling or heating [1,2,3,4]
The platinum acetylides embedded polymer of P(TBT-Pt) was synthesized by the CuI/Pd(PPh3 )4 -catalyzed coupling reaction, in the presence of terminal alkynes precursor and trans-[PtCl2 (PBu3 )], in a good yield over 97%. Both of the two polymers were well characterized by 1 H NMR spectroscopy and gel permeation chromatography (GPC) analysis (Figure S1)
In order to exclude the influence of the degree of polymerization (DP) on the thermoelectric properties, both of P(TBT-Pt) and P(TBT) were deliberately synthesized with almost the same DP; i.e., DP = 22 for P(TBT-Pt), and DP = 21 for P(TBT) (Figure S1)
Summary
Thermoelectric (TE) materials, which can directly convert thermal energy into electrical energy via the mobility of solid internal carriers, have demonstrated a great potential in both power generation and solid-state cooling or heating [1,2,3,4]. It still remains a massive challenge to optimize the ZT values in a unitary system due to the interactions between the σ, S and κ, i.e., since in most cases the increase of σ relies on the enhancement of the carrier concentration, which may result in diminution of S or raising of κ [13,14,15] To alleviate this issue, a composite system by incorporating two or more components may provide a valid approach to address this concern [16,17,18]. Π-conjugated polymers are regarded as favorable organic TE materials due to the potentially high S and low κ, but the intrinsically low σ is far from satisfactory [19,20]; on the other hand, single-walled carbon nanotubes (SWCNTs) have prominent high σ and mechanical robustness, but low S and high κ, which render them as perfect counterparts to organic TE materials.
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