Ge 2 Sb 2 Te 5 nanowire arrays와 PEDOT: PSS를 이용한 유·무기 열전 복합소재 합성 및 특성평가

Hybrid organic/inorganic composites have recently been investigated in the thermoelectric field in an effort to interdependently manipulate the charge carriers, which are interconnected with electrical and thermal transport. The decoupling of a charge carrier`s roles in the hybrid structures can result in enhanced thermoelectric performance, by only exploiting the high seebeck coefficient of the inorganic part and the high electrical conductivity of the organic part. In this work, we demonstrated the enhanced thermoelectric performance of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by employing the nanoimprinted Ge2Sb2Te5 nanowire arrays to form a vast network of PEDOT:PSS/ Ge2Sb2Te5 nanowire composites. These structures showed an approximately ten times higher Seebeck coefficient than the PEDOT:PSS itself without damaging electrical conductivity. In addition, ethylene glycol (EG) was used to selectively de-dope PSS, to enhance the electrical conductivity of the composites. Different EG concentrations were needed to optimize the de-doping effect, and the best thermoelectric power factor (P.F.) of ~1.6 × 103 μW/mK2 was achieved with an EG level of 6 vol% in our configuration. This result is 5 times and 22 times higher than that of GST thin film (320 μW/mK2) and PEDOT:PSS/Te nanorods composites (70.9 μW/mK2). Electrical and thermoelectric measurements were conducted in both parallel and perpendicular directions to observe the dependence of the transport property on the charge carrier pathway under the influence of the interface, to achieve a higher thermoelectric P.F.. The parallel direction was 1.6 times higher than the perpendicular direction. (Received October 4, 2016; Accepted December 1, 2016)