Facile synthesis and thermoelectric properties of aluminum doped zinc oxide/polyaniline (AZO/PANI) hybrid

Now-a-days metal oxide-conducting polymer composites are used as promising candidates for light-weight, lowcost and non-toxic thermoelectric applications. In the present work, aluminum (Al) doped zinc oxide/ polyaniline-AZO/PANI (AZP) hybrid are successfully synthesized by combining sol-gel and in-situ oxidative polymerization method. The materials are structurally characterized by X-ray diffraction pattern (XRD), transmission electron microscopic (TEM) and field emission scanning electron microscopic (FESEM) images. Measurement of thermoelectric properties of AZO/PANI hybrids reveal a simultaneous improvement in electrical conductivity which is attributed to carrier mobility and Seebeck coefficient due to scattering of low-energy carriers via energy-filtering effect. Carrier concentrations have been evaluated from Hall-Effect measurements. The mechanism of charge carrier transport follows a two dimensional variable-range hopping. Inclusion of AZO on the layers of PANI reduces the thermal conductivity to a great extend compared to pure AZO, leading to enhance the room temperature dimensionless figure of merit (ZT = 0.0035). The probable interaction of formation of the hybrid of AZO and PANI validates the enhancement of material property.