The adsorption of Ru dye N3 [RuII(2,2‘-bipyridyl-4,4‘-dicarboxylate)2(NCS)2] from ethanol solution and gas-phase adsorption and coadsorption of the solvent acetonitrile on liquid nitrogen cooled nanocrystalline (nc) TiO2 films have been investigated using highly surface sensitive synchrotron-induced photoelectron spectroscopy. Resonantly excited Ti3+-related band gap states form a peak 2.2 eV above the leading edge of the valence band, and additional states up to the Fermi level are found. The intensities of the gap states and related Ti3+ 2p emissions of pristine samples depend strongly on sample preparation and history. Gap-state-related emissions are partially quenched by dye as well as acetonitrile adsorption. Quenching of gap states due to acetonitrile is reversible. The maximum of the highest occupied molecular orbital (HOMO) emission of the dye is found 1.6 eV above the leading edge of the nc-TiO2 valence band. The binding energies of dye orbitals are increased upon acetonitrile coadsorption. The HOMO emission is shifted by 150 meV and that of N 1s of the dye NCS group by approximately 200 meV. These shifts are reversed upon acetonitrile desorption.

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At the synchrotron BESSY we run the experimental station SoLiAS, dedicated to solid–liquid interface analysis with soft X-ray induced photoelectron spectroscopy (SXPS). SoLiAS allows wet chemically prepared surfaces to be transferred to the ultra high vacuum without contact with ambient air. In addition in situ (co)adsorption of volatile solvent species onto liquid nitrogen cooled samples is possible. SoLiAS proves to be very useful in analyzing the chemical and electronic structure at the solid–liquid interface of dye–sensitized solar cells. The standard dye RuII(2,2?-bipyridil-4,4?-dicarboxylate)2(NCS)2 was adsorbed from ethanol solution under clean N2 atmosphere in an UHV-integrated electrochemical cell (EC). The standard solvent acetonitrile was adsorbed in situ from the gas phase. For comparison also the nonpolar solvent benzene was adsorbed. Ex situ sintered nanocrystalline anatase substrates as well as in situ deposited polycrystalline TiO2 samples were used, which show a similar distribution of two types of occupied surface states. Distinct reversible changes occur in synchrotron-induced photoelectron valence band and core level spectra when the solvent acetonitrile is adsorbed to pristine and dye-covered TiO2 substrates. TiO2 surface states are quenched and the line width of the dye S2p emission decreases strongly. Based on the experimental results the alignment of the photovoltaic relevant electronic states and a model on the dye–solvent interaction can be deduced that points to the promotion of vectorial charge transfer by increased dye orientation due to solvation.

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A stabilized total‐area efficiency above 10% (ISC = 1.46 A, VOC = 148 V, FF = 67%, Pmpp = 145W, total area of 1.43m2) has been achieved on Gen 5 modules for the first time with an amorphous/microcrystalline silicon solar cell. The efficiency was enhanced by improving the light management and reducing the light induced degradation. The short circuit current density Jsc was enhanced by the introduction of internal light trapping using textured ZnO as the front transparent conductor, the implementation of an innovative µc‐SiOx based p‐layer and by an optical filter between the top and bottom cells of the tandem junction. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)