Effect of boron-doping on thermoelectric properties of rutile-type titanium dioxide sintered materials

The electrical and thermal transport properties of boron-doped rutile-type TiO2 were investigated. The rutile-type TiO2 powder was mixed with B2O3, TiB2 or B and the mixtures were sintered using the pulse current sintering method at 1473 K. Secondary ion mass spectroscopy (SIMS) and X-ray diffraction (XRD) measurements showed that B or TiB2 addition was effective for boron-doping. The boron was well distributed in the sintered materials and the unit cell volume of rutile increased as the amounts of added B or TiB2 increased. The electrical resistivity and Seebeck coefficient at 300 K decreased with an increase in the unit cell volume indicating that boron addition leads to an increase in the electron concentration. Thermal conductivity at room temperature also decreased with an increase in unit cell volume and as a result the thermoelectric figure of merit for rutile-type TiO2 was enhanced by boron-doping.

Research highlights▶ Boron-doped rutile-type TiO2 was prepared by pulsed current sintering method. ▶ The B and TiB2 addition was effective for boron-doping of RTO. ▶ Both electrical resistivity and thermal conductivity decreased using B or TiB2 as a additive. The thermoelectric figure of merit was enhanced by boron-doping.