2:00 PM - 2:15 PM
▲ [14p-2A-1] [JSAP Young Scientist Award Speech] Thermoelectric power enhancement of PEDOT:PSS in high-humidity conditions
Keywords:Conducting polymer,Thermoelectric
Organic thermoelectric materials attracted much attention recently, and remarkable thermoelectric performance were reported by using poly(3,4-ethylenedioxythiophene) (PEDOT) based materials.[1] The possibility to power practical devices using screen-printed organic thermoelectric modules was also demonstrated.[2] At the same time, there are other concerns in the PEDOT based systems such as doping mechanisms of PEDOT and the anisotropicity due to film morphology.[3] In the first part of this presentation, we will discuss the apparent Seebeck coefficient enhancement of PEDOT films in humidity more than 90%.[4] This enhancement could be partly related to proton doping in PEDOT films. It is known there are two different doping mechanisms in p-type conducting polymers. The first one is oxidative doping which is based on the charge transfer from the host to dopant. The second mechanism is protonic acid doping. This is well studied in polyaniline and polypyrrole. PEDOT are synthesized using Fe3+ or peroxodisulfate as an oxidant, and therefore, as a general consideration, PEDOT is oxidatively doped by oxidizing agents. It is important to note that the molecular weight of PEDOT is not high, and the a-position of the end-thiophene could be protonated. The polar solvents such as H2O could interact with the proton which effects the charge delocalization. In the second part of this presentation, we will report the anisotropic carrier transport properties and thermal diffusivity in PEDOT/PSS films. A novel and facile approach for in-plane thermal conductivity measurement will be presented. Our results suggested the calculated figure-of-merit by using in-plane electrical conductivity, in-plane Seebeck coefficient and through-plane thermal conductivity could give an overestimated value.[5]
Reference
[1] Q.S. Wei et al., Materials, 2015, 8, 732. [2] Q.S. Wei et al., RSC Adv., 2014, 4, 28802. [3] Q.S. Wei et al., Adv. Mater., 2013, 25, 2831. [4] Q.S. Wei et al., Appl. Phys. Express, 2014, 7, 031601. [5] Q.S. Wei et al.,ACS Macro Lett., 2014, 3, 948.
Acknowledgment. This work was supported by TherMAT from NEDO and a Grant-in-Aid for Research Activity Start-up 25888025 from MEXT.
Reference
[1] Q.S. Wei et al., Materials, 2015, 8, 732. [2] Q.S. Wei et al., RSC Adv., 2014, 4, 28802. [3] Q.S. Wei et al., Adv. Mater., 2013, 25, 2831. [4] Q.S. Wei et al., Appl. Phys. Express, 2014, 7, 031601. [5] Q.S. Wei et al.,ACS Macro Lett., 2014, 3, 948.
Acknowledgment. This work was supported by TherMAT from NEDO and a Grant-in-Aid for Research Activity Start-up 25888025 from MEXT.