Stretchable and Skin-Conformal Thermoelectric Generator with Highly Flexible and Plastically Bendable Silver Selenide Films.

Among inorganic thermoelectric materials, flexible thermoelectric materials have attracted considerable attention. In this study, highly flexible and plastically bendable silver selenide films with excellent thermoelectric performance at room temperature are presented. The flexibility of the freestanding silver selenide films was significantly improved through a simple annealing treatment.

Accelerometer-derived physical activity and sedentary behavior patterns among Korean adults.

Purpose: This study aimed to provide an overview of accelerometer-derived physical activity (PA) and sedentary behavior (SB) patterns among Korean adults. We also investigated the association between participant characteristics and the likelihood of adherence to moderate-to-vigorous physical activity (MVPA), SB, and the MVPA-SB guidelines.

Methods: Data from the 2014-2017 Korea National Health and Nutrition Examination Survey were used.

Effectiveness of a Mobile Wellness Program for Nurses with Rotating Shifts during COVID-19 Pandemic: A Pilot Cluster-Randomized Trial.

Nurses with rotating shifts, including night shifts, have suffered from low physical activity during the COVID-19 pandemic and lower sleep quality due to the disruption of their circadian rhythm. This study aimed to develop and examine the effectiveness of a mobile wellness program on daily steps, sleep quality, exercise self-efficacy, intrinsic motivation for exercise, self-rated fatigue, and wellness. A cluster randomized controlled trial design was used to examine the effectiveness of the mobile wellness program for nurses with rotating shifts.

Highly Flexible and Durable Thermoelectric Power Generator Using CNT/PDMS Foam by Rapid Solvent Evaporation.

Using a simple, rapid solvent evaporation process, the authors produced 3D carbon nanotube (CNT)/polydimethylsiloxane (PDMS) foams with both high thermoelectric (TE) and good mechanical performance and used them to fabricate highly flexible and durable TE generators. The numerous pores and interfaces in the CNT/PDMS foams, which have porosities exceeding 87%, afford very low thermal conductivity of 0.13 W m K .

Microstructure and Thermoelectric Characterization of Composite Nanofiber Webs Derived from Polyacrylonitrile and Sodium Cobalt Oxide Precursors.

We report the microstructure and thermoelectric properties of composite nanofiber webs, which were fabricated by dual-electrospinning of polyacrylonitrile (PAN) and sodium cobalt oxide (NaCoO) precursor solutions with different input compositions and following heat-treatment at 600-900 °C for simultaneous carbonation and calcination. The SEM and EDS mapping images revealed that PAN-derived carbon nanofibers (CNFs) and NaCoO-based ceramic nanofibers coexisted in the composite nanofiber webs and that their relative contents could be controlled by the input compositions. The Seebeck coefficient increased from ~26.

Proton Conducting Perhydropolysilazane-Derived Gate Dielectric for Solution-Processed Metal Oxide-Based Thin-Film Transistors.

Perhydropolysilazane (PHPS), an inorganic polymer composed of Si-N and Si-H, has attracted much attention as a precursor for gate dielectrics of thin-film transistors (TFTs) due to its facile processing even at a relatively low temperature. However, an in-depth understanding of the tunable dielectric behavior of PHPS-derived dielectrics and their effects on TFT device performance is still lacking. In this study, the PHPS-derived dielectric films formed at different annealing temperatures have been used as the gate dielectric layer for solution-processed indium zinc oxide (IZO) TFTs.

Thermoelectric fibers from well-dispersed carbon nanotube/poly(vinyliedene fluoride) pastes for fiber-based thermoelectric generators.

High-performance thermoelectric composite fibers were prepared via simple wet-spinning of single-walled carbon nanotube (SWCNT)/poly(vinylidene fluoride) (PVDF) pastes using a common solvent/coagulation system. By improving the content and dispersion state of SWCNTs in the composite fibers, the thermoelectric performance could be effectively enhanced. With n-type doping of SWCNTs using polyethylenimine, high-performance n-type SWCNT/PVDF composite fibers could be prepared.

High Thermoelectric Power Factor of a Diketopyrrolopyrrole-Based Low Bandgap Polymer via Finely Tuned Doping Engineering.

We studied the thermoelectric properties of a diketopyrrolopyrrole-based semiconductor (PDPP3T) via a precisely tuned doping process using Iron (III) chloride. In particular, the doping states of PDPP3T film were linearly controlled depending on the dopant concentration. The outstanding Seebeck coefficient of PDPP3T assisted the excellent power factors (PFs) over 200 μW mK at the broad range of doping concentration (3-8 mM) and the maximum PF reached up to 276 μW mK, which is much higher than that of poly(3-hexylthiophene), 56 μW mK.

Foldable Thermoelectric Materials: Improvement of the Thermoelectric Performance of Directly Spun CNT Webs by Individual Control of Electrical and Thermal Conductivity.

We suggest the fabrication of foldable thermoelectric (TE) materials by embedding conducting polymers into Au-doped CNT webs. The CNT bundles, which are interconnected by a direct spinning method to form 3D networks without interfacial contact resistance, provide both high electrical conductivity and high carrier mobility. The ZT value of the spun CNT web is significantly enhanced through two simple processes.

Facile Preparation of Highly Conductive Metal Oxides by Self-Combustion for Solution-Processed Thermoelectric Generators.

Highly conductive indium zinc oxide (IZO) thin films were successfully fabricated via a self-combustion reaction for application in solution-processed thermoelectric devices. Self-combustion efficiently facilitates the conversion of soluble precursors into metal oxides by lowering the required annealing temperature of oxide films, which leads to considerable enhancement of the electrical conductivity of IZO thin films. Such enhanced electrical conductivity induced by exothermic heat from a combustion reaction consequently yields high performance IZO thermoelectric films.

Solution synthesis of telluride-based nano-barbell structures coated with PEDOT:PSS for spray-printed thermoelectric generators.

Unlabelled: Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded

Pedot: PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators.

Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment.

Unlabelled: The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (

Pedot: PSS) and tellurium-

Pedot: PSS (Te-

Pedot: PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of

Pedot: PSS and Te-

Pedot: PSS hybrid composites from 787.

Enhanced thermoelectric performance of bar-coated SWCNT/P3HT thin films.

The influence of processing conditions, such as ink concentration and coating method, on the thermoelectric properties of SWCNT/P3HT nanocomposite films was investigated systematically. Using simple wire-bar-coating, SWCNT/P3HT nanocomposite films with high thermoelectric performance could be obtained without additional P3HT doping. The wire-bar-coated SWCNT/P3HT nanocomposite films exhibited power factors of up to 105 μW m(-1) K(-2) at room temperature.

Ambient atmosphere-processable, printable Cu electrodes for flexible device applications: structural welding on a millisecond timescale of surface oxide-free Cu nanoparticles.

Recently, various functional devices based on printing technologies have been of paramount interest, owing to their characteristic processing advantages along with excellent device performance. In particular, printable metallic electrodes have drawn attention in a variety of optoelectronic applications; however, research into printable metallic nanoparticles has been limited mainly to the case of an environmentally stable Ag phase. Despite its earth-abundance and highly conductive nature, the Cu phase, to date, has not been exploited as an ambient atmosphere-processable, printable material due to its critical oxidation problem in air.

Resist-free antireflective nanostructured film fabricated by thermal-NIL.

Resist-free antireflective (AR) nanostructured films are directly fabricated on polycarbonate (PC) film using thermal-nanoimprint lithography (T-NIL) and the moth-eye shape of AR nanostructure is elaborately optimized with different oxygen reactive ion etching conditions. Anodic aluminum oxide (AAO) templates are directly used as master molds of T-NIL for preparation of AR nanostructures on PC film without an additional T-NIL resist. AR nanostructures are well arranged with a period of about 200 nm and diameter of about 150 nm, which corresponds to those of the AAO template mold.