Dye-sensitized solar cells have established themselves as a potential low-cost alternative to conventional solar cells owing to their remarkably high power-conversion efficiency combined with 'low-tech' fabrication processes. As a further advantage, the active layers consisting of nanoporous TiO2 are only some tens of micrometres thick and are therefore in principle suited for flexible applications. However, typical flexible plastic substrates cannot withstand the process temperatures of up to 500 degrees C commonly used for sintering the TiO2 nanoparticles together. Even though some promising routes for low-temperature sintering have been proposed, those layers cannot compete as regards electrical properties with layers obtained with the standard high-temperature process. Here we show that by a lift-off technique, presintered porous layers can be transferred to an arbitrary second substrate, and the original electrical properties of the transferred porous layers are maintained. The transfer process is greatly assisted by the application of composite layers comprising nanoparticles and nanorods.

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The power conversion efficiency of dye-sensitized solar cells crucially depends on the ability of the sensitizer to absorb light in a broad range of the solar spectrum. In order to increase this range of absorption, a tandem structure with two different sensitizer dyes in two different compartments of the cell, respectively, was realized. Overall power conversion efficiencies as high as η=10.5% and short circuit current densities of JSC=21.1 mA/cm2 were achieved under air mass 1.5 illumination with red dye and black dye in the upper and lower compartment of the cell, respectively.

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The adsorption of diethyl ether (Et 2 O) on Si(001) was studied by means of scanning tunneling microscopy (STM) and photoelectron spectroscopy. Et 2 O reacts on Si(001) via a datively bonded intermediate, which was isolated at surface temperatures below 100 K. At higher surface temperature, Et 2 O converts dissociatively into the final state by cleaving one O−C bond; the resulting −O−C 2 H 5 and −C 2 H 5 fragments are found to attach on two Si dimers of neighboring dimer rows. Tipinduced hopping of the −C 2 H 5 fragment on one dimer was observed at positive sample bias. The results are discussed in the context of recent experiments on the reaction of tetrahydrofuran (THF) on Si(001) (Mette et al. ChemPhysChem 2014, 15, 3725) and allow a more general description of the reaction of ethers on Si(001).