Flexible Organic Thin Film Transistors Incorporating a Biodegradable CO2-Based Polymer as the Substrate and Dielectric Material

Highly parallel and ultra-low-power probabilistic reasoning with programmable gaussian-like memory transistors

Probabilistic inference in data-driven models is promising for predicting outputs and associated confidence levels, alleviating risks arising from overconfidence. However, implementing complex computations with minimal devices still remains challenging. Here, utilizing a heterojunction of p- and n-type semiconductors coupled with separate floating-gate configuration, a Gaussian-like memory transistor is proposed, where a programmable Gaussian-like current-voltage response is achieved within a single device. A separate floating-gate structure allows for exquisite control of the Gaussian-like current output to a significant extent through simple programming, with an over 10000 s retention performance and mechanical flexibility. This enables physical evaluation of complex distribution functions with the simplified circuit design and higher parallelism. Successful implementation for localization and obstacle avoidance tasks is demonstrated using Gaussian-like curves produced from Gaussian-like memory transistor. With its ultralow-power consumption, simplified design, and programmable Gaussian-like outputs, our 3-terminal Gaussian-like memory transistor holds potential as a hardware platform for probabilistic inference computing.

Melanins as Sustainable Resources for Advanced Biotechnological Applications

Melanins are a class of biopolymers that are widespread in nature and have diverse origins, chemical compositions, and functions. Their chemical, electrical, optical, and paramagnetic properties offer opportunities for applications in materials science, particularly for medical and technical uses. This review focuses on the application of analytical techniques to study melanins in multidisciplinary contexts with a view to their use as sustainable resources for advanced biotechnological applications, and how these may facilitate the achievement of the United Nations Sustainable Development Goals.

Sensors Made of Natural Renewable Materials: Efficiency, Recyclability or Biodegradability-The Green Electronics

Nowadays, sensor devices are developing fast. It is therefore critical, at a time when the availability and recyclability of materials are, along with acceptability from the consumers, among the most important criteria used by industrials before pushing a device to market, to review the most recent advances related to functional electronic materials, substrates or packaging materials with natural origins and/or presenting good recyclability. This review proposes, in the first section, passive materials used as substrates, supporting matrixes or packaging, whether organic or inorganic, then active materials such as conductors or semiconductors. The last section is dedicated to the review of pertinent sensors and devices integrated in sensors, along with their fabrication methods.

Biodegradable Materials and Green Processing for Green Electronics

There is little question that the "electronic revolution" of the 20th century has impacted almost every aspect of human life. However, the emergence of solid-state electronics as a ubiquitous feature of an advanced modern society is posing new challenges such as the management of electronic waste (e-waste) that will remain through the 21st century. In addition to developing strategies to manage such e-waste, further challenges can be identified concerning the conservation and recycling of scarce elements, reducing the use of toxic materials and solvents in electronics processing, and lowering energy usage during fabrication methods. In response to these issues, the construction of electronic devices from renewable or biodegradable materials that decompose to harmless by-products is becoming a topic of great interest. Such "green" electronic devices need to be fabricated on industrial scale through low-energy and low-cost methods that involve low/non-toxic functional materials or solvents. This review highlights recent advances in the development of biodegradable materials and processing strategies for electronics with an emphasis on areas where green electronic devices show the greatest promise, including solar cells, organic field-effect transistors, light-emitting diodes, and other electronic devices.

High-k Polymer Nanocomposite Materials for Technological Applications

Understanding the properties of small molecules or monomers is decidedly important. The efforts of synthetic chemists and material engineers must be appreciated because of their knowledge of how utilize the properties of synthetic fragments in constructing long-chain macromolecules. Scientists active in this area of macromolecular science have shared their knowledge of catalysts, monomers and a variety of designed nanoparticles in synthetic techniques that create all sorts of nanocomposite polymer stuffs. Such materials are now an integral part of the contemporary world. Polymer nanocomposites with high dielectric constant (high-k) properties are widely applicable in the technological sectors including gate dielectrics, actuators, infrared detectors, tunable capacitors, electro optic devices, organic field-effect transistors (OFETs), and sensors. In this short colloquy, we provided an overview of a few remarkable high-k polymer nanocomposites of material science interest from recent decades.

Various Coating Methodologies of WO3 According to the Purpose for Electrochromic Devices

Solution-processable electrochromic (EC) materials have been investigated widely for various applications, such as smart windows, reflective displays, and sensors. Among them, tungsten trioxide (WO₃) is an attractive material because it can form a film via a solution process and relative low temperature treatment, which is suitable for a range of substrates. This paper introduces the slot-die and electrostatic force-assisted dispensing (EFAD) printing for solution-processable methods of WO₃ film fabrication. The resulting films were compared with WO₃ films prepared by spin coating. Both films exhibited a similar morphology and crystalline structure. Furthermore, three different processed WO₃ film-based electrochromic devices (ECDs) were prepared and exhibited similar device behaviors. In addition, large area (100 cm²) and patterned ECDs were fabricated using slot-die and EFAD printing. Consequently, slot-die and EFAD printing can be used to commercialize WO₃ based-ECDs applications, such as smart windows and reflective displays.

Development of cost effective metal oxide semiconductor based gas sensor over flexible chitosan/PVP blended polymeric substrate

In the present work, biodegradable and flexible chitosan/polyvinylpyrrolidone (CHP) polymeric substrate was fabricated by solvent casting method. This is a novel demonstration of the combination of natural polymer (chitosan) and synthetic polymer (PVP) for next-generation semiconductor device applications. The ZnO thin films were successfully synthesized on these polymeric substrates by facile drop-casting method for gas sensing applications. The hydrogen gas sensing properties of ZnO deposited on the polymeric substrate and SiO₂ substrate show similar performance. The structural, morphological, optical, thermal, and tensile strength of the CHP substrate were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible spectroscopy, Derivative thermogravimetric analysis (DTG), and Universal testing machine (UTM), respectively. Our study suggests that the biodegradable CH/PVP flexible polymeric substrate provides a new way for the implementation of an eco-friendly green substrate in numerous electronic device applications.

When Flexible Organic Field-Effect Transistors Meet Biomimetics: A Prospective View of the Internet of Things

The emergence of flexible organic electronics that span the fields of physics and biomimetics creates the possibility for increasingly simple and intelligent products for use in everyday life. Organic field-effect transistors (OFETs), with their inherent flexibility, light weight, and biocompatibility, have shown great promise in the field of biomimicry. By applying such biomimetic OFETs for the internet of things (IoT) makes it possible to imagine novel products and use cases for the future. Recent advances in flexible OFETs and their applications in biomimetic systems are reviewed. Strategies to achieve flexible OFETs are individually discussed and recent progress in biomimetic sensory systems and nervous systems is reviewed in detail. OFETs are revealed to be one of the best systems for mimicking sensory and nervous systems. Additionally, a brief discussion of information storage based on OFETs is presented. Finally, a personal view of the utilization of biomimetic OFETs in the IoT and future challenges in this research area are provided.

Hysteresis Reduction for Organic Thin Film Transistors with Multiple Stacked Functional Zirconia Polymeric Films

We show that transfer hysteresis for a pentacene thin film transistor (TFT) with a low-temperature solution-processed zirconia (ZrOx) gate insulator can be remarkably reduced by modifying the ZrOx surface with a thin layer of crosslinked poly(4-vinylphenol) (c-PVP). Pentacene TFTs with bare ZrOx and c-PVP stacked ZrOx gate insulators were fabricated, and their hysteresis behaviors compared. The different gate insulators exhibited no significant surface morphology or capacitance differences. The threshold voltage shift magnitude decreased by approximately 71% for the TFT with the c-PVP stacked ZrOx gate insulator compared with the bare ZrOx gate insulator, with 0.75 ± 0.05 and 0.22 ± 0.03 V threshold voltage shifts for the bare ZrOx and c-PVP stacked ZrOx gate insulators, respectively. The hysteresis reduction was attributed to effectively covering hysteresis-inducing charge trapping sites on ZrOx surfaces.

Disposable Fluidic Devices of Bionanochannels for Enzymatic Monitoring and Energy Harvesting

Nature produces a plethora of nanochannels to carry out highly complex biological tasks in a sophisticated manner. There have been several studies to understand the characteristics of these channels; however, efforts to apply them for technological advancements are still scarce. Here, we have demonstrated that the fluidic channels of biomaterials can be harvested as nanofluidic devices to produce energy from enzymatic chemical reactions. The bionanochannel-based nanofluidic devices exhibit various nanofluidic phenomena like surface-charged-governed ionic conductivity and development of the transmembrane potential. The mobility of ions in the hydrated bionanochannels are found to be higher than that of bulk water. The cation-selective nature of the biochannels was also exploited to harvest a continuous supply of power up to 74 mW m^-2 for 3 h from the enzymatic decomposition of urea. The transmembrane potential across the biochannels was also explored for label-free electrical monitoring of the enzymatic reaction inside the biological medium. Electrical monitoring on the kinetics of urease at different reaction temperatures suggested that inside biological medium the reaction goes through a pathway of lower activation energy (31.1 kJ) than that in the bulk environment (34.1 kJ). Enzyme urease was found to be more sustainable in bionanochannels than in glass vials.