The paper addresses the through silicon via (TSV) filling using electrochemical deposition (ECD) of copper. The impact of seed layer nature on filling ratio and void formation will be discussed with respect to via diameter and via depth. Based on the Spherolyte Cu200 the electrolyte for the copper electrochemical deposition was modified for good filling behavior. Thermomechanical modeling and simulation was performed for reliability assessment

Low efficiencies of soluble blue emitter materials remain a major issue in the development of printed organic lightemitting devices. n-Alkylated carbazoles or sterically demanding ortho-substituted diphenylamines were employed as donor elements to increase solubility and to preserve blue emission of thermally activated delayed fluorescence (TADF) donor−acceptor−donor emitters employing a p-bis(phenylsulfonyl)benzene acceptor described in the literature. The soluble molecules exhibited increased steric hindrance of the amine donors and a small ΔE ST as low as 0.32 eV. Thermally activated delayed fluorescence occurs, and photoluminescence quantum yields of ≤82% were achieved. Application of these TADF molecules in solution-processed organic light-emitting diodes resulted in high brightnesses of ≤10000 cd/m 2 , current efficiencies of ≤9.5 cd/A, and external quantum efficiencies of ≤8.5%, while retaining deep blue emission ranging from 466 to 436 nm with color coordinates low as CIE y = 0.08.

The use of biocompatible and biodegradable materials in optoelectronics will enable the development of promising applications in the field of healthcare and environmental sensors as well as a more sustainable production of technology. Here, we present light-emitting electrochemical cells which utilize the biodegradable polymer poly­(lactic-co-glycolic acid) (PLGA) to promote ionic conductivity in the active layer of light-emitting electrochemical cells. The device performance was analyzed in terms of the volume fraction of PLGA in the active layer blend as well as with respect to three different lactic:glycolic monomer ratios (85:15, 75:25, 65:35). In all three cases, adding PLGA to the active layer leads to an improvement of the turn-on voltage of up to 2 V compared to reference devices without PLGA. This can be attributed to an increase in ionic conductivity, which was determined by impedance spectroscopy. Increasing the relative amount of PLGA in the active layer shows that the improvement is ultimately limited by poor intermixing with the polymeric emitter as observed by fluorescent microscopy. The best devices achieved turn-on voltages of 4.1 V and a maximum luminance of 3800 cd m–2 at 7.1 V.

In this work, we demonstrate the use of the biodegradable polymer polycaprolactone (PCL) as the ion solvating polymer in solution-processed light-emitting electrochemical cells (LEC). We show that the inclusion of PCL in the active layer yields higher ionic conductivities and thus contributes to a rapid formation of the dynamic p-i-n junction and reduction of operating voltages. PCL shows no phase separation with the emitter polymer and reduces film roughness. The devices show light-emission at voltages as low as 3.2 V and lifetimes on the order of 30 h operating above 150 cd m−2 with turn-on times <20 s and current and luminous efficacies of 3.2 Cd A−1 and 1.5 lm W−1 respectively.

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We report the synthesis and characterization of a cross-linkable, cinnamic acid functionalized, hole-transporting polyfluorene–triarylamine (PF–PTAA) copolymer. Irradiation with light induces [2 + 2] cycloaddition and renders thin films of this polymer insoluble. Spin-coated films of the polymer and their light-induced cross-linking were investigated by atomic force and electron microscopy. In a proof-of-principle multilayer OLED device the polymer was applied as hole-transport layer (HTL) with commercially available F8BT as emitting layer (EML). Compared to the reference device without HTL we observe a significant increase in OLED performance. These results promise progress in cost-effective large area fabrication of polymer-based multilayer OLEDs with superior performance.

Solution processed biomaterials are required for the active component to develop printed biodegradable and biocompatible optoelectronic devices. Ideal film formation is crucial for the fabrication of multilayer thin film sandwich devices. We report on the characterization of thin films of the riboflavin-derived biomaterial riboflavin tetrabutyrate and its utilization in an organic light-emitting diode. We show that the nonsolution processable precursor can form homogeneous and smooth films with the addition of tailored side groups that change its solubility. We demonstrate by grazing incidence wide-angle X-ray scattering that this chemical derivative reduces the crystallinity and enhances emission, likely by suppressing π–π stacking interactions. Organic light-emitting diodes with a poly­(9-vinylcarbazole)–emissive riboflavin tetrabutyrate bilayer structure yield a maximum luminance of 10 cd/m2 and external quantum efficiency of 0.02% with a 640 nm peak orange exciplex emission. External quantum efficiency measurements of a photodiode affirm the exciplex formation.

Integration of light management solutions relying on biodegradable materials in organic light‐emitting devices could assist the development of sustainable light sources or conformable and wearable display technology. Using industrially relevant processing techniques, it is shown that microlens arrays can be seamlessly integrated into flexible and biodegradable cellulose diacetate substrates to facilitate extraction of the trapped substrate modes in light‐emitting electrochemical cells. The substrates are patterned for light extraction and optimized for scalable printing processes in a single step by thermally embossing microlenses with polydimethylsiloxane molds on one substrate surface and simultaneous flattening of the other. Furthermore, by implementing the biopolymer substrate with microlens arrays, the total volume fraction of biodegradable materials in the microlense equipped device is 99.94%. The embossed microstructures on the biopolymer substrates are investigated by means of scanning electron microscopy and the angular light extraction profile of the devices is measured and compared to ray tracing simulations. Light‐emitting electrochemical cells with integrated microlens array substrates achieve an efficiency enhancement factor of 1.45, exceeding conventional organic light‐emitting diodes on glass substrates with laminated microlens arrays (enhancement factor of 1.23).