In this study, nanoparticle-based approach was suggested for the formation of CuInSe(2) (CIS) layer. Nanoparticles with core-shell structure were used as the precursor material, and binary phases were used as core and shell material,in the core-shell structure to maximize the kinetics of CIS formation reaction. From the investigation of the effect of heating rate on Se-loss, it was concluded that Se-loss could be minimized by using high heating rate and core-shell structure with a binary compound. By minimizing Se-loss before and during CIS formation reaction, it was shown that CIS layer could be formed without Se overpressure. CIS solar cell made in this study showed the highest efficiency of 1.11%, which showed a CIS layer for the device could be obtained without selenization process. (C) 2008 Elsevier B.V. All rights reserved.