Laser Sweeping Lithography: Parallel Bottom-up Growth Sintering of a Nanoseed–Organometallic Hybrid Suspension for Ecofriendly Mass Production of Electronics

We present a novel laser sweeping lithography (LSL) process, revolving around an ecofriendly mass production method, to fabricate conductive patterns in parallel with no restriction on the type of substrate. Particle-free organometallic solution is reformulated in-process into a nanoseed−organometallic hybrid suspension, via an incomplete thermal decomposition using radiative heating. The growth sintering undergoing a series of ion precipitation, clustering, growing, and agglomeration procedures is then initiated by irradiating a line-modulated diode laser of a near-infrared wavelength through a thermally enforced laser mask on the hybrid suspension. This leads to the concurrent parallel production of silver conductors with a high-conductivity (2.9 μΩ·cm), durability, and resolution of 5 μm on the corresponding to mask openings, without the need of any additional steps and corrosive chemicals. This method is highly effective for large-area fabrication of high-density electronics, as the production time proportionally decreases with increased pattern density and area, compared to conventional laser fabrication methods based on a single laser spot. Therefore, the LSL process is suitable for ecofriendly mass production of various electronic devices in industrial environments

Self-Generated Nanoporous Silver Framework for High-Performance Iron Oxide Pseudocapacitor Anodes

The rapid development of electric vehicles is increasing the demand for next-generation fast-charging energy storage devices with a high capacity and long-term stability. Metal oxide/hydroxide pseudocapacitors are the most promising technology because they show a theoretical capacitance that is 10–100 times higher than that of conventional supercapacitors and rate capability and long-term stability that are much higher than those of Li-ion batteries. However, the poor electrical conductivity of metal oxides/hydroxides is a serious obstacle for achieving the theoretical pseudocapacitor performance. Here, a nanoporous silver (np-Ag) structure with a tunable pore size and ligament is developed using a new silver halide electroreduction process. The structural characteristics of np-Ag (e.g., large specific surface area, electric conductivity, and porosity) are desirable for metal oxide-based pseudocapacitors. This work demonstrates an ultra-high-capacity, fast-charging, and long-term cycling pseudocapacitor anode via the development of an np-Ag framework and deposition of a thin layer of Fe₂O₃ on its surface (np-Ag@Fe₂O₃). The np-Ag@Fe₂O₃ anode shows a capacitance of ∼608 F g^–1 at 10 A g^–1, and ∼84.9% of the capacitance is retained after 6000 charge–discharge cycles. This stable and high-capacity anode, which can be charged within a few tens of seconds, is a promising candidate for next-generation energy storage devices

Simultaneously Enhancing the Cohesion and Electrical Conductivity of PEDOT:PSS Conductive Polymer Films using DMSO Additives

Conductive polymer poly­(3,4-ethylene­dioxy­thiophene):­poly­(styrene­sulfonate) (PEDOT:PSS) has attracted significant attention as a hole transport and electrode layer that substitutes metal electrodes in flexible organic devices. However, its weak cohesion critically limits the reliable integration of PEDOT:PSS in flexible electronics, which highlights the importance of further investigation of the cohesion of PEDOT:PSS. Furthermore, the electrical conductivity of PEDOT:PSS is insufficient for high current-carrying devices such as organic photovoltaics (OPVs) and organic light emitting diodes (OLEDs). In this study, we improve the cohesion and electrical conductivity through adding dimethyl sulfoxide (DMSO), and we demonstrate the significant changes in the properties that are dependent on the wt % of DMSO. In particular, with the addition of 3 wt % DMSO, the maximum enhancements for cohesion and electrical conductivity are observed where the values increase by 470% and 6050%, respectively, due to the inter-PEDOT bridging mechanism. Furthermore, when OLED devices using the PEDOT:PSS films are fabricated using the 3 wt % DMSO, the display exhibits 18% increased current efficiency

Highly Controlled Nanoporous Ag Electrode by Vaporization Control of 2‑Ethoxyethanol for a Flexible Supercapacitor Application

Controlling the surface morphology of the electrode on the nanoscale has been studied extensively because the surface morphology of a material directly leads to the functionalization in various fields of studies. In this study, we designed a simple and cost-effective method to fine-tune the surface morphology and create controlled nanopores on the silver electrode by utilizing 2-ethoxyethanol and two successive heat treatments. High electrical conductivity and mechanical robustness of nanoporous silver corroborate its prospect to be employed in various applications requiring a certain degree of flexibility. As a proof-of-concept, a high-performance supercapacitor was fabricated by electrodepositing MnO₂. This method is expected to be useful in various electronic applications as well as energy storage devices

Transversally Extended Laser Plasmonic Welding for Oxidation-Free Copper Fabrication toward High-Fidelity Optoelectronics

Laser direct processing is a promising approach for future flexible electronics because it enables easy, rapid, scalable, and low-temperature fabrication without using expensive equipment and toxic material. However, its application for nanomaterials with high chemical susceptibility, such as representatively Cu, is limited because severe oxidation occurs under ambient conditions. Here, we report the methodology of a transversally extended laser plasmonic welding process, which outstandingly improves the electrical performance of a Cu conductor (4.6 μΩ·cm) by involving the spatially concurrent laser absorption to the surface oxide-free Cu nanoparticles (NPs). Physical/chemical properties of fabricated Cu conductors are fully analyzed in perspectives of the mechanism based on the thermo-physical-chemical interactions between photon energy and pure Cu NPs. The resultant Cu conductors showed an excellent durability in terms of bending and adhesion. Furthermore, we successfully demonstrated a single layer Cu-mesh-based touch screen panel (TSP) on thermally sensitive polymer film as a breakthrough of typical metal oxide-based transparent touch sensors. The Cu metal mesh exhibited high transmittance (95%) and low sheet resistance (30 Ω/square). This self-capacitance type and multitouchable TSP operated with a fast response, high sensitivity, and durability