Flashlight-induced Ultrafast, Scalable Surface Activation of Highly Loaded Graphite Composite Anode.

Herein, a straightforward route for fabricating highly loaded graphite composite anodes with enhanced electrochemical performance via ultrafast, scalable flashlight irradiation is presented. When a flashlight irradiates the surface of a thick graphite anode, instantaneous and non-equilibrium photo-thermochemical interactions occur between the flashlight and the constituent materials of the anode. As a result, a porous structure (through which the electrolyte easily penetrates), a large reaction site, improved conductivity, as well as phase transformation of active graphite material can be developed on the anode surface, which can facilitate ion and electron transport at the interface with the electrolyte.

Scalable Multistep Roll-to-Roll Printing of Multifunctional and Robust Reentrant Microcavity Surfaces via a Wetting-Induced Process.

Owing to their unique structural robustness, interconnected reentrant structures offer multifunctionality for various applications. a scalable multistep roll-to-roll printing method is proposed for fabricating reentrant microcavity surfaces, coined as wetting-induced interconnected reentrant geometry (WING) process. The key to the proposed WING process is a highly reproducible reentrant structure formation controlled by the capillary action during contact between prefabricated microcavity structure and spray-coated ultraviolet-curable resins.

Impedance spectroscopy of SbSe photovoltaics consisting of (SbSe) nanoribbons under light illumination.

SbSe, consisting of one-dimensional (SbSe) nanoribbons has drawn attention as an intriguing light absorber from the photovoltaics (PVs) research community. However, further research is required on the performance-limiting factors in SbSe PVs. In this study, we investigated the charge carrier behavior in SbSe PVs by impedance spectroscopy (IS) under light illumination.

Fabrication of Highly Sensitive Capacitive Pressure Sensors Using a Bubble-Popping PDMS.

Attempts have been made to introduce microstructures or wrinkles into the elastomer surface to increase the sensitivity of the elastomer. However, the disadvantage of this method is that when a force is applied to the pressure sensor, the contact area with the electrode is changed and the linear response characteristic of the pressure sensor is reduced. The biggest advantage of the capacitive pressure sensor using an elastomer is that it is a characteristic that changes linearly according to the change in pressure, so it is not suitable to introduce microstructures or wrinkles into the elastomer surface.

Flash-Induced High-Throughput Porous Graphene via Synergistic Photo-Effects for Electromagnetic Interference Shielding.

Porous 2D materials with high conductivity and large surface area have been proposed for potential electromagnetic interference (EMI) shielding materials in future mobility and wearable applications to prevent signal noise, transmission inaccuracy, system malfunction, and health hazards. Here, we report on the synthesis of lightweight and flexible flash-induced porous graphene (FPG) with excellent EMI shielding performance. The broad spectrum of pulsed flashlight induces photo-chemical and photo-thermal reactions in polyimide films, forming 5 × 10 cm-size porous graphene with a hollow pillar structure in a few milliseconds.

Intense Pulsed Light Thermal Treatment of Pb(Zr,Ti)O /Metglas Heterostructured Films Resulting in Extreme Magnetoelectric Coupling of over 20 V cm Oe.

Magnetoelectric (ME) film composites consisting of piezoelectric and magnetostrictive materials are promising candidates for application in magnetic field sensors, energy harvesters, and ME antennas. Conventionally, high-temperature annealing is required to crystallize piezoelectric films, restricting the use of heat-sensitive magnetostrictive substrates that enhance ME coupling. Herein, a synergetic approach is demonstrated for fabricating ME film composites that combines aerosol deposition and instantaneous thermal treatment based on intense pulsed light (IPL) radiation to form piezoelectric Pb(Zr,Ti)O (PZT) thick films on an amorphous Metglas substrate.

A 2D Ultrathin Nanopatterned Interlayer to Suppress Lithium Dendrite Growth in High-Energy Lithium-Metal Anodes.

A novel strategy for robust and ultrathin (<1 µm) multilayered protective structures to address uncontrolled Lithium (Li) dendrite growth at Li-metal battery anodes is reported. Synergetic interaction among Ag nanoparticles (Ag NPs), reduced graphene oxide (rGO) films, and self-assembled block-copolymer (BCP) layers enables effective suppression of dendritic Li growth. While Ag NP layer confines the growth of Li metal underneath the rGO layer, BCP layer facilitates the fast and uniformly distributed flux of Li-ion transport and mechanically supports the rGO layer.

A Hierarchical Metal Nanowire Network Structure for Durable, Cost-Effective, Stretchable, and Breathable Electronics.

Polymer nanofiber-based porous structures ("breathable devices") have been developed for breathable epidermal electrodes, piezoelectric nanogenerators, temperature sensors, and strain sensors, but their applications are limited because increasing the porosity reduces device robustness. Herein, we report an approach to produce ultradurable, cost-effective breathable electronics using a hierarchical metal nanowire network and an optimized photonic sintering process. Photonic sintering significantly reduces the sheet resistance (16.

Strategically Controlled Flash Irradiation on Silicon Anode for Enhancing Cycling Stability and Rate Capability toward High-Performance Lithium-Ion Batteries.

Si has attracted considerable interest as a promising anode material for next-generation Li-ion batteries owing to its outstanding specific capacity. However, the commercialization of Si anodes has been consistently limited by severe instabilities originating from their significant volume change (approximately 300%) during the charge-discharge process. Herein, we introduce an ultrafast processing strategy of controlled multi-pulse flash irradiation for stabilizing the Si anode by modifying its physical properties in a spatially stratified manner.

Control of thermal deformation with photonic sintering of ultrathin nanowire transparent electrodes.

Development of electronic devices on ultrathin flexible plastic substrates is of great value in terms of portability, cost reduction, and mechanical flexibility. However, because thin plastic substrates with low heat capacity can be more easily damaged by thermal energy, their use is limited. Highly flexible nanowire (NW) transparent conductive electrodes on ultrathin (∼10 μm) low cost polyethylene terephthalate (PET) substrates are fabricated.

High-Resolution and Large-Area Patterning of Highly Conductive Silver Nanowire Electrodes by Reverse Offset Printing and Intense Pulsed Light Irradiation.

Conventional printing technologies such as inkjet, screen, and gravure printing have been used to fabricate patterns of silver nanowire (AgNW) transparent conducting electrodes (TCEs) for a variety of electronic devices. However, they have critical limitations in achieving micrometer-scale fine line width, uniform thickness, sharp line edge, and pattering of various shapes. Moreover, the optical and electrical properties of printed AgNW patterns do not satisfy the performance required by flexible integrated electronic devices.

Three-Dimensionally Printed Stretchable Conductors from Surfactant-Mediated Composite Pastes.

A stretchable conductor is a critical prerequisite to achieve various forms of stretchable electronics. In particular, directly printable stretchable conductors have gathered considerable attention with recent growing interest in a variety of large-area, deformable electronics. In this study, we have developed a chemical pathway of incorporating a surfactant with a moderate hydrophilic-lipophilic balance in formulating composite pastes for printed stretchable conductors, with a possibility of a vertically stackable, three-dimensional printing process.

Defect-Free, Highly Uniform Washable Transparent Electrodes Induced by Selective Light Irradiation.

A simple route to fabricate defect-free Ag-nanoparticle-carbon-nanotube composite-based high-resolution mesh flexible transparent conducting electrodes (FTCEs) is explored. In the selective photonic sintering-based patterning process, a highly soft rubber or thin plastic substrate is utilized to achieve close and uniform contact between the composite layer and photomask, with which uniform light irradiation can be obtained with diminished light diffraction. This well-controlled process results in developing a fine and uniform mesh pattern (≈12 μm).

A photonic sintering derived Ag flake/nanoparticle-based highly sensitive stretchable strain sensor for human motion monitoring.

Recently, the demand for stretchable strain sensors used for detecting human motion is rapidly increasing. This paper proposes high-performance strain sensors based on Ag flake/Ag nanocrystal (NC) hybrid materials incorporated into a polydimethylsiloxane (PDMS) elastomer. The addition of Ag NCs into an Ag flake network enhances the electrical conductivity and sensitivity of the strain sensors.

Enhanced Oxidation-Resistant Cu@Ni Core-Shell Nanoparticles for Printed Flexible Electrodes.

In this work, the fabrication and application of highly conductive, robust, flexible, and oxidation-resistant Cu-Ni core-shell nanoparticle (NP)-based electrodes have been reported. Cu@Ni core-shell NPs with a tunable Ni shell thickness were synthesized by varying the Cu/Ni molar ratios in the precursor solution. Through continuous spray coating and flash photonic sintering without an inert atmosphere, large-area Cu@Ni NP-based conductors were fabricated on various polymer substrates.

Selective Light-Induced Patterning of Carbon Nanotube/Silver Nanoparticle Composite To Produce Extremely Flexible Conductive Electrodes.

Recently, highly flexible conductive features have been widely demanded for the development of various electronic applications, such as foldable displays, deformable lighting, disposable sensors, and flexible batteries. Herein, we report for the first time a selective photonic sintering-derived, highly reliable patterning approach for creating extremely flexible carbon nanotube (CNT)/silver nanoparticle (Ag NP) composite electrodes that can tolerate severe bending (20 000 cycles at a bending radius of 1 mm). The incorporation of CNTs into a Ag NP film can enhance not only the mechanical stability of electrodes but also the photonic-sintering efficiency when the composite is irradiated by intense pulsed light (IPL).

Continuous Patterning of Copper Nanowire-Based Transparent Conducting Electrodes for Use in Flexible Electronic Applications.

Simple, low-cost and scalable patterning methods for Cu nanowire (NW)-based flexible transparent conducting electrodes (FTCEs) are essential for the widespread use of Cu NW FTCEs in numerous flexible optoelectronic devices, wearable devices, and electronic skins. In this paper, continuous patterning for Cu NW FTCEs via a combination of selective intense pulsed light (IPL) and roll-to-roll (R2R) wiping process was explored. The development of continuous R2R patterning could be achieved because there was significant difference in adhesion properties between NWs and substrates depending on whether Cu NW coated area was irradiated by IPL or not.

Roll-to-roll-compatible, flexible, transparent electrodes based on self-nanoembedded Cu nanowires using intense pulsed light irradiation.

Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control.

Promising wet chemical strategies to synthesize Cu nanowires for emerging electronic applications.

Copper nanowires (Cu NWs) are of particular interest for application as transparent and flexible conducting electrodes in 'see-through' and/or 'deformable' future electronics due to their excellent electrical, optical, and mechanical properties. It is necessary to develop reliable and facile methods to produce well-defined Cu NWs prior to their full exploitation. Among the wide variety of methods available to generate Cu NWs, solution-based synthesis routes are considered to be a promising strategy because of several advantages including fewer constraints on the selection of precursors, the solvent and reaction conditions, and the feasibility of large-scale low-cost production.

Aqueous Solution-Phase Selenized CuIn(S,Se)2 Thin Film Solar Cells Annealed under Inert Atmosphere.

A nonvacuum solution-based approach can potentially be used to realize low cost, roll-to-roll fabrication of chalcopyrite CuIn(S,Se)2 (CISSe) thin film solar cells. However, most solution-based fabrication methods involve highly toxic solvents and inevitably require sulfurization and/or postselenization with hazardous H2S/H2Se gases. Herein, we introduce novel aqueous-based Cu-In-S and Se inks that contain an amine additive for producing a high-quality absorber layer.

Role of anions in aqueous sol-gel process enabling flexible Cu(In,Ga)S2 thin-film solar cells.

Recently, environmental-friendly, solution-processed, flexible Cu(In,Ga)(S,Se)2 devices have gained significant interest, primarily because the solution deposition method enables large-scale and low-cost production of photovoltaics, and a flexible substrate can be implemented on uneven surfaces in various applications. Here, we suggest a novel green-chemistry aqueous ink that is readily achievable through the incorporation of molecular precursors in an aqueous medium. A copper formate precursor was introduced to lower the fabrication temperature, provide compatibility with a polyimide plastic substrate, and allow for high photovoltaic performance.

Band-gap-graded Cu2ZnSn(S1-x,Se(x))4 solar cells fabricated by an ethanol-based, particulate precursor ink route.

Solution processing of earth-abundant Cu2ZnSn(S1-x,Sex)4 (CZTSSe) absorber materials is an attractive research area in the economical and large-scale deployment of photovoltaics. Here, a band-gap-graded CZTSSe thin-film solar cell with 7.1% efficiency was developed using non-toxic solvent-based ink without the involvement of complex particle synthesis, highly toxic solvents, or organic additives.

Highly concentrated synthesis of copper-zinc-tin-sulfide nanocrystals with easily decomposable capping molecules for printed photovoltaic applications.

Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles.