Preparation of p-type CuCr1-xMgxO2 bulk with improved thermoelectric properties by sol-gel method

Fine powders of p-type CuCr1-x Mg (x) O-2 (0 a parts per thousand currency sign x a parts per thousand currency sign 0.15) with improved thermoelectric properties were synthesized by sol-gel method through nitrate-citrate route. The sintered CuCr1-x Mg (x) O-2 (0 a parts per thousand currency sign x a parts per thousand currency sign 0.15) bulk contained the CuCr1-x Mg (x) O-2 phase with a rhombohedral structure, R3 m, along with trace second phase CuO, MgCr2O4. With the doping amount of Mg increasing, the grain size enlarged with oppositely decreased of the porosity. The substitution of Mg could give four orders improvement on electrical conductivity up to 10.34 S/cm at room temperature compared with the undoped samples. The positive Seebeck coefficients of doping oxides implied the typical p-type conducting oxides obtained by sol-gel method. The highest value of power factor has been achieved to be 1.37 x 10(-4) Wm(-1) K-2 for CuCr0.90Mg0.10O2 at 470 K. As a conclusion, we realized that the sol-gel method is a very effective and feasible shortcut on transparent oxide synthesis with desirable thermoelectric properties.