Culebras Mario, Uriol Belén, Gómez Clara M, Cantarero Andrés
Materials Science Institute, University of Valencia, PO Box 22085, 46071 Valencia, Spain.
Phys Chem Chem Phys. 2015 Jun 21;17(23):15140-5. doi: 10.1039/c5cp01940k.
Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films have been prepared by an electrochemical method in a three electrode cell. The films have been obtained at different oxidation levels regarded as bipolaron, polaron and neutral states by varying the voltage, as is usually done in conjugated heterocyclic polymers. The voltage (-0.2 < V < 1.0 V) has been applied versus a Ag/AgCl reference electrode, producing a variation of one order of magnitude in the electrical conductivity and the Seebeck coefficient of the films. In the voltage range explored, the electrical conductivity increases from 80 to 766 S cm(-1) in PEDOT and from 15 to 160 S cm(-1) in PPy, while the Seebeck coefficient decreases from 37.0 to 9.6 μV K(-1) for PEDOT and from 51.0 to 6.7 μV K(-1) for PPy. The thermal conductivity remains unchanged with the oxidation state of the film, κ ≈ 0.35 ± 0.02 W m(-1) K(-1) for PEDOT and 0.17 ± 0.02 W m(-1) K(-1) for PPy. A maximum thermoelectric efficiency of 1.4 × 10(-2) for PEDOT and 6.8 × 10(-3) for PPy has been achieved. These changes are related to the doping level of the polymer films and they can be accurately controlled by the applied voltage. In this work, we provide a very simple method to control and optimize the power factor or the figure of merit of conducting polymers.
聚（3,4 - 亚乙基二氧噻吩）（PEDOT）和聚吡咯（PPy）薄膜通过电化学方法在三电极池中制备。如在共轭杂环聚合物中通常所做的那样，通过改变电压，在被视为双极化子、极化子和中性态的不同氧化水平下获得了这些薄膜。相对于Ag/AgCl参比电极施加电压（-0.2 < V < 1.0 V），使薄膜的电导率和塞贝克系数产生了一个数量级的变化。在所探索的电压范围内，PEDOT的电导率从80 S cm⁻¹增加到766 S cm⁻¹，PPy的电导率从15 S cm⁻¹增加到160 S cm⁻¹，而PEDOT的塞贝克系数从37.0 μV K⁻¹降低到9.6 μV K⁻¹，PPy的塞贝克系数从51.0 μV K⁻¹降低到6.7 μV K⁻¹。热导率随薄膜的氧化态保持不变，PEDOT的κ≈0.35±0.02 W m⁻¹ K⁻¹，PPy的κ≈0.17±0.02 W m⁻¹ K⁻¹。PEDOT的最大热电效率达到1.4×10⁻²，PPy的最大热电效率达到6.8×10⁻³。这些变化与聚合物薄膜的掺杂水平有关，并且可以通过施加的电压精确控制。在这项工作中，我们提供了一种非常简单的方法来控制和优化导电聚合物的功率因数或品质因数。
