A synergetic approach of band gap engineering and reduced lattice thermal conductivity for the enhanced thermoelectric property in Dy ion doped ZnO

Donor cation substituted ZnO demonstrate a promising performance for the green energy harvesting and conservation. In this work we report the marked improvement in the thermoelectric transport properties of rare earth Dy ion substituted ZnO to achieve a maximum figure of merit ZT as 0.11 at 923 K for the 0.1 atomic% of Dysprosium doping. The enhancement in the TE properties were mainly through the increase in carrier concentration and by the energy filtering of carriers at the potential barrier formed in the lattice by Dy doping, which has a large atomic size and localized magnetic moment due to the presence of unpaired electrons. With the substitution of Dy3+ ion, excess electrons were generated in the conduction band of ZnO lattice and they were free to move hence to contribute for the upliftment of Fermi level towards the conduction band with an increment in the effective electron mass. Introduction of donor ion causes distortion of lattice structure and the induced strain responsible for the reduction of lattice thermal conductivity. (C) 2019 Elsevier B.V. All rights reserved.