Flexible organic−inorganic hybrids are promising thermoelectric materials to recycle waste heat in versatile formats. However, current organic/inorganic hybrids suffer from inferior thermoelectric properties due to aggregate nanostructures. Here we demonstrate flexible organic−inorganic hybrids where size-tunable Bi2Te3 nanoparticles are discontinuously monodispersed in the continuous conductive polymer phase, completely distinct from traditional bi-continuous hybrids. Periodic nanofillers significantly scatter phonons while continuous conducting polymer phase provides favored electronic transport, resulting in ultrahigh power factor of ~1350 μW m−1 K−2 and ultralow in-plane thermal conductivity of ~0.7 W m−1 K−1. Consequently, figure-of-merit (ZT) of 0.58 is obtained at room temperature, outperforming all reported organic materials and organic−inorganic hybrids. Thermoelectric properties of as-fabricated hybrids show negligible change for bending 100 cycles, indicating superior mechanical flexibility. These findings provide significant scientific foundation for shaping flexible thermoelectric functionality via synergistic integration of organic and inorganic components.
Wearable thermoelectric devices show promise to generate electricity in a ubiquitous, unintermittent and noiseless way for on-body applications. Three-dimensional thermoelectric textiles (TETs) outperform other types in smart textiles owing to their out-of-plane thermoelectric generation and good structural conformability with fabrics. Yet, there has been a lack of efficient strategies in scalable manufacture of TETs for sustainably powering electronics. Here, we fabricate organic spacer fabric shaped TETs by sewing carbon nanotube yarn based segmented thermoelectric textiles on a large scale. Combining finite element analysis with experimental evaluation, we elucidate that the fabric structure significantly influences the power generation. The optimally designed TET with good wearability and stability shows a high output power density of 51.5 mW m−2 and a high specific power of 171.7 μW (g K)−1 at ΔT = 47.5 K. The promising on-body application of the TET in directly and continuously powering electronics for healthcare and environmental monitoring is fully demonstrated. This work will broaden the research vision and provide new routines for developing high-performance and large-scale TETs toward practical applications.
4 November 2020 in Advanced Composites and Hybrid Materials
Freestanding poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires were synthesized by template-confined in situ polymerization, and then integrated into polystyrene sulfonate (PSS)-doped PEDOT and tosylate-doped PEDOT hosts, respectively. The hybrid morphologies were characterized by atomic force microscopy, indicating the homogeneous dispersion of PEDOT nanowires. The thermoelectric properties of the resultant hybrids were measured, and the power factor was found to be enhanced by 9-fold in comparison with PEDOT:PSS mixed with 5 vol% dimethyl sulfoxide while the low thermal conductivity was still maintained. Such a significant improvement could be attributed to the synergistic effects of interfacial energy filtering, component contributions, and changes of carrier concentrations in the host materials. Upon addition of 0.2 wt% PEDOT nanowires, the resultant composites demonstrated a power factor as high as 446.6 μW m−1 K−2 and the thermoelectric figure of merit could reach 0.44 at room temperature. The thermoelectric devices were investigated by using the PEDOT nanowire/PEDOT hybrid as a p-type leg and nitrogen-doped graphene as an n-type leg. The normalized power output was as high as ∼0.5 mW m−2 for a temperature gradient of ΔT = 10.1 °C, indicating great potential for practical applications. These findings open up a new route towards high-performance organic thermoelectric materials and devices.