Browsing by Author "Boopathi, Karunakara M."

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Enhanced Thermoelectric Performance of PEDOT:PSS Flexible Bulky Papers by Treatment with Secondary Dopants
(2015-01-14)
Mengistie, Desalegn A.
;
Chen, Chang-Hsiao
;
Boopathi, Karunakara M.
;
Pranoto, Ferry W.
;
Li, Lain-Jong
For inorganic thermoelectric materials, Seebeck coefficient and electrical conductivity are interdependent, and hence optimization of thermoelectric performance is challenging. In this work we show that thermoelectric performance of PEDOT:PSS can be enhanced by greatly improving its electrical conductivity in contrast to inorganic thermoelectric materials. Free-standing flexible and smooth PEDOT:PSS bulky papers were prepared using vacuum-assisted filtration. The electrical conductivity was enhanced to 640, 800, 1300, and 1900 S cm(-1) by treating PEDOT:PSS with ethylene glycol, polyethylene glycol, methanol, and formic acid, respectively. The Seebeck coefficient did not show significant variation with the tremendous conductivity enhancement being 21.4 and 20.6 mu V K-1 for ethylene glycol- and formic acid-treated papers, respectively. This is because secondary dopants, which increase electrical conductivity, do not change oxidation level of PEDOT. A maximum power factor of 80.6 mu W m(-1) K-2 was shown for formic acid-treated samples, while it was only 29.3 mu W m(-1) K-2 for ethylene glycol treatment. Coupled with intrinsically low thermal conductivity of PEDOT:PSS, ZT approximate to 0.32 was measured at room temperature using Harman method. We investigated the reasons behind the greatly enhanced thermoelectric performance.