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Flexible polymer thermoelectric thin film attracts wide attentions because it is compatible with the wearable electronics and e-skin. Herein, we reported an enhanced thermoelectric power factor of PEDOT:PSS from around 1 μW m−1 K−2 to 117 μW m−1 K−2 and high substrate-free strain of 20% through synergistically tuning the ordering structure and the oxidation state. An ionic liquid (EMImTCM) was used to decouple the ionic interaction between PEDOT and PSS, rearranging the morphology of structure that significantly benefit the mechanical flexibility and the electrical conductivity. The addition of L-ascorbic acid was confirmed as effective dedoping additive of PEDOT polymer that changed the oxidation state and hence boosted the thermoelectric power factor without notable sacrifice of the mechanical flexibility. Moreover, the electrical conductivity of the corresponding film maintained electrically stable (ΔR/R0

The polymerization of solid-state small organic molecules generally involving no less three units has been demonstrated to be an important prospect in the field of organic electrons. Presently, owi...

Amorphization using impurity doping is a promising approach to improve the thermoelectric properties of tin-doped indium oxide (ITO) thin films. However, an abnormal phenomenon has been observed where an excessive concentration of doped atoms increases the lattice thermal conductivity (κl). To elucidate this paradox, we propose two hypotheses: (1) metal hydroxide formation due to the low bond enthalpy energy of O and metal atoms and (2) localized vibration due to excessive impurity doping. To verify these hypotheses, we doped ZnO and CeO2, which have low and high bond enthalpies with oxygen, respectively, into the ITO thin film. Regardless of the bond enthalpy energy, the κl values of the two thin films increased due to excessive doping. Fourier transform infrared spectroscopy was conducted to determine the metal hydroxide formation. There was no significant difference in wave absorbance originating from the OH stretching vibration. Therefore, the increase in κl due to the excessive doping was due to the formation of localized regions in the thin film. These results could be valuable for various applications using other transparent conductive oxides and guide the control of the properties of thin films.

International audience; Thermoelectric thin films are of great interest to microelectronic devices and miniaturized temperature sensors. In this article, we have studied the influence of film thickness on the electrical and thermoelectric properties of Mg-doped CuCrO2 delafossite material (CuCrO2:Mg), a delafossite-type oxide. For this purpose, a serie of CuCr0.97Mg0.03O2 thin films with various thicknesses (25, 50, 100, 200, 300, 400 and 600 nm) have been deposited by Radio Frequency (RF) magnetron sputtering. The as-deposited films were annealed at 550 °C under vacuum to obtain well crystallized delafossite phase. Grazing incidence X-ray diffraction patterns indicated that samples had pure delafossite structure. The atomic force microscope observations revealed the increase of the grain size with increasing thickness. The electrical and thermoelectric properties are characterized in temperature ranging from 40 to 220 °C and they were thickness dependent. The thickness dependency of the Seebeck coefficient was not expected and indicated that the carrier density changes with thickness below 100 nm. The variation of the film resistivity below 100 nm thickness was explained by both the change of the carrier density and the potential barrier addition due to small grain size. Using the electrical conductivity, the polaron activation energy (Eσp = 0.131 eV for 100 nm thick sample) was determined and its variation indicated that the stress/strain effect in the film with increasing thickness impacts the mobility. Moreover, the unexpected increase of the resistivity between 400 and 600 nm was also explained by the micro-cracks formation. The electrical and thermoelectric measurements showed a degenerated hopping semi-conductor behavior for the whole thicknesses. The highest electrical conductivity (1.7 S·cm−1 at 40 °C) was obtained for 100 nm thick film which presented a Seebeck coefficient of +307 µV·K−1 at 40 °C. We report maximum power factor of 16 µW·m−1·K−2 at 40 °C for the optimum thickness of 100 nm, which reached 59 µW·m−1·K−2 at 200 °C. The above results were explained in terms of microstructure and stress/strain effect.

A nanoscale organic/inorganic hybrid thin film has been fabricated with the conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and SiC nanowires (SiC-NWs) defined as PEDOT:PSS/SiC-NWs by a facile dilution-filtration method and the thermoelectric (TE) performance has been investigated systematically. It has been demonstrated that a low content of SiC-NWs (

The principal motivation of this work is the development and realization of smart cooling and sensors devices based on the elaborated and characterized semiconducting thermoelectric thin film materials. For the first time, the details design of our sensor and the principal results are published. Fabrication and characterization of Bi/Sb/Te (BST) semiconducting thin films have been successfully investigated. The best values of Seebeck coefficient (α(T)) at room temperature for Bi2Te3, and (Bi1−xSbx)2Te3 with x = 0.77 are found to be −220 µV/K and +240 µV/K, respectively. Fabrication and evaluation of performance devices are reported. 2.60°C of cooling of only one Peltier module device for an optimal current of Iopt=2.50 mA is obtained. The values of temperature measured by infrared camera, by simulation, and those measured by the integrated and external thermocouple are reported. A sensitivity of the sensors of 5 mV Torr−1 mW−1 for the pressure sensor has been found with a response time of about 600 ms.

We investigated effects of the submicron structured thermoelectric thin films and module on their performance. The output power of the submicron structured module was 1.5 times greater than that of a smooth structured module.