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This study introduces the synthesis of a hybrid thermoelectric material with enhanced conductivity and a high Seebeck coefficient, leveraging the properties of Te nanowires (NWs) and the conductive polymer PEDOT:PSS. Te NWs were synthesized using the galvanic displacement reaction. To further enhance conductivity, Ag-Te NWs were synthesized under optimized conditions via the Ag topotactic reaction, achieving desired results within 7 min using ethylene glycol and AgNO3. This hybrid material exhibited an electrical conductivity of 463 S/cm, a Seebeck coefficient of 69.5 μV/K at 300 K, and a power factor of 260 μW/mK2. These metrics surpassed those of conventional Te/PEDOT:PSS hybrids by a factor of 3.6, highlighting the superior performance of our approach. This study represents a significant advancement in thermoelectric materials, improving both conductivity and efficiency. [ABSTRACT FROM AUTHOR]

Bi x Sb 2-x Te y films with controlled compositions were synthesized by a simple and cost-effective electrodeposition technique followed by post-annealing, for thermoelectric applications. Tailoring the chemical composition of ternary Bi x Sb 2-x Te y materials is critical to adjust the carrier concentration and carrier type, which are crucial to determine their thermoelectric performance. Herein, the composition of electrodeposited Bi x Sb 2-x Te y film was simply tailored by controlling the [Sb]/[Bi] ratio in the electrolytes while maintaining their dense and uniform morphology. Crystallographic properties of the Bi x Sb 2-x Te y films, such as crystallinity and grain size changes, were confirmed by X-ray diffraction. Room-temperature measurements of electrical conductivity, Hall mobility, and carrier concentration revealed that the substitution of Bi with Sb decreased the carrier concentration, and increased the mobility. The Seebeck coefficient of the ternary Bi x Sb 2-x Te y films transitioned between p- and n-type characteristics with an increase in the Bi content. Moreover, the mobility-dependent electrical conductivity of the Bi 10 Sb 30 Te 60 film resulted in a high Seebeck coefficient owing to decreased carrier concentration of the film, leading to a power factor (PF) of ∼490 μW/m K 2 . This is more than 10 times higher than the PF values of binary nanocrystalline Sb 2 Te 3 films. [ABSTRACT FROM AUTHOR]

The Te-embedded PbTe nanocrystallline thick films (i.e., 50 µm) were electrodeposited, where the fraction and average grain size of PbTe and Te phases were tuned by adjusting the applied potential followed by post thermal treatment. The crystal grain boundary and Te nano-inclusion in the films played critical roles in their thermoelectric properties. The Te-embedded PbTe thick film with the average grain size of around 100 nm showed lower energy barrier height (EB = 0.023 eV) than thick films with the average grain size of a few tens of nm (EB = 0.11). Although decrease in the energy barrier reduced the Seebeck coefficient, however, it enhanced the electrical conductivity, which resulted in an increase in power factor (PF). The highest power factor was 183 μw K−2 cm−1, achieved at the energy barrier of 0.023 eV. [ABSTRACT FROM AUTHOR]

A novel method for fabrication of a thermochemical hydrogen (TCH) gas sensor composed of platinum (Pt)-decorated graphene sheets and a thermoelectric (TE) polymer nanocomposite was investigated. The hydrogen sensing characterization for the device included gas response, response time (T 90), recovery time (D 10), and reliability testing, which were systematically conducted at room temperature with a relative humidity of 55%. Here, the Pt-decorated graphene sheets act as both an effective hydrogen oxidation surface and a heat-transfer TE polymer nanocomposite having low thermal conductivity. This property plays an important role in generating output voltage signal with a temperature difference between the top and bottom surfaces of the nanocomposite. As a result, our TCH gas sensor can detect the range of hydrogen from 100 ppm to percentage level with good linearity. The best response and recovery time revealed for the optimized TCH gas sensor were 23 s and 17 s under 1000 ppm H 2 /air, respectively. This type of sensor can provide an important component for fabricating thermoelectric-based gas sensors with favorable gas sensing performance. • A novel-type of TE composite-based hydrogen gas sensor was fabricated. • Gas response of the sensor was considerably linear at low- and high concentrations. • The sensor has a detection limit of 100 ppm with high signal to noise ratio. • The response/recovery times were 23 s and 17 s under 1000 ppm H 2 /air, respectively. [ABSTRACT FROM AUTHOR]

Bismuth telluride (Bi 2 Te 3 ) thin films were electrodeposited at room temperature from nitric baths in the presence of a surfactant, cetyltrimethylammonium bromide (CTAB). Nearly stoichiometric Bi 2 Te 3 thin films were obtained from electrolytes containing 7.5 mM Bi(NO 3 ) 3 . The surface morphology and mechanical properties of the electrodeposited thin film were improved by the addition of CTAB to the electrolyte, while the electrical and thermoelectric properties were preserved. Post-deposition annealing in a reducing environment did not improve the electrical and thermoelectric properties, possibly because the change in the microstructure of the Bi 2 Te 3 thin film was too small. [ABSTRACT FROM AUTHOR]