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In today's digital world, the demand for computer security and system reliability is a crucial element. Monitoring the CPU temperature during operation provides valuable insights but is currently limited to the embedded on‐chip sensors. The implementation of an extra security layer based on temperature monitoring can detect anomalies in an early stage, identify malware, and help mitigate attacks. The approach of integrating more on‐chip temperature sensors into the silicon is avoided due to space, power limitations, and cost constraints. However, the field of printed electronics and sensor technology has recently seen significant progress. This is the first work that introduces a fully‐printed temperature sensor array integrated onto the cooling unit of a CPU. It offers a novel approach for the practical implementation of such sensors into an operational computer system. The present sensor array, consisting of 396 sensor pixels, detects local hotspots induced by the underneath CPU cores, leading to an individual thermal fingerprint. This unique method paves the way for addressing pivotal elements of computer security, as deviations from expected thermal behavior can signal malicious activities. Additionally, this innovation facilitates reliability optimization. The detailed thermal map garnered provides insights into which cores are subjected to significant stress over time. [ABSTRACT FROM AUTHOR]

In this study, a room-temperature ammonia gas sensor using a ZnO and reduced graphene oxide (rGO) composite is developed. The sensor fabrication involved the innovative application of reverse offset and electrostatic spray deposition (ESD) techniques to create a ZnO/rGO sensing platform. The structural and chemical characteristics of the resulting material were comprehensively analyzed using XRD, FT-IR, FESEM, EDS, and XPS, and rGO reduction was achieved via UV–ozone treatment. Electrical properties were assessed through I–V curves, demonstrating enhanced conductivity due to UV–ozone treatment and improved charge mobility from the formation of a ZnO–rGO heterojunction. Exposure to ammonia gas resulted in increased sensor responsiveness, with longer UV–ozone treatment durations yielding superior sensitivity. Furthermore, response and recovery times were measured, with the 10 min UV–ozone-treated sensor displaying optimal responsiveness. Performance evaluation revealed linear responsiveness to ammonia concentration with a high R2 value. The sensor also exhibited exceptional selectivity for ammonia compared to acetone and CO gases, making it a promising candidate for ammonia gas detection. This study shows the outstanding performance and potential applications of the ZnO/rGO-based ammonia gas sensor, promising significant contributions to the field of gas detection. [ABSTRACT FROM AUTHOR]

In this study, a room-temperature ammonia gas sensor using a ZnO and reduced graphene oxide (rGO) composite is developed. The sensor fabrication involved the innovative application of reverse offset and electrostatic spray deposition (ESD) techniques to create a ZnO/rGO sensing platform. The structural and chemical characteristics of the resulting material were comprehensively analyzed using XRD, FT-IR, FESEM, EDS, and XPS, and rGO reduction was achieved via UV–ozone treatment. Electrical properties were assessed through I–V curves, demonstrating enhanced conductivity due to UV–ozone treatment and improved charge mobility from the formation of a ZnO–rGO heterojunction. Exposure to ammonia gas resulted in increased sensor responsiveness, with longer UV–ozone treatment durations yielding superior sensitivity. Furthermore, response and recovery times were measured, with the 10 min UV–ozone-treated sensor displaying optimal responsiveness. Performance evaluation revealed linear responsiveness to ammonia concentration with a high R2 value. The sensor also exhibited exceptional selectivity for ammonia compared to acetone and CO gases, making it a promising candidate for ammonia gas detection. This study shows the outstanding performance and potential applications of the ZnO/rGO-based ammonia gas sensor, promising significant contributions to the field of gas detection.

Abstract With further digitalization and automation, new applications fields require new solutions and sensors. Healthcare, soft robotics, and battery research are only three examples striving for sensor solutions capable of measuring the spatial and temporal temperature distribution of surfaces. This requires the deposition of multiple sensor pixels with a high spatial resolution on potentially flexible substrates. Printing technologies are well suited to fulfill the associated requirements of quality, speed, feature size, and costs. Combining screen printing and aerosol jet printing allows for fast large‐scale processing and when needed high‐precision fabrication for small features. The presented high‐density temperature sensor array provides 625 sensor pixels with a size of 60×60 µm2, evenly distributed over an area of 12×12 mm2. The sensor is operated without encapsulation between 5 and 90 °C showing an average deviation of less than 0.5 °C. The sensor stack consists of a bottom and top electrode sandwiching a carbon black based thermistor layer. The material shows a strong negative‐temperature‐coefficient (NTC) effect with a sensitivity of 3.6 % °C−1 at 5 °C. As an application example, the temperature profile induced by a laser beam is mapped with the temperature sensor array.

Ultrafast laser patterning is an essential technology for the low-cost and large area production of flexible Organic Electronic (OE) devices, such as Organic Photovoltaics (OPVs). In order to unleash the potential of ultrafast laser processing to perform the selective and high precision removal of complex multilayers from printed OPV stacks without affecting the underlying nanolayers, it is necessary to optimize its parameters for each nanolayer combination. In this work, we developed an efficient on-the-fly picosecond (ps) laser scribing process (P1, P2 and P3) using single wavelength and single step/pass for the precise and reliable in-line patterning of Roll-to-Roll (R2R) slot-die-coated nanolayers. We have investigated the effect of the key process parameters (pulse energy and overlap) on the patterning quality to obtain high selectivity on the ablation of each individual nanolayer. Finally, we present the implementation of the ultrafast laser patterning process in the manufacturing of fully R2R printed flexible semitransparent OPV modules with a 3.4% power conversion efficiency and 91% Geometric Fill Factor (GFF). [ABSTRACT FROM AUTHOR]

Ultrafast laser patterning is an essential technology for the low-cost and large area production of flexible Organic Electronic (OE) devices, such as Organic Photovoltaics (OPVs). In order to unleash the potential of ultrafast laser processing to perform the selective and high precision removal of complex multilayers from printed OPV stacks without affecting the underlying nanolayers, it is necessary to optimize its parameters for each nanolayer combination. In this work, we developed an efficient on-the-fly picosecond (ps) laser scribing process (P1, P2 and P3) using single wavelength and single step/pass for the precise and reliable in-line patterning of Roll-to-Roll (R2R) slot-die-coated nanolayers. We have investigated the effect of the key process parameters (pulse energy and overlap) on the patterning quality to obtain high selectivity on the ablation of each individual nanolayer. Finally, we present the implementation of the ultrafast laser patterning process in the manufacturing of fully R2R printed flexible semitransparent OPV modules with a 3.4% power conversion efficiency and 91% Geometric Fill Factor (GFF).

Inorganic semiconductors have the potential features to enhance the stability and performance of printed electronic devices. In this work, we present a microcantilever ($\mu \text{C}$) printed device by using zinc oxide (ZnO) and silver nanoparticles (AgNP) ink. Two types of devices have been fabricated on silicon wafers using two methods: (i) the ZnO ink is printed between two $\mu \text{C}$ printed AgNP electrodes separated within a sub- $5~\mu \text{m}$ gap (ii) the ZnO ink have been drop-casted between two $\mu \text{C}$ printed AgNP electrodes. Therefore the first type of devices is a fully printed structure. The measurements of both devices show distinct electrical aspects corresponding to the different additive fabrication approach. Furthermore, the fully printed Schottky diode exhibits a remarkable high on/off current ratio of $1.85\times 10^{{5}}$ at room temperature with a barrier height of 0.49 eV and series resistance of 594 $\text{k}\Omega $. [ABSTRACT FROM AUTHOR]

Abstract: Dielectric mirrors are wavelength‐selective mirrors which are based on thin film interference effects. Their optical band can precisely be adjusted in width, position, and reflectance by the refractive index of the applied materials, the layers' thicknesses, and the amount of deposited layers. Nowadays, they are a well‐known light management tool for efficiency enhancement in, for example, semitransparent organic solar cells (OSCs) and light guiding in organic light‐emitting diodes (OLEDs). However, most of the dielectric mirrors are still fabricated by lab‐scale techniques such as spin‐coating or physical vapor deposition under vacuum. Large‐scale, fully printed (maximum 20 × 20 cm2) dielectric mirrors with adjustable reflectance characteristics are fabricated, using temperatures of maximum 50 °C and alcohol‐based inks. According to the moderate processing conditions they can be easily deposited not only on rigid glass substrates but also on flexible foils. They show high stability against humidity, light irradiation, and temperature, positioning themselves as good candidates for applications in OLEDs and OSCs. Eventually, by simulations and experiments it is verified that a moderate degree of variations in layer thickness and surface roughness can suppress side interference fringes, while not impacting the main transmittance minimum or the main reflection maximum, respectively. [ABSTRACT FROM AUTHOR]

All-polymer, semi-transparent, three-layer-dielectric (3L) organic field effect transistors (OFETs) are fabricated on polyethylene terephthalate plastic substrate, using high-throughput printing techniques. Analog small-signal characteristics of the 3L OFET are presented and are compared against the previous version of this technology, which was based on a single-layer dielectric and a metal gate electrode. The 3L transistor withstands 50 V, can continuously drive 50 μA/mm, reaches an excellent intrinsic-gain ( A v0 ) of 43 dB, an equivalent mobility of 0.85 cm 2 /V, and a transit frequency ( f T ) of 68 kHz, well suited for applications such as driving printed piezoelectric loudspeakers and flexible audio systems. The effects of the relaxor-ferroelectric high-k layer in the 3L stack on the gate capacitance, g m , and A v0 are measured in the frequency domain. In addition, it is observed that PEDOT:PSS makes a better interface with polymer dielectric comparing to copper particle ink. Five-hour small- and large-signal bias stress tests are performed. A novel direct A v0 measurement technique, and an improved transconductance extraction method are also presented. [ABSTRACT FROM AUTHOR]

An electrochemical amperometric nitrogen dioxide sensor with solid polymer electrolyte has been fabricated on flexible substrate by screen printing technology. The sensor concept is based on semi-planar, three electrode topology that enables to produce low power, high performance, thin and selective device that can be implemented on PET and/or Kapton foil. In addition, it has been demonstrated that the new platform of the electrochemical NO 2 sensor can be manufactured without metallic electrodes which is very important from the point of view of environments. The sensor shows linear response in the range of 0-10 ppm, fast response/recovery times (70/60 s, respectively) and sensitivity 590 nA/ppm. All sensor layers have been prepared by low cost mass production technology presented by screen printing technique. This approach has allowed to fabricate flexible, extremely low cost electrochemical NO 2 sensors for environmental monitoring. [ABSTRACT FROM AUTHOR]

This letter presents a novel approach to fully-printed phase shifters for electronically steering the beam of a phased array antenna at S-Band. The phased array consists of four microstrip patch antenna elements and phase shifters, as well as a four-to-one feeding network. As key components in the circuit, the phase shifters are provided with a microstrip loaded-line topology, equipping fully-printed metal-insulator-metal (MIM) varactors with low-temperature sintered BST composite thick films between the top and bottom silver electrodes. Furthermore, a simple biasing concept is implemented for controlling the phase shifter. The fully-printed, low-cost phase shifters achieved a phase shift of 274^\circ and a FoM of 37.3^\circ/dB at 3 GHz. The length of the phase shifters was 0.2\lambda, where their phase shift versus length resulted in a 14.4^\circ/mm measurement, outperforming all previously reported phase shifters based on fully-printed low-temperature sintered BST thick film. The beam-scanning range of the four-antenna element array was \pm30^\circ. [ABSTRACT FROM PUBLISHER]

Dielectric mirrors based on bilayers of polystyrene- block-poly(ethylene- ran-butylene)- block-polystyrene (SEBS) and poly(vinyl alcohol) (PVA)-zirconium dioxide (ZrO 2 ) nanocomposites are fabricated for vapor sensing. When exposed to specific solvent vapor, the layers of dielectric mirrors can gradually swell and cause a red-shift of the reflection band. Because PVA solely responds to water and SEBS is sensitive to several different types of organic solvents, the mirrors can respond to a large variety of solvents. The dual-functional hydrophilic ZrO 2 nanoparticles are introduced to not only enlarge the refractive index contrast but also increase the permeability. Time-resolved measurements show that mirrors with nanoparticles have a significantly faster response than those without nanoparticles. Moreover, the dependence on relative humidity is studied for representative solvents, and several types of solvents are selected to show the dependence on the solvent-polymer interaction parameters at typical relative humidity, which allows one to predict the responsivity and selectivity of the sensors.

This paper investigates with a statistical analysis the issue of performance reproducibility and optimization in fully inkjet-printed organic photodetectors on flexible substrates. The most crucial process step to obtain reproducible, well performing devices with a high process yield turns out to be the printing of the thin polyethylenimine interlayer used as a surface modifier for the bottom electrode. Controlling solution composition and deposition parameters for this layer, a 57 nA cm -2 mean reverse dark current was achieved, with an outstanding standard deviation as low as 15 nA cm -2 , with dramatic improvements in process yield (from less than 20% to over 90%). Device performance in terms of dark currents, EQE (from 50% up to 90% at 525 nm, depending on process), and rectification (ratio between forward current and reverse current over 10 4 and reaching 10 5 in the best cases) is among the best for fully printed detectors. Furthermore, the importance of relative humidity control in the deposition environment during the interlayer printing on device characteristics is reported, indicating the processing conditions optimal for scaling to mass manufacturing. The overall interlayer optimization approach was applied to a process using widely adopted materials in the organic optoelectronics field, and thus retains relevance on a broad range.

Fully printed thin film transistors (TFT) based on poly(9,9-di-n-dodecylfluorene) (PFDD) wrapped semiconducting single walled carbon nanotube (SWCNT) channels are fabricated by a practical route that combines roll-to-roll (R2R) gravure and ink jet printing. SWCNT network density is easily controlled via ink formulation (concentration and polymer:CNT ratio) and jetting conditions (droplet size, drop spacing, and number of printed layers). Optimum inkjet printing conditions are established on Si/SiO 2 in which an ink consisting of 6:1 PFDD:SWCNT ratio with 50 mg L -1 SWCNT concentration printed at a drop spacing of 20 μm results in TFTs with mobilities of ∼25 cm 2 V -1 s -1 and on-/off-current ratios > 10 5 . These conditions yield excellent network uniformity and are used in a fully additive process to fabricate fully printed TFTs on PET substrates with mobility values > 5 cm 2 V -1 s -1 (R2R printed gate electrode and dielectric; inkjet printed channel and source/drain electrodes). An inkjet printed encapsulation layer completes the TFT process (fabricated in bottom gate, top contact TFT configuration) and provides mobilities > 1 cm 2 V -1 s -1 with good operational stability, based on the performance of an inverter circuit. An array of 20 TFTs shows that most have less than 10% variability in terms of threshold voltage, transconductance, on-current, and subthreshold swing.