Preparation and thermoelectric properties of Ga-substituted p-type fully filled skutterudites CeFe4−xGaxSb12

► Ga as an effective substitute for Fe in p-type skutterudites CeFe4−xGaxSb12. ► The solubility limit of Ga at Fe sites is −0.11 in CeFe4−xGaxSb12. ► Ga barely affects the electronic structure near the Fermi level.