Pressure ( P ), temperature ( T ), and humidity ( H ) are physical key parameters of great relevance for various applications such as in distributed diagnostics, robotics, electronic skins, functional clothing, and many other Internet‐of‐Things (IoT) solutions. Previous studies on monitoring and recording these three parameters have focused on the integration of three individual single‐parameter sensors into an electronic circuit, also comprising dedicated sense amplifiers, signal processing, and communication interfaces. To limit complexity in, e.g., multifunctional IoT systems, and thus reducing the manufacturing costs of such sensing/communication outposts, it is desirable to achieve one single‐sensor device that simultaneously or consecutively measures P – T – H without cross‐talks in the sensing functionality. Herein, a novel organic mixed ion–electron conducting aerogel is reported, which can sense P – T – H with minimal cross‐talk between the measured parameters. The exclusive read‐out of the three individual parameters is performed electronically in one single device configuration and is enabled by the use of a novel strategy that combines electronic and ionic Seebeck effect along with mixed ion–electron conduction in an elastic aerogel. The findings promise for multipurpose IoT technology with reduced complexity and production costs, features that are highly anticipated in distributed diagnostics, monitoring, safety, and security applications.

In this article, the electroluminescence (EL) spectra of zinc oxide (ZnO) nanotubes/p-GaN light emitting diodes (LEDs) annealed in different ambients (argon, air, oxygen, and nitrogen) have been investigated. The ZnO nanotubes by aqueous chemical growth (ACG) technique on p-GaN substrates were obtained. The as-grown ZnO nanotubes were annealed in different ambients at 600°C for 30 min. The EL investigations showed that air, oxygen, and nitrogen annealing ambients have strongly affected the deep level emission bands in ZnO. It was concluded from the EL investigation that more than one deep level defect is involved in the red emission appearing between 620 and 750 nm and that the red emission in ZnO can be attributed to oxygen interstitials (Oi) appearing in the range from 620 nm (1.99 eV) to 690 nm (1.79 eV), and to oxygen vacancies (Vo) appearing in the range from 690 nm (1.79 eV) to 750 nm (1.65 eV). The annealing ambients, especially the nitrogen ambient, were also found to greatly influence the color-rendering properties and increase the CRI of the as - grown LEDs from 87 to 96.

Abstract:In this study, a potentiometric intracellular glucose biosensor was fabricated by immobilization of glucose oxidase on nanoflake ZnO. Nanoflake ZnO with a wall thickness around 200 nm was grown on the tip of a borosilicate glass capillary and used as a selective intracellular glucose biosensor for the measurement of glucose concentrations in human adipocytes and frog oocytes. The results showed a fast response within 4 s and a logarithmic linear glucose-dependent electrochemical potential difference over a wide range of glucose concentration (500 nM-10 mM). Our measurements of intracellular glucose were consistent with the values of intracellular glucose concentrations reported in the literature. The monitoring capability of the sensor was demonstrated by following the increase in the intracellular glucose concentration induced by insulin in frog oocytes. In addition, the nanoflake ZnO material provided 1.8 times higher sensitivity than previously used ZnO nanorods under the same conditions. Moreover, the fabrication method in our experiment is simple and the resulting nanosensor showed good performance in sensitivity, stability, selectivity, reproducibility, and anti-interference. All these results demonstrate that the nanoflake ZnO can provide a promising material for reliable measurements of intracellular glucose concentrations within single living cells. Key Words:Glucose oxidase (GOD), Intracellular, Potentiometric biosensor, Nanoflake ZnO, Nafion membrane Among all glucose biosensors, enzyme-based electrochemical glucose biosensors have been in the main focus of biosensor research because of their simplicity, relatively low cost, and high sensitivity [14][15][16]. The intrinsic advantages of electrochemical biosensors are their robustness, easy miniaturization, excellent detection limits, also with small sample volumes, and ability to be used in 3 turbid biofluids. In enzyme-based electrochemical biosensors, enzyme immobilization is regarded to be one of the most important issues. Since proper immobilization of enzymes on a suitable matrix and their stability are important factors in the fabrication of biosensors, the search of support materials that provide large surface area for higher enzyme loading and a compatible microenvironment that helps enzyme bioactivity is thus of great importance.Recently, zinc oxide (ZnO) nanostructures have attracted considerable interest in the applications of biosensors due to many advantages, including non-toxicity, bio-safety, excellent biological compatibility, high electron-transfer rates, enhanced analytical performance, increased sensitivity, and easy preparation [17][18][19][20][21][22]. In addition, it is important to note that ZnO is relatively stable around biological pH-values, which makes ZnO compatible with biological fluids and species [23].Furthermore, the high isoelectric point (IEP) of ZnO (IEP 9.5) makes it a good matrix for immobilizing low IEP acidic proteins or DNA by electrostatic interactions with high binding stability [24][25][26]. This wi...

No abstract

This study illustrates an innovative way to fabricate inkjet-printed tracks by sequential printing of Zn nanoparticle ink and curing ink for low temperature in situ chemical sintering. Employing chemical curing in place of standard sintering methods leads to the advantages of using flexible substrates that may not withstand the high thermal budgets of the standard methods. A general formulation engineering method is adopted to produce highly concentrated Zn ink which is cured by inkjet printing an over-layer of aqueous acetic acid which is the curing agent. The experimental results reveal that a narrow window of acid concentration of curing ink plays a crucial role in determining the electrical properties of the printed Zn nanoparticles. Highly conductive (~105 S m−1) and mechanically flexible printed Zn features are achieved. In addition, from systematic material characterization, we obtain an understanding of the curing mechanism. Finally, a touch sensor circuit is demonstrated involving all-Zn printed conductive tracks.