Effect of grain size on thermoelectric properties of (Ca2.6Bi0.4)Co4O9 thin film

Abstract

Ca_2.6Bi_0.4Co₄O₉ thin films with different grain sizes (50 - 500 nm) were prepared by a spin coating method. Films were polycrystalline in nature and oriented preferentially in the (001) direction. Electrical properties were measured to study the effect of grain size on thermoelectric (TE) properties. The film with grain size of about 100 nm has the largest TE power factor. An improvement of TE performance can be obtained by optimizing the grain size.