Plasma Polymerization Enabled Polymer/Metal-Oxide Hybrid Semiconductors for Wearable Electronics

From green chemistry to biomedicine: the sustainable symphony of cobalt oxide nanoparticles

Deciphering the importance of nanostructures in advanced technologies for a broad application spectrum has far-reaching implications for humans and the environment. Cost-effective, abundant cobalt oxide nanoparticles (NPs) are among the most attractive and extensively utilized materials in biomedical sciences due to their high chemical stability, and biocompatibility. However, the methods used to develop the NPs are hazardous for human health and the environment. This article precisely examines diverse green synthesis methods employing plant extracts and microbial sources, shedding light on their mechanism, and eco-friendly attributes with more emphasis on biocompatible properties accompanied by their challenges and avenues for further research. An in-depth analysis of the synthesized cobalt oxide NPs by various characterization techniques reveals their multifaceted functionalities including cytotoxicity, larvicidal, antileishmanial, hemolytic, anticoagulating, thrombolytic, anticancer and drug sensing abilities. This revelatory and visionary article helps researchers to contribute to advancing sustainable practices in nanomaterial synthesis and illustrates the potential of biogenically derived cobalt oxide NPs in fostering green and efficient technologies for biomedical applications.

Hydrogel Bioelectronics for Health Monitoring

Hydrogels are considered an ideal platform for personalized healthcare due to their unique characteristics, such as their outstanding softness, appealing biocompatibility, excellent mechanical properties, etc. Owing to the high similarity between hydrogels and biological tissues, hydrogels have emerged as a promising material candidate for next generation bioelectronic interfaces. In this review, we discuss (i) the introduction of hydrogel and its traditional applications, (ii) the work principles of hydrogel in bioelectronics, (iii) the recent advances in hydrogel bioelectronics for health monitoring, and (iv) the outlook for future hydrogel bioelectronics' development.

Mechanically Durable Organic/High-k Inorganic Hybrid Gate Dielectrics Enabled by Plasma-Polymerization of PTFE for Flexible Electronics

To achieve both the synergistic advantages of outstanding flexibility in organic dielectrics and remarkable dielectric/insulating properties in inorganic dielectrics, a plasma-polymerized hafnium oxide (HfO_x) hybrid (PPH-hybrid) dielectric is proposed. Using a radio-frequency magnetron cosputtering process, the high-k HfO_x dielectric is plasma-polymerized with polytetrafluoroethylene (PTFE), which is a flexible, thermally stable, and hydrophobic fluoropolymer dielectric. The PPH-hybrid dielectric with a high dielectric constant of 14.17 exhibits excellent flexibility, maintaining a leakage current density of ∼10^-8 A/cm² even after repetitive bending stress (up to 10000 bending cycles with a radius of 2 mm), whereas the HfO_x dielectric degrades to be leaky. To evaluate its practical applicability to flexible thin-film transistors (TFTs), the PPH-hybrid dielectric is applied to amorphous indium-gallium-zinc oxide (IGZO) TFTs as a gate dielectric. Consequently, the PPH-hybrid dielectric-based IGZO TFTs exhibit stable electrical performance under the same harsh bending cycles: a field-effect mobility of 16.99 cm²/(V s), an on/off current ratio of 1.15 × 10⁸, a subthreshold swing of 0.35 V/dec, and a threshold voltage of 0.96 V (averaged in nine devices). Moreover, the PPH-hybrid dielectric-based IGZO TFTs exhibit a reduced I-V hysteresis and an enhanced positive bias stress stability, with the threshold voltage shift decreasing from 4.99 to 1.74 V, due to fluorine incorporation. These results demonstrate that PTFE improves both the mechanical durability and electrical stability, indicating that the PPH-hybrid dielectric is a promising candidate for high-performance and low-power flexible electronics.

Recent Advances in Metal−Oxide Thin−Film Transistors: Flexible/Stretchable Devices, Integrated Circuits, Biosensors and Neuromorphic Applications

Thin−film transistors using metal oxides have been investigated extensively because of their high transparency, large area, and mass production of metal oxide semiconductors. Compatibility with conventional semiconductor processes, such as photolithography of the metal oxide offers the possibility to develop integrated circuits on a larger scale. In addition, combinations with other materials have enabled the development of sensor applications or neuromorphic devices in recent years. Here, this paper provides a timely overview of metal−oxide−based thin−film transistors focusing on emerging applications, including flexible/stretchable devices, integrated circuits, biosensors, and neuromorphic devices. This overview also revisits recent efforts on metal oxide−based thin−film transistors developed with high compatibility for integration to newly reported applications.

Conductive Polymer-Assisted Metal Oxide Hybrid Semiconductors for High-Performance Thin-Film Transistors

Metal oxide semiconductors doped with additional inorganic cations have insufficient electron mobility for next-generation electronic devices so strategies to realize the semiconductors exhibiting stability and high performance are required. To overcome the limitations of conventional inorganic cation doping to improve the electrical characteristics and stability of metal oxide semiconductors, we propose solution-processed high-performance metal oxide thin-film transistors (TFTs) by incorporating polyaniline (PANI), a conductive polymer, in a metal oxide matrix. The chemical interaction between the metal oxide and PANI demonstrated that the defect sites and crystallinity of the semiconductor layer are controllable. In addition, the change in oxygen-related chemical bonding of PANI-doped indium oxide (InO_x) TFTs induces superior electrical characteristics compared to pristine InO_x TFTs, even though trace amounts of PANI are doped in the semiconductor. In particular, the average field-effect mobility remarkably enhanced from 15.02 to 26.58 cm² V^-1 s^-1, the on/off current ratio improved from 10⁸ to 10⁹, and the threshold voltage became close to 0 V actually from -7.9 to -1.4 V.

Mechanochemical and Thermal Treatment for Surface Functionalization to Reduce the Activation Temperature of In-Ga-Zn-O Thin-film Transistors

Amorphous indium-gallium-zinc oxide (a-IGZO) films, which are widely regarded as a promising material for the channel layer in thin-film transistors (TFTs), require a relatively high thermal annealing temperature to achieve switching characteristics through the formation of metal-oxygen (M-O) bonding (i.e., the activation process). The activation process is usually carried out at a temperature above 300 °C; however, achieving activation at lower temperatures is essential for realizing flexible display technologies. Here, a facile, low-cost, and novel technique using cellophane tape for the activation of a-IGZO films at a low annealing temperature is reported. In terms of mechanochemistry, mechanical pulling of the cellophane tape induces reactive radicals on the a-IGZO film surface, which can give rise to improvements in the properties of the a-IGZO films, leading to an increase in the number of M-O bonds and the carrier concentration via radical reactions, even at 200 °C. As a result, the a-IGZO TFTs, compared to conventionally annealed a-IGZO TFTs, exhibited improved electrical performances, such as mobility, on/off current ratio, and threshold voltage shift (under positive bias temperature and negative bias temperature stress for 10,000 s at 50 °C) from 8.25 to 12.81 cm²/(V·s), 2.85 × 10⁷ to 1.21 × 10⁸, 6.81 to 3.24 V, and -6.68 to -4.93 V, respectively.

Hybrid Polymer/Metal Oxide Thin Films for High Performance, Flexible Transistors

Metal oxides (MOs) have garnered significant attention in a variety of research fields, particularly in flexible electronics such as wearable devices, due to their superior electronic properties. Meanwhile, polymers exhibit excellent mechanical properties such as flexibility and durability, besides enabling economic solution-based fabrication. Therefore, MO/polymer nanocomposites are excellent electronic materials for use in flexible electronics owing to the confluence of the merits of their components. In this article, we review recent developments in the synthesis and fabrication techniques for MO/polymer nanocomposite-based flexible transistors. In particular, representative MO/polymer nanocomposites for flexible and transparent channel layers and gate dielectrics are introduced and their electronic properties-such as mobilities and dielectric constant-are presented. Finally, we highlight the advances in interface engineering and its influence on device electronics.

Evidence of Cu(I) Coupling with Creatinine Using Cuprous Nanoparticles Encapsulated with Polyacrylic Acid Gel-Cu(II) in Facilitating the Determination of Advanced Kidney Dysfunctions

An electrochemical-based sensor created for creatinine detection has been developed for early point-of-care (POC) of diagnosis of renal illnesses. Useful information for the preventive diagnosis and clinical treatments of congenital disorders of creatinine mechanism, advanced liver and kidney diseases, and renal dysfunction can be obtained by the noninvasive evaluation of the creatinine levels in urine. The direct detection of creatinine can be achieved using the modified nanocomposite of cuprous nanoparticles encapsulated by polyacrylic acid (PAA) gel-Cu(II) fabricating on a screen-printed carbon electrode. Here, we report that the degree of kidney dysfunction failure can be determined by an amount of Cu(I) bound with the creatinine through the adsorptive mechanism on the modified electrode. Under cyclic voltammetry scans, the amount of creatinine was measured from the adsorptive signals of the redox peak current identifying the Cu(I)-creatinine complex with a natural logarithm of the creatinine concentration ranging from 200 μM to 100 mM. For this detection range, the theoretical calculation was postulated to describe experimental behaviors of the adsorptive mechanism as creatinine diffused to adsorb on the composite-modified electrode to reduce oxidized copper nanoparticles and transformed to Cu(II)-creatinine complexes. Interestingly, there was evidence that anodic peak potentials had been reduced in magnitudes and shifted negatively by natural logarithm during the formation of the Cu(I)-creatinine complex. For practical usage in POC technology, the creatinine detection in interference was carried out using differential pulse voltammetry to solely determine faradaic currents of creatinine-copper formation. With the interference of urea, glucose, ascorbic acid, glycine, and uric acid in artificial urine, the sensor showed promising results of the interference-free determination with 99.4% sensitivity efficiency, whereas for human urine interference, this sensor showed 85% sensitivity efficiency in detecting creatinine. This shows that this composite-modified sensor (PAA gel-Cu(II)/Cu₂O NPs) has great potential for use in the next-generation devices for creatinine sensing to determine the progression in kidney dysfunctions.