摘要
The overall purpose of the present study is basically to understand the manifestation of the thermo-electrical properties of the matrix ZnO-P<sub>2</sub>O<sub>5</sub> first, and of the ZnO-P<sub>2</sub>O<sub>5</sub> composites loaded with different volume fractions of nickel (Ni) as conductive fillers. In the matrix ZnO-P<sub>2</sub>O<sub>5</sub>, the values of electrical conductivity varied between 1.14 × 10<sup>-8</sup> and 7.8 × 10<sup>-7</sup> (S/cm), and the Seebeck coefficient value varied between minimal value 265 and maximal value 670 (μV/K) in the studied temperature. In composite ZnO-P<sub>2</sub>O<sub>5</sub>/Ni, it was shown that the Seebeck coefficient changed from high positive to negative values when the filler amount was increased, indicating a non-conducting to conducting phase transition. Such behavior exhibits that this transition is accompanied by the passing of carrier charge from p to n type. The study of thermoelectrically transport for high volume fraction of filler enabled the achievement, for the first time on this kind of composites, of an original transition called PTC transition. Thus, highest values of power factor (PF = S<sup>2</sup> ≈ 2 × 10<sup>-3</sup> W·m<sup>-1</sup><sub>·</sub>K<sup>-2</sup> at 407 K) were obtained, giving a possibility of industrial applications.
The overall purpose of the present study is basically to understand the manifestation of the thermo-electrical properties of the matrix ZnO-P<sub>2</sub>O<sub>5</sub> first, and of the ZnO-P<sub>2</sub>O<sub>5</sub> composites loaded with different volume fractions of nickel (Ni) as conductive fillers. In the matrix ZnO-P<sub>2</sub>O<sub>5</sub>, the values of electrical conductivity varied between 1.14 × 10<sup>-8</sup> and 7.8 × 10<sup>-7</sup> (S/cm), and the Seebeck coefficient value varied between minimal value 265 and maximal value 670 (μV/K) in the studied temperature. In composite ZnO-P<sub>2</sub>O<sub>5</sub>/Ni, it was shown that the Seebeck coefficient changed from high positive to negative values when the filler amount was increased, indicating a non-conducting to conducting phase transition. Such behavior exhibits that this transition is accompanied by the passing of carrier charge from p to n type. The study of thermoelectrically transport for high volume fraction of filler enabled the achievement, for the first time on this kind of composites, of an original transition called PTC transition. Thus, highest values of power factor (PF = S<sup>2</sup> ≈ 2 × 10<sup>-3</sup> W·m<sup>-1</sup><sub>·</sub>K<sup>-2</sup> at 407 K) were obtained, giving a possibility of industrial applications.
作者
Omar Oabi
Abdelkarim Maaroufi
Bruno Lucas
Aumeur El Amrani
Omar Oabi;Abdelkarim Maaroufi;Bruno Lucas;Aumeur El Amrani(Laboratory of Composite Materials, Polymers and Environment, Department of Chemistry, Faculty of Sciences, University Mohammed V, Rabat-Agdal, Morocco;XLIM UMR 6172-Université de Limoges/CNRS, Limoges Cedex, France;LPSMS, FST Errachidia, University Moulay Ismail Meknès, Errachidia, Morocco)