In this study, we introduce the fabrication process of a highly efficient fully printed all-carbon Organic Thermoelectric Generator (OTEG) free of metallic junctions, with outstanding flexibility and exceptional power output, which can be conveniently and rapidly prepared through ink dispensing/printing processes of non-toxic and low-cost aqueous CNT inks with a mask-assisted specified circuit architecture. The optimal produced p-type and n-type films exhibit ultrahigh power factors of 308 μW/mK 2 and 258 μW/mK 2 respectively at ΔΤ=150K (THOT=175°C) and outstanding stability in air without encapsulation, providing the OTEG device the ability to operate at high temperatures up to 200°C at ambient conditions (1 atm, relative humidity: 50±5% RH).We have successfully design and fabricate the flexible thermoelectric modules with superior thermoelectric properties of p-type and n-type SWCNT films resulting in exceptionally high performance. The novel-design OTEG exhibits outstanding flexibility and stability with attained TE values among the highest ever reported in the field of organic thermoelectrics, i.e. open-circuit voltage VOC= 1.05 V and short-circuit current ISC= 1.30 mA at ΔT= 150 K (THOT=175°C) with an internal resistance of RTEG= 806 Ω, generating 342 μW power output. It is also worth noting the remarkable power factors of 145 μW/mK 2 and 127 μW/mK 2 for the p-type and n-type films respectively at room temperature. The fabricated device is highly scalable, providing opportunities for printable large-scale manufacturing/industrial production of highly efficient flexible OTEGs. TOC GRAPHICSGraphical abstract. Schematic illustration of the all-carbon printed and flexible SWCNT-based organic thermoelectric generator

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This experimental study is associated with the modification of glass fibers with efficient, organic, functional, thermoelectrically enabled coatings. The thermoelectric (TE) behavior of the coated glass fiber tows with either inherent p semiconductor type single wall carbon nanotubes (SWCNTs) or the n-type molecular doped SWCNTs were examined within epoxy resin matrix in detail. The corresponding morphological, thermogravimetric, spectroscopic, and thermoelectric measurements were assessed in order to characterize the produced functional interphases. For the p-type model composites, the Seebeck coefficient was +16.2 μV/K which corresponds to a power factor of 0.02 μW/m∙K2 and for the n-type −28.4 μV/K which corresponds to power factor of 0.12 μW/m∙K2. The p–n junction between the model composites allowed for the fabrication of a single pair thermoelectric element generator (TEG) demonstrator. Furthermore, the stress transfer at the interphase of the coated glass fibers was studied by tow pull-out tests. The reference glass fiber tows presented the highest interfacial shear stress (IFSS) of 42.8 MPa in comparison to the p- and n-type SWCNT coated GF model composites that exhibited reduced IFSS values by 10.1% and 28.1%, respectively.

This study demonstrates for the first time a structural glass fiber-reinforced polymer (GFRP) composite laminate with efficient thermal energy harvesting properties as a thermoelectric generator (TEG). This TEG laminate was fabricated by stacking unidirectional glass fiber (GF) laminae coated with p- and n-type single-wall carbon nanotube (SWCNT) inks via a blade coating technique. According to their thermoelectric (TE) response, the p- and n-type GF-SWCNT fabrics exhibited Seebeck coefficients of +23 and −29 μV/K with 60 and 118 μW/m·K2 power factor values, respectively. The in-series p–n interconnection of the TE-enabled GF-SWCNT fabrics and their subsequent impregnation with epoxy resin effectively generated an electrical power output of 2.2 μW directly from a 16-ply GFRP TEG laminate exposed to a temperature difference (ΔT) of 100 K. Both experimental and modeling work validated the TE performance. The structural integrity of the multifunctional GFRP was tested by three-point bending coupled with online monitoring of the steady-state TE current (I sc) at a ΔΤ of 80 K. I sc was found to closely follow all transitions and discontinuities related to structural damage in the stress/strain curve, thus showing its potential to serve the functions of power generation and damage monitoring.