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In inkjet printing technology, one important factor influencing the printing quality and reliability of printed films is the interaction of the jetted ink with the substrate surface. This short-range interaction determines the wettability and the adhesion of the ink to the solid surface and is hence responsible for the final shape of the deposited ink. Here, we investigate wetting morphologies of inkjet-printed inks on patterned substrates by carefully designed experimental test structures and simulations. The contact angles, the surface properties, and drop shapes, as well as their influence on the device variability, are experimentally and theoretically analyzed. For the simulations, we employ the phase-field method, which is based on the free energy minimization of the two-phase system with the given wetting boundary conditions. Through a systematic investigation of printed drops on patterned substrates consisting of hydrophilic and hydrophobic areas, we report that the printed morphology is related not only to the designed layout and the drop volume but also to the printing strategy and the wettability. Furthermore, we show how one can modify the intrinsic wettability of the patterned substrates to enhance the printing quality and reliability. Based on the present findings, we cast light on the improvement of the fabrication quality of thin film transistors.

For on-chip oscillator phase noise characterization and monitoring a common technique is the measurement of the equivalent cycle-to-cycle jitter. In this brief we show that the quantization introduced to the recorded jitter by the measurement with a time-to-digital converter can be prohibitive for calculating the phase noise, especially at high oscillation frequencies and for spectrally pure oscillators. A second drawback of this method is that supply voltage noise can mask the phase noise due to intrinsic device noise. To avoid these limitations, we investigate an approach where the oscillator under test is compared to an identical replica. The resulting time difference measurements are introduced as delta jitter. The validity of the method is proven in simulation and measurement of an on-chip jitter measurement macro designed in 16nm FinFET CMOS technology. The measurement results indicate both robustness against quantization error and a self-canceling of correlated influences on phase noise in delta jitter measurements.

Memristors are an interesting novel class of devices for memory and beyond von Neumann computing. Besides classical CMOS technology, memristors can also be manufactured by additive printing techniques and hold great potential for printable neuromorphic circuits and memories. In this work, we report a fully inkjet-printed unipolar metal oxide memristor with a low forming voltage. The memristor is based on a sandwich-like Ag/ZnO/Ag structure. The device exhibits excellent performance parameters, such as high cycle-to-cycle and device-to-device uniformity and a long retention time of ${\geq } {10}^{{4}}$ s. Furthermore, the inkjet-printed memristor shows an exceptionally high $R_{\mathrm{OFF}} / R_{\mathrm{ON}}$ ratio of ${10}^{{7}}$ over 100 pulsed switching cycles.

The strongly growing interest in digitalizing society requires simple and reliable strain‐sensing concepts. In this work, a highly sensitive stretchable sensor is presented using a straightforward and scalable printing method. The piezoresistive sensor consists of conductive core–shell microspheres embedded in an elastomer. As the elastomer, ethylene vinyl acetate (EVA) is employed as an efficient and cost‐effective alternative compared to polydimethylsiloxane (PDMS). EVA allows for a significantly lower percolation threshold and low hysteresis compared with PDMS. Using 35 µm microspheres, a detection limit of 0.01% is achieved. When using 4 µm microspheres, the sensor shows a detection limit of 0.015% and electromechanical robustness against 1000 cycles of 0–1% strain. The stretchable strain sensor is successfully implemented as an impact sensor and a diaphragm expansion monitoring sensor. Fast (20 ms) and high‐resolution response as well as mechanical robustness to strain values greater than the linear working range of the sensor are demonstrated. The results of this research indicate the promising potential of employing conductive microspheres embedded in the EVA matrix for fast and precise strain detection applications. Using printing method, a stretchable strain sensor based on a composite of ethylene vinyl acetate as the elastic polymer and conductive microspheres as the filler is developed. The strain sensor is employed for impact sensing and diaphragm expansion monitoring. High‐resolution strain detection, fast response, and durability to overload strain are demonstrated.

Conductive polymers have been intensively investigated as materials for electrodes in flexible electronics due to their favorable biocompatibility and reliable electrochemical stability. Nevertheless, patterning of conductive polymers for the fabrication of devices and in various electronics applications confronts multifarious limitations and challenges. Here, we present a simple but efficient strategy to obtain conductive polymer microelectrodes via utilization of surface-tension-confined liquid patterns. This method shows universality for various oxidizers and conductive polymers, high resolution, stability, and favorable compatibility with different surfaces and materials. The developed method has been demonstrated for creating conductive polymer microelectrodes with a customized reaction process, defined geometry, and flexible substrates. The obtained microelectrodes were assembled into flexible capacitive sensors. Thus, the method realizes a facile approach to conductive polymer microelectrodes for flexible electronics, biomedical applications, human activity monitors, and electronic skin.

High-entropy nanomaterials exhibit exceptional mechanical, physical, and chemical properties, finding applications in many industries. Peroxidases are metalloenzymes that accelerate the decomposition of hydrogen peroxide. This study uses the high-entropy approach to generate multimetal oxide-based nanozymes with peroxidase-like activity and explores their application as sensors in ex vivobioassays. A library of 81 materials was produced using a coprecipitation method for rapid synthesis of up to 100 variants in a single plate. The A and B sites of the magnetite structure, (AA‘)(BB’B‘‘)2O4, were substituted with up to six different cations (Cu/Fe/Zn/Mg/Mn/Cr). Increasing the compositional complexity improved the catalytic performance; however, substitutions of single elements also caused drastic reductions in the peroxidase-like activity. A generalized linear model was developed describing the relationship between material composition and catalytic activity. Binary interactions between elements that acted synergistically or antagonistically were identified, and a single parameter, the mean interaction effect, was observed to correlate highly with catalytic activity, providing a valuable tool for the design of high-entropy-inspired nanozymes.