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We demonstrate hybrid solar cells with ZnO-nanorods (ZnO-NRs) prepared by a low temperature electrochemical method and small molecule organic absorber processed by dry organic vapor phase deposition. A homogeneous coverage of ZnO-NRs by the blend absorber consisting of zinc phthalocyanine (ZnPc) as donor and of fullerene C60 as acceptor is best realized when a thin C60 layer is first inserted at the ZnO-NR/ZnPc:C60 interface. ZnO-NR/C60/ZnPc:C60/MoO3/Ag solar cell devices with efficiencies of 2.8% under an illumination of 100 mW/cm2 at 25 °C are demonstrated.

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Single-phase Ga2Se3 films have been deposited with a growth rate of about 30 nm min−1 on clean and Mo-coated soda-lime glass substrates by chemical close-spaced vapour transport. The use of HCl/H2 as a transport agent results in a stoichiometric volatilization of the binary Ga2Se3 powder source material and the growth of Ga2Se3 films with reproducible composition. The films have been characterized using x-ray diffraction measurements, scanning electron microscopy observations, energy dispersive x-ray analysis, x-ray fluorescence spectrometry and elastic recoil detection analysis. A p-type conductivity was determined by means of the thermoelectric probe method. A Ga2Se3 band gap energy Eg = 2.56 eV has been found by optical measurements.

The chemical and electronic structure of MoO 3 thin films is monitored by synchrotron-based hard X-ray photoelectron spectroscopy while annealing from room temperature to 310 °C. Color-coded 2D intensity maps of the Mo 3d and O 1s and valence band maximum (VBM) spectra show the evolution of the annealing-induced changes. Broadening of the Mo 3d and O 1s spectra indicate the reduction of MoO 3 . At moderate temperatures (120–200 °C), we find spectral evidence for the formation of Mo 5+ and at higher temperatures (>165 °C) also of Mo 4+ states. These states can be related to the spectral intensity above the VBM attributed to O vacancy induced gap states caused by partial filling of initially unoccupied Mo 4d-derived states. A clear relation between annealing temperature and the induced changes in the chemical and electronic structure suggests this approach as a route for deliberate tuning of MoO 3 thin-film properties.

The system CuGaSe 2 -CuGa 3 Se 5 in thin films has been investigated. Layer synthesis was carried out by chemical close-spaced vapour transport (CCSVT) using Cu precursors on Mo/soda-lime glass substrates. The extension of deposition times in a two-step process led to final film compositions with [Ga]/[Cu] ratios ranging from 1 to 3, allowing the study of the phase transition mentioned above. Films showing chalcopyrite (1:1:2), OVC (1:3:5) and twophase were grown. X-ray emission spectroscopy and x-ray diffraction (XRD) techniques have been combined for a compositional and structural study of this material system probing both bulk and near surface properties of the films. This analysis was also extended to the rearsurface investigation of selected two-phase thin films and complemented with surface sensitive photoelectron spectroscopy (PES). From these results a growth model is presented for CuGa 3 Se 5 formation in gallium-rich, CCSVT-grown CuGa x Se y -films.

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