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Large Stokes shift downshifting organolanthanide complex, Eu(tta)(3)phen, is examined for inclusion in polymeric layers to replace the UV blocking layer in dye sensitized solar cell (DSSC) technology. The UV blocking layer increases stability but power conversion efficiency decreases as incident UV photons are not converted into photocurrent. Eu(tta) 3phen doped polymeric film are prepared and attached to DSSC devices following optimized thickness and concentration from a ray-trace numerical model for the specific DSSC. External quantum efficiency is significantly increased in the UV spectral region compared to DSSCs utilizing a passive, non-luminescent, UV-BL. High Eu(tta)(3)phen film transparency in the visible range minimizes DSSC EQE losses at visible wavelengths. Short-circuit current (I-sc) enhancement due to downshifting is demonstrated (similar to 1%) in small-scale DSSC prototypes, where the specific geometry limits the photon collection efficiency and overall enhancement. Model predictions indicate that 2%-3% I-sc enhancement is realizable in flexible single DSSC compared to, non-luminescent, UV-BL. Added to this, in outdoor conditions taking into account diffuse light, the increment in Isc can increase 50% more. Although photostability of the blended LSS-DS polymer films is not sufficient to be useful for medium-long term outdoor PV applications, the results demonstrate that significant efficiency enhancement can be realized. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

N -type organic thin-film transistors based on N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide have been fabricated by thermal evaporation at different substrate temperatures. The best device was obtained at 120 °C with a field-effect mobility of 0.12 cm 2 /V·s and threshold voltage around 46 V. In this work, the microstructure of the films is correlated with the device performance. In particular, the dependence of the activation energy for the channel conductance on gate voltages has been related to the properties of the layers.

Structural and optical characterization of copper phthalocyanine thin film thermally deposited at different substrate temperatures was the aim of this work. The morphology of the films shows strong dependence on temperature, as can be observed by atomic force microscopy and x-ray diffraction spectroscopy, specifically in the grain size and features of the grains. The increase in the crystal phase with substrate temperature is shown by x-ray diffractometry. Optical absorption coefficient measured by photothermal deflection spectroscopy and optical transmittance reveal a weak dependence on the substrate temperature. Besides, the electro-optical response measured by the external quantum efficiency of Schottky ITO/CuPc/Al diodes shows an optimized response for samples deposited at a substrate temperature of 60¿°C, in correspondence to the I–V diode characteristics.