We present highly transparent and conductive silver thin films in a thermally evaporated dielectric/metal/dielectric (DMD) multilayer architecture as top electrode for efficient small molecule organic solar cells. DMD electrodes are frequently used for optoelectronic devices and exhibit excellent optical and electrical properties. Here, we show that ultrathin seed layers such as calcium, aluminum, and gold of only 1 nm thickness strongly influence the morphology of the subsequently deposited silver layer used as electrode. The wetting of silver on the substrate is significantly improved with increasing surface energy of the seed material resulting in enhanced optical and electrical properties. Typically thermally evaporated silver on a dielectric material forms rough and granular layers which are not closed and not conductive below thicknesses of 10 nm. With gold acting as seed layer, the silver electrode forms a continuous, smooth, conductive layer down to a silver thickness of 3 nm. At 7 nm silver thickness such an electrode exhibits a sheet resistance of 19 Ω/□ and a peak transmittance of 83% at 580 nm wavelength, both superior compared to silver electrodes without seed layer and even to indium tin oxide (ITO). Top‐illuminated solar cells using gold/silver double layer electrodes achieve power conversion efficiencies of 4.7%, which is equal to 4.6% observed in bottom‐illuminated reference devices employing conventional ITO. The top electrodes investigated here exhibit promising properties for semitransparent solar cells or devices fabricated on opaque substrates.

Oxide/silver/oxide multilayers as semitransparent top electrode for small molecule organic solar cells (OSCs) are presented. It is shown that two oxide layers sandwiching a central metal layer greatly improve the stability and lifetime of the organic solar cell. Thermally evaporated MoO3, WO3, or V2O5 layers are employed as an interlayer for subsequent silver deposition and significantly change the morphology of the ultrathin silver layer, improving charge extraction and electrodes series resistance. The transmittance of the electrode is increased by introducing oxide or oxide and organic multilayers as capping layer, which leads to higher photocurrent generation in the absorber layer. Application of 1 nm MoO3/11 nm Ag/10 nm MoO3/50 nm Alq3 multilayer electrodes in OSCs lead to an efficiency of 2.6% for a standard ZnPc:C60 cell, showing superior performance compared to devices with pure silver top contacts. The device lifetime is also strongly increased. MoO3 layers can saturate and stabilize the inner and outer metal surface, passivating it against most of the degradation mechanisms. With such an oxide/silver/oxide multilayer electrode, the time until the glass encapsulated OSC is degraded to 80% of its starting efficiency is enhanced from 86 h to approximately 4500 h compared to an OSC without an oxide interlayer.

An ultra‐thin MoO3–Au–Ag wetting layer metal electrode is investigated to eliminate present optical and electrical limitations of inverted top‐emitting OLEDs. Its high transmittance suppresses microcavity effects and the MoO3 hole injection layer compensates limited charge injection from the top contact. Overall, an extensive approach is presented to solve the key problems of top‐emitting OLEDs in general.

We discuss the electrical calcium test--a method to measure very small rates of water vapor permeation through barrier films with high throughput. The sensitivity range for our design is found to be 10(-5) to 15 g/(m(2) d). Moreover, a closer look at the importance of electrodes series resistance is taken: We show that permeation rates are underestimated if it is neglected. Taking this series resistance and Fickian diffusion into account not only the steady, but also the transient state of the permeation curve can be fitted. Using this approach, permeation barriers with different permeabilities are evaluated leading to water vapor transmission rates well comparable to coulometric measurements. The calcium layer morphology is investigated by atomic force microscopy measurements indicating microscopical inhomogeneities during degradation. Variations of electrode material and calcium layer thickness are carried out to examine their influence on the measured permeation. Additionally, optical and electrical calcium tests are compared. Small differences in the time dependence are observed and discussed.

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Highly transparent electrodes are demonstrated based on thermally evaporated calcium:silver blend thin-fi lms, which show unusually high transmission well above the expectations from bulk material properties and thin fi lm optics. These electrodes exhibit a low sheet resistance of 27.3 Ω/ٗ, combined with an extraordinarily high mean transmittance of 93.0% in the visible spectral range (σ dc /σ opt = 186.7), superior to the commonly used inorganic electrodes made from indium tin oxide (ITO). Additionally, the metal blend electrode is fl exible, showing a constant sheet resistance down to a bending radius of 10 mm and can be employed on top of organic devices without causing damage to the organic material. The spontaneously formed unique microstructure of a polycrystalline Ag network with randomly distributed nanoapertures, surrounded by a calcium shell, enables broadband transmittance enhancement due to amplifi ed plasmonic coupling. Consequently, topilluminated organic solar cells using such metal blend electrodes achieve a power conversion effi ciency of 7.2% (which defi nes a new record for top illuminated organic solar cells) and even exceed the effi ciency of similar bottomilluminated reference solar cells (6.9%) employing common ITO electrodes.

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Thin, transparent silver films sandwiched between dielectric layers are a versatile and high performance transparent electrode technology. Using direct laser interference patterning (DLIP), we are able to structure thin metal films by direct ablation in a fast, single step process. To achieve beneficial pattern and ablation properties, different sublayers of MoOx, Au, Al, Cr, or organics below the silver film and different laser power densities and pulse numbers are investigated. The resulting hexagonally periodic array of apertures shows improved transmittance and sheet resistance. For the best parameter set, the silver network contains little superfluous material at the joints and benefits from partial recrystallization, improving the conductivity. The nanostructured thin‐films have great potential to be combined with dielectric antireflection layers as transparent electrode for any thin‐film optoelectronic devices.