PEDOT: PSS thermoelectric generators printed on paper substrates

Flexible electronics is a field gathering a growing interest among researchers and companies with widely varying applications, such as organic light emitting diodes, transistors as well as many different sensors. If the circuit should be portable or off-grid, the power sources available are batteries, supercapacitors or some type of power generator. Thermoelectric generators produce electrical energy by the diffusion of charge carriers in response to heat flux caused by a temperature gradient between junctions of dissimilar materials. As wearables, flexible electronics and intelligent packaging applications increase, there is a need for low-cost, recyclable and printable power sources. For such applications, printed thermoelectric generators (TEGs) are an interesting power source, which can also be combined with printable energy storage, such as supercapacitors. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), or PEDOT:PSS, is a conductive polymer that has gathered interest as a thermoelectric material. Plastic substrates are commonly used for printed electronics, but an interesting and emerging alternative is to use paper. In this article, a printed thermoelectric generator consisting of PEDOT:PSS and silver inks was printed on two common types of paper substrates, which could be used to power electronic circuits on paper. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Swedish Knowledge Foundation (KKS

Hybrid 2D Nanomaterials as Dual-mode Contrast Agents in Cellular Imaging

The design of multifunctional nanofluids is highly desirable for biomedical therapy/cellular imaging applications.[1–4] The emergence of hybrid nanomaterials with specific properties, such as magnetism and fluorescence, can lead to an understanding of biological processes at the biomolecular level.[1] Various hybrid systems have been analyzed in the recent past for several possible biomedical applications.[5–9] Carbon-based hybrid systems such as carbon nanotubes with various nanoparticles are being widely tested for their biological applications because of their ability to cross cell membranes and their interesting thermal and electrical properties.[10,11] Graphene oxide (GO) is a fairly new graphene-based system with a 2D carbon honeycomb lattice decorated with numerous functional groups attached to the backbone: these functional groups make it an excellent platform for further attachment of nanoparticles and synthesis of hybrid materials. Cell viability studies on GO have been recently attempted, showing biocompatibility. [12,13] Moreover, the intrinsic photoluminescence (PL) properties of GO can be utilized for cellular imaging.[13] The large surface area and non-covalent interactions with aromatic molecules make GO an excellent system for biomolecular applications and drug attachment

Electrical Sintering of Silver Nanoparticle Ink Studied by In-Situ TEM Probing

Metallic nanoparticle inks are used for printed electronics, but to reach acceptable conductivity the structures need to be sintered, usually using a furnace. Recently, sintering by direct resistive heating has been demonstrated. For a microscopic understanding of this Joule heating sintering method, we studied the entire process in real time inside a transmission electron microscope equipped with a movable electrical probe. We found an onset of Joule heating induced sintering and coalescence of nanoparticles at power levels of 0.1–10 mW/m3. In addition, a carbonization of the organic shells that stabilize the nanoparticles were found, with a conductivity of 4 105 Sm−1

Roadmap on energy harvesting materials

Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere

Porous Gold Films—A Short Review on Recent Progress

Porous gold films have attracted increasing interest over the last ten years due to the unique properties of high specific surface area and electrical conductivity combined with chemical stability and ability to alter the surface chemistry. Several methods have been developed to synthesize porous gold films such as de-alloying, templating, electrochemical, and self-assembling. These porous gold films are used in diverse fields, for example, as electrochemical and Raman sensors or for chemical catalysis. Here, we provide a short review on the progress of porous gold films over the past ten years, including the synthesis and applications of such films

Machine learning-assisted triboelectric nanogenerator-based self-powered sensors

The ability of triboelectric nanogenerators (TENGs) to sense physical, chemical, and physiological activities has been demonstrated. The data generated by TENG sensors encompass various parameters, including time, frequency, intensity, and acceleration. While this information can be used to effectively answer binary queries based on signal intensity, extracting additional intricate details requires an in-depth analysis of the collected TENG sensor data. Often, the amount of data amassed by these sensors surpasses the capability of efficient human analysis, necessitating the assistance of machine learning and deep learning approaches. Typically, supervised machine learning algorithms are employed for data processing, categorization, or identification. This paper provides a comprehensive review of recent advancements in machine learning for TENG sensors and highlights challenges to address in future research.

Porous Gold Films : A Short Review on Recent Progress

Porous gold films have attracted increasing interest over the last ten years due to the unique properties of high specific surface area and electrical conductivity combined with chemical stability and ability to alter the surface chemistry. Several methods have been developed to synthesize porous gold films such as de-alloying, templating, electrochemical, and self-assembling. These porous gold films are used in diverse fields, for example, as electrochemical and Raman sensors or for chemical catalysis. Here, we provide a short review on the progress of porous gold films over the past ten years, including the synthesis and applications of such films