Thermoelectric properties of Sn<inf>z</inf>Co<inf>4</inf>Sb <inf>12-y</inf>Te<inf>y</inf> skutterudites

Sn-filled and Te-doped CoSb3 skutterudites (SnzCo 4Sb12yTey) were synthesized by encapsulated induction melting, and their thermoelectric properties were investigated from 300 K to 700 K. Single δ-phase was successfully obtained by the subsequent heat treatment at 823 K for 6 days. Intrinsic CoSb 3 showed n-type conductivity from 300 K to 400 K and there is a transition to p-type conductivity above 400 K. Sn-filled SnzCo 4Sb12 showed p-type conductivity and Sn-fllled/Te-doped SnzCo4Sb12-yTey showed n-type conductivity from 300 K to 700 K, indicating that Te atoms substituting for Sb atoms acted as electron donors. Thermal conductivity was considerably reduced by filling and doping due to the phonon scattering. Sn filling effect and Te doping effect are examined and compared in this study. © 2006 IEEE.