The recent results on the characterization of CulnSe(2) monogram layer solar cells are presented. The influence of different Cu/In ratio on solar cell characteristics was studied. It was determined that device-quality CulnSe(2) monograin powder could be grown from CuIn precursor alloys with a composition between 0.9 < Cu/In < 1. For absorber material, these powders were post-treated in sulphur vapour. The cells based on these absorbers showed efficiencies up to 9.5%. However, the quantum efficiency measurements revealed a significant loss in the long-wavelength range of photons lambda> 800 nm. The derivative of QE with respect to wavelength showed two peaks at the energy values of similar to 1.4 eV and similar to 1.03 eV, which proves that these sulphurised absorber materials consist of two different phases. (C) 2006 Elsevier B.V. All rights reserved.