Anomalous effect of vanadium boride seeding on thermoelectric properties of YB22C2N

Highlights: ► We doped YB22C2N; the long awaited n-type counterpart to p-type boron carbide. ► VB2 seeding of YB22C2N showed striking results. ► Thermal treatment effects led to VB2 being intrinsically doped. ► Large increase of both Seebeck coefficient and electrical conductivity was obtained. - Abstract: Vanadium boride seeded YB22C2N were synthesized and the thermoelectric properties investigated. YB22C2N is representative of the series of rare earth borocarbonitrides which is the potential long awaited n-type counterpart to p-type boron carbide. VB2 seeded samples of YB22C2N were prepared using VB2 directly as an initial additive and V2O3 which also results in formation of vanadium diboride in the final product. The resistivity and Seebeck coefficient of samples were measured in the temperature range of 323 K to 1073 K. A dramatic effect of thermal treatment on the Seebeck coefficient of VB2 seeded samples was observed, and it is indicated that there is possible partial intrinsic doping of vanadium into YB22C2N. VB2 is revealed to be a promising additive to improve the thermoelectric properties of YB22C2N. An enhancement of more than 220% of the maximum absolute value of the Seebeck coefficient was obtained while the resistivity was also reduced considerably