Flexible\nand Transparent Organic–Inorganic\nHybrid Thermoelectric Modules

Abstract

Light-weight,\nmechanically flexible, transparent thermoelectric\nmodules are promising as portable and easy-to-integrate energy sources.\nHere, we demonstrate flexible, transparent thermoelectric modules\nby using a conducting polymer poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate)\n(PEDOT:PSS) as the p-type leg and indium tin oxide (ITO)-PEDOT:PSS\nas the n-type leg. Main observations include the following: (1) the\nbilayer combination of ITO-PEDOT:PSS (PEDOT:PSS coated on top of the\nITO) displays a negative Seebeck coefficient (<i>S</i>)\nand the value is similar to that of the ITO single layer; (2) the <i>S</i> value of the ITO-PEDOT:PSS is almost not dependent on\nthe area ratio of the stacked PEDOT:PSS and ITO; and (3) the conducting\npolymer PEDOT:PSS deposition on top of ITO helps the ITO not to generate\ncracks during bending, which enhances the mechanical flexibility of\nthe ITO. On the basis of these observations, thermoelectric modules\nwith eight pairs of junctions are fabricated and the thermoelectric\nmodules’ Δ<i>V</i>/Δ<i>T</i> (modules’ generated thermovoltage per temperature difference)\nis nearly the addition of <i>S</i> values of all legs. Thermoelectric\nmodules show good mechanical flexibility and air stability. Applications\nof thermoelectric modules have also been demonstrated to produce thermovoltage\nvia the temperature difference produced by a human hand or warm water.