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In this study, a range of miniaturized Ag/AgCl reference electrodes with various layouts were successfully fabricated on wafer-level silicon-based substrates with metallic intermediate layers by precisely controlling the electrochemical deposition of Ag, followed by electrochemical chlorination of the deposited Ag layer. The structure, as well as the chemical composition of the electrode, were characterized with SEM & EDS. The results showed that the chlorination is very sensitive to the applied electric field and background solution. Potentiostatic chlorination, in combination with an adjusted mushroom-shaped Ag sealing deposition, enabled the formation of electrochemical usable Ag/AgCl layers. The stability of the electrodes was tested using open circuit potential (OCP) measurement. The results showed that the reference electrodes stayed stable for 300 s under 3 M KCl solution. The first stage study showed that the stability of the Ag/AgCl reference electrode in a chip highly depends on chip size design, chlorination conditions, and a further protection layer.

An approach for direct electron beam micropatterning is presented, whereby the emission of an organic light-emitting diode (OLED) can be modified at high-resolution by using a focused electron beam through its encapsulation. By subsequent thermal annealing it is possible to tune the optical and electrical properties of the OLED.

We report on organic $p\text{\ensuremath{-}}i\text{\ensuremath{-}}n$ homojunctions composed of differently doped vacuum-deposited pentacene layers. We observe a remarkably high built-in voltage of 1.65 V. An analysis of the current-voltage characteristics under dark and illuminated conditions reveals that the open-circuit voltage is directly related to the built-in voltage and that the recombination process is influenced by the distinct charge transport properties of electrons and holes in the pentacene film. By a comparison with $p\text{\ensuremath{-}}i\text{\ensuremath{-}}p$ and $n\text{\ensuremath{-}}i\text{\ensuremath{-}}n$ single-carrier homojunctions, deep trap states located around 0.63 eV below the electron transport level are shown to influence the properties.

Organic conducting polymers are promising electrode materials for printable organic electronics. One of the most studied conducting polymers is PEDOT:PSS, which is sufficiently conductive and transparent, but which shows some drawbacks, such as hygroscopicity and acidity. A new approach to stabilize PEDOT in aqueous dispersions involves the replacement of PSS with a basic polyanion based on a polystyrene backbone with (trifluoromethylsulfonyl)imide (TSFI) side groups. The PEDOT:PSTFSIK dispersions were obtained by oxidative polymerization of EDOT in an aqueous PSTFSIK solution and were characterized with regard to their composition, morphology, doping, rheological behavior, and optoelectronic performance. The PEDOT:PSTFSIK dispersions showed excellent printability and good optoelectronic performance (238 Ohm sq−1 at 91 % transmittance, s>260 S cm−1) and were successfully integrated as flexible electrodes in OLED and OPV devices.

Bulk heterojunction organic solar cells with a vertical variation of the C60:ZnPc composition within the absorption layer have been fabricated. The resulting gradient layer has been characterized by UV/vis transmission and reflection spectroscopy. Depending on the mixing strategy, the formation of higher aggregated ZnPc species can be initialized earlier in a blended thin film. The gradient strength has been varied and its influence on the solar cell performance has been determined. A variation of the absorption layer thickness has been carried out to investigate a possible charge carrier transportation improvement. In order to explain the positive effect of a graded structure within the absorption layer, detailed voltage-dependent spectral response measurements have been performed. It is shown that not only the absorption behavior of the cell is improved, but also the charge carrier transportation properties.

To leverage the potential of organic solar cells, suitable materials for the photoactive layers have to be found. Herein, we show that the well-known fluorescent dye 3-(2′-benzothiazolyl)-7-diethylaminocoumarin works as an efficient light absorber material with a sensitivity at wavelengths from 400 to 650 nm. In combination with doped transport layers and optimization of the photodiode stack, a power conversion efficiency up to 1.9% under air mass 1.5 and 100 mW/cm 2 illumination could be achieved.

We present a QQVGA top emitting monochrome AMOLED display with 85dpi resolution using an organic TFT backplane on low temperature PEN-foil. The backplane process flow is based on a 7 layer photolithography process that yields a final mobility of the OTFT of ∼0.4 cm2/Vs. The aperture ratio of the top-emitting OLEDs is over 75%. For operation at 10 V supply voltage (VDD), the brightness of the display using red and green OLEDs exceeds 200 cd/m2.

We present our recent achievements in organic semiconductor technology in two emerging application areas. We show that the performance of our technology approaches the requirements for Electronic Product Coding RFID tags. Also, backplanes of OLED displays are enabled by the unique compatibility of pentacene transistors with high-k gate dielectrics. © 2009 IEEE.