Double doping induced power factor enhancement in CuCrO2 for high temperature thermoelectric application

In the present correspondence, polycrystalline sample of Mg and Ti doped CuCrO2 delafossite compounds are shown to exhibit enhanced power factor values in the absence of hole doping at the Cu site. All the compounds with a general composition of CuCr1-x(MgTi)(x)O-2 were synthesized by conventional solid state reaction method and X-ray powder diffraction (XRPD) analysis indicate a maximum solubility of x= 0.1. Scanning electron microscope (SEM) and Energy Dispersive Analysis of X Rays (EDAX) analysis reveal hexagonal shaped crystallites with the stoichiometric composition for all the compounds. X-ray Photoelectron Spectroscopy (XPS) data confirms the presence of all the ions in their usual valencies in the doped composition. Thermoelectric measurements indicate a metallic behaviour whereas the resistivity measurements indicate a semiconducting behaviour in case of the doped compositions giving a highest power factor of 8.0 x 10(-5) Wm(-1) K-1 for the maximum dopant concentration of x = 0.1 at 950 K. (C) 2018 Elsevier B.V. All rights reserved.