In most of the previous ultrafast electron injection studies of Ru(dcbpy)2(NCS)2-sensitized nanocrystalline TiO2 films, experimental conditions and sample preparation have been different from study to study and no studies of how the differences affect the observed dynamics have been reported. In the present paper, we have investigated the influence of such modifications. Pump photon density, environment of the sensitized film (solvent and air), and parameters of the film preparation (crystallinity and quality of the film) were varied in a systematic way and the obtained dynamics were compared to that of a well-defined reference sample: Ru(dcbpy)2(NCS)2-TiO2 in acetonitrile. In some cases, the induced changes in the dynamics were uncorrelated to the electron injection process. High pump photon density (not in the linear response region) and exposure of the sensitized film to air altered the picosecond-time-scale kinetics considerably, and the changes were attributed mostly to degradation of the dye. In other cases, changes in the measured kinetics were related to the electron injection processes: reducing the firing temperature of the nanocrystalline film or making the film via electron beam evaporation (EBE) resulted in a decrease of the overall crystallinity of the film, and the electron injection slowed. In the sensitized EBE films, in addition to an increased contribution of triplet excited-state electron injection, a new electron transfer (ET) process with a time constant of 200 fs was observed.

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The effect of the polymer−electrode interface on the photovoltaic performance of poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester based solar cells was investigated. Four forms of cathodes, Ca/Ag, Ca/Al, LiF/Al, and Al, were deposited on photoactive films. The Ca/Al cathode showed the best FF of 0.69, while Al produced the worst one of 0.55. The efficiency-limiting effect, a concavity in the fourth quadrant of the current−voltage characteristics, can be caused by a thermally degraded poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) anode or an oxidized Ca cathode. An inorganic material interlayer of CdSe between the photoactive layer and the cathode can, to some extent, inhibit the negative effect of polymer−metal interface.

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Organic light emitting diodes (OLED) are developing rapidly and provide a huge market potential for signage, lighting and display applications. Cost efficient manufacturing of OLED components on different flexible substrates is under heavy investigation. In this paper focus is on polymer OLEDs and their non‐vacuum solution processing using roll‐to‐roll (R2R) printing techniques. In this paper VTT's R2R manufacturing process capabilities for printed OLED components are presented. Several demonstrator concepts based on printed OLED technology are introduced including; printed OLED elements 1) in a smart package, 2) a 7‐segment display integrated in a ID‐1 card, 3) an electronics voting card with OLED indicator and 4) a 35 cm2 OLED lighting element printed on glass.

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