The paper summarizes the results of R/D in new alternative materials and in thin film and monograin solar cells at EU Centre of Excellence in PV Materials and Devices at TUT. The defect structure of various chalcopyrite compounds (CuInSe(2), CuInS(2), CuGaSe(2), CuGaTe(2), AgGaTe(2), CuInTe(2), AgInTe(2), Cu(2)ZnSnSe(4)) was studied. A novel route of spray deposition was developed to prepare ZnO layers comprising nanorods as a promising material for solar cells. Technological conditions for controlled ZnS chemical bath deposition were determined. The influence of parameters of electrodeposition and annealings in different atmosphere to the composition and morphology of CuInSe(2) thin films was studied. Hybrid solar cells on the basis of CuInS(2) and CdTe photoabsorbers in combination with organic functional layers were prepared and investigated. All the obtained results were used to optimize the technology of producing solar cell structures in different designs. (c) 2007 Elsevier B.V. All rights reserved.