CuIn(5)Ss(8) homogeneous crystals of n-type conductivity have been grown. Donor centers activation energy has been estimated. In/n-Culn(5)Se(8) Schottky barriers have been created and the first spectral dependencies of quantum efficiency of photoconversion of these structures have been derived. The nature of interband optical transitions has been interpreted and the band gap values for direct and indirect transitions in Culn(5)Se(8) crystals have been determined on the results of analysis of the Schottky barriers photoactive edge absorption. A possibility of utilization of Culn(5)Se(8) crystals in wide-band photoconverters of the optical radiation has been established. (C) 2007 Elsevier B.V. All rights reserved.