Strontium-doped samarium cobaltite (Sm0.5Sr0.5CoO3, SSC) has attracted increasing attention as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to its mixed-conduction characteristics and relatively high ionic conductivity. In this paper, sol-gel-derived SSC films were deposited on yttria stabilized zirconia (YSZ) substrates from an alkoxide solution of strontium isopropoxide, samarium isopropoxide and cobalt isopropoxide. The alkoxide solution was chelated with 2-ethylacetoacetate (CH3COCH2COOC2H5), and the effect of polyethylene glycol (PEG) addition on the crystallization behavior and microstructure evolution of SSC films was investigated. XRD, TGA and SEM measurements indicated that single-perovskite phase SSC films were formed when the films were heated at 700 degrees C, and PEG could significantly refine the crystalline size of the SSC film from around 100-50 nm. (c) 2005 Elsevier B.V. All rights reserved.