Ultrahigh Sensitivity for Thermographic Human-Machine Interface via Precious Metals Atomic Layer Deposition on V-MXene: Computational and Experimental Exploration.

Global healthcare based on the Internet of Things system is rapidly transforming to measure precise physiological body parameters without visiting hospitals at remote patients and associated symptoms monitoring. 2D materials and the prevailing mood of current ever-expanding MXene-based sensing devices motivate to introduce first the novel iridium (Ir) precious metal incorporated vanadium (V)-MXene via industrially favored emerging atomic layer deposition (ALD) techniques. The current work contributes a precise control and delicate balance of Ir single atomic forms or clusters on the V-MXene to constitute a unique precious metal-MXene embedded heterostructure (Ir-ALD@V-MXene) in practical real-time sensing healthcare applications to thermography with human-machine interface for the first time. Ir-ALD@V-MXene delivers an ultrahigh durability and sensing performance of 2.4% °C-1 than pristine V-MXene (0.42% °C-1), outperforming several conventionally used MXenes, graphene, underscoring the importance of the Ir-ALD innovative process. Aberration-corrected advanced ultra-high-resolution transmission/scanning transmission electron microscopy confirms the presence of Ir atomic clusters on well-aligned 2D-layered V-MXene structure and their advanced heterostructure formation (Ir-ALD@V-MXene), enhanced sensing mechanism is investigated using density functional theory (DFT) computations. A rational design empowering the Ir-ALD process on least explored V-MXene can potentially unfold further precious metals ALD-process developments for next-generation wearable personal healthcare devices.

Mo-based MXenes: Synthesis, properties, and applications.

Ti-MXene allows a range of possibilities to tune their compositional stoichiometry due to their electronic and electrochemical properties. Other than conventionally explored Ti-MXene, there have been ample opportunities for the non-Ti-based MXenes, especially the emerging Mo-based MXenes. Mo-MXenes are established to be remarkable with optoelectronic and electrochemical properties, tuned energy, catalysis, and sensing applications. In this timely review, we systematically discuss the various organized synthesis procedures, associated experimental tunning parameters, physiochemical properties, structural evaluation, stability challenges, key findings, and a wide range of applications of emerging Mo-MXene over Ti-MXenes. We also critically examined the precise control of Mo-MXenes to cater to advanced applications by comprehensively evaluating the summary of recent studies using artificial intelligence and machine learning tools. The critical future perspectives, significant challenges, and possible outlooks for successfully developing and using Mo-MXenes for various practical applications are highlighted.

Atomic Layer Deposition-A Versatile Toolbox for Designing/Engineering Electrodes for Advanced Supercapacitors.

Atomic layer deposition (ALD) has become the most widely used thin-film deposition technique in various fields due to its unique advantages, such as self-terminating growth, precise thickness control, and excellent deposition quality. In the energy storage domain, ALD has shown great potential for supercapacitors (SCs) by enabling the construction and surface engineering of novel electrode materials. This review aims to present a comprehensive outlook on the development, achievements, and design of advanced electrodes involving the application of ALD for realizing high-performance SCs to date, as organized in several sections of this paper. Specifically, this review focuses on understanding the influence of ALD parameters on the electrochemical performance and discusses the ALD of nanostructured electrochemically active electrode materials on various templates for SCs. It examines the influence of ALD parameters on electrochemical performance and highlights ALD's role in passivating electrodes and creating 3D nanoarchitectures. The relationship between synthesis procedures and SC properties is analyzed to guide future research in preparing materials for various applications. Finally, it is concluded by suggesting the directions and scope of future research and development to further leverage the unique advantages of ALD for fabricating new materials and harness the unexplored opportunities in the fabrication of advanced-generation SCs.

Self-Formation of a Ru/ZnO Multifunctional Bilayer for the Next-Generation Interconnect Technology via Area-Selective Atomic Layer Deposition.

This study suggests a Ru/ZnO bilayer grown using area-selective atomic layer deposition (AS-ALD) as a multifunctional layer for advanced Cu metallization. As a diffusion barrier and glue layer, ZnO is selectively grown on SiO2 , excluding Cu, where Ru, as a liner and seed layer, is grown on both surfaces. Dodecanethiol (DDT) is used as an inhibitor for the AS-ALD of ZnO using diethylzinc and H2 O at 120 °C. H2 plasma treatment removes the DDT adsorbed on Cu, forming inhibitor-free surfaces. The ALD-Ru film is then successfully deposited at 220 °C using tricarbonyl(trimethylenemethane)ruthenium and O2 . The Cu/bilayer/Si structural and electrical properties are investigated to determine the diffusion barrier performance of the bilayer film. Copper silicide is not formed without the conductivity degradation of the Cu/bilayer/Si structure, even after annealing at 700 °C. The effect of ZnO on the Ru/SiO2 structure interfacial adhesion energy is investigated using a double-cantilever-beam test and is found to increase with ZnO between Ru and SiO2 . Consequently, the Ru/ZnO bilayer can be a multifunctional layer for advanced Cu interconnects. Additionally, the formation of a bottomless barrier by eliminating ZnO on the via bottom, or Cu, is expected to decrease the via resistance for the ever-shrinking Cu lines.

Process Controlled Ruthenium on 2D Engineered V-MXene via Atomic Layer Deposition for Human Healthcare Monitoring.

In searching for unique and unexplored 2D materials, the authors try to investigate for the very first time the use of delaminated V-MXene coupled with precious metal ruthenium (Ru) through atomic layer deposition (ALD) for various contact and noncontact mode of real-time temperature sensing applications at the human-machine interface. The novel delaminated V-MXene (DM-V2 CTx ) engineered ruthenium-ALD (Ru-ALD) temperature sensor demonstrates a competitive sensing performance of 1.11% °C-1 as of only V-MXene of 0.42% °C-1 . A nearly threefold increase in sensing and reversibility performance linked to the highly ordered few-layered V-MXene and selective, well-controlled Ru atomic doping by ALD for the successful formation of Ru@DM-V2 CTX heterostructure. The advanced heterostructure formation, the mechanism, and the role of Ru have been comprehensively investigated by ultra-high-resolution transmission/scanning transmission electron microscopies coupled with next-generation spherical aberration correction technology and fast, accurate elemental mapping quantifications, also by ultraviolet photoelectron spectroscopy. To the knowledge, this work is the first to use the novel, optimally processed V-MXene over conventionally used Ti-MXene and its surface-internal structure engineering by Ru-ALD process-based temperature-sensing devices function and operational demonstrations. The current work could potentially motivate the development of multifunctional, future, next-generation, safe, personal healthcare electronic devices by the industrially scalable ALD technique.

Phosphorus containing layered quadruple hydroxide electrode materials on lab waste recycled flexible current collector.

From environmental waste to energy storage, waste boxes converted into conductive electrodes to further grow active materials has been an interesting way of upcycling. In this study, we transformed waste boxes of KIMTECH Kimwipes® into conductive f-MWCNTs light and flexible substrate (LFS) as current collectors. Then, undoped and P-doped active materials consisting of layered quadruple hydroxides (LQH) was successfully grown on the conductive f-MWCNTs/LFS. Specifically, P-doped f-MWCNTs/LQH demonstrates 1.8 times the capacitance of an undoped f-MWCNTs/LQH. Such conversion of waste boxes not only offers a useful way of reusing waste papers which commonly ends in landfills, but the inexpensive method also offers an extreme way of cutting cost in developing conductive substrates. Also, the effective strategy of synthesizing active materials on the conductive f-MWCNTs/LFS paves its way as potential cheap electrodes of the future generation.

Co-doped In-Situ Engineered Carbon Nano-Onions Enabled High-Performance Supercapacitors.

The feasibility of achieving in situ sulfur (S) and nitrogen (N) co-doped carbon nano-onions (CNOs and SN-CNOs) via a simple flame-pyrolysis technique without using sophisticated high-vacuum annealing or expensive nanodiamond-based complex processes is demonstrated for the first time. The characteristic onion-like feature of 0.34 nm remained intact with a high degree of ordering and graphitization, even though the S and N heteroatoms were co-doped simultaneously. The in situ co-doped SN-CNO demonstrated high supercapacitor device performance with a high energy density of 25 Wh kg-1 at a maximum power density of 18 kW kg-1, maintaining 98% specific capacitance over 10,000 cycles at 10 A g-1. These are the highest achieved device performance values of a fullerene family electrode material to date.

Three-dimensional core-shell heterostructure of tungsten trioxide/bismuth molybdate/cobalt phosphate for enhanced photoelectrochemical water splitting.

Hydrogen has attracted increasing attention as clean energy for fuel cells over the past decade. Photoelectrochemical (PEC) water splitting is considered the most feasible production method but its practical efficiency depends significantly on the photogeneration rate of electron (e-) and hole (h+) on a semiconductor photoanode and the rapid separation of these charge carriers. A proper match of small and large bandgap positions is also necessary. This paper presents a three-dimensional core-shell heterostructured tungsten trioxide/bismuth molybdate/cobalt phosphate (WO3/Bi2MoO6/Co-Pi) photocatalyst synthesized using simultaneous hydrothermal and electrodeposition techniques. Uniform Bi2MoO6 nanoflakes formed on WO3 nanoplates as evidenced by various micro-spectroscopic techniques. The as-prepared WO3/Bi2MoO6/Co-Pi hetero-photocatalyst exhibited significantly high photoelectrochemical activity, where its photocurrent efficiency was 4.6 times greater than that of the constituent WO3. Such drastic improvement in the PEC properties can be corroborated by the appropriate bandgap alignment among WO3, Bi2MoO6, and Co-Pi, resulting in a sufficient charge carrier density with efficient, fast charge-transport complementing their structural-morphological synergy. Furthermore, a heterojunction charge-transfer mechanism was proposed to verify the role of the co-catalyst, Co-Pi, in enhancing the photocurrent at the WO3/Bi2MoO6 photoanode under the same applied bias.

Carbon nano-onion-powered optically transparent and economical dye-sensitized solar cells.

The integration of dye-sensitized solar cells (DSSCs) with building roof panels, windows, and various decorative outdoor installations is presently an important research topic for their immediate commercialization potential because of their power generation capability, sustainability, and aesthetic appearance. For industrial applications, Pt counter electrodes (CEs) need to be replaced with Pt-free CEs because of their limited sources and cost. An ideal CE should be economical, abundant, and have excellent electrochemical stability and activity, with easy processing in bulk. As an alternative practical CE, we introduce for the first time a carbon nano-onion (CNO)-based CE for transparent DSSCs. We developed a simple, energy-efficient one-step synthesis technique for fabricating high-quality CNOs in bulk quantities without any sophisticated instrumentation and expensive nanodiamond precursors. CNO CEs proved to be promising in terms of optical transparency, reasonable electrochemical redox activity for the I-/I3- redox couple, and exchange current density comparable to Pt CEs. CNO-powered DSSCs demonstrated an optical transparency of >55% with a significant solar energy conversion efficiency of 5.17%. The intrinsic hydrophilicity of the as-synthesized CNO eliminates the use of a binder or an additive, unlike in the case of other carbon allotropes. Our results demonstrate the possibility of using CNO-based CEs as promising substitutes for scarce and expensive Pt-based CEs for low-cost DSSCs.

Sulfur Doping: Unique Strategy To Improve the Supercapacitive Performance of Carbon Nano-onions.

Recently, enhancement of the energy density of a supercapacitor is restricted by the inferior capacitance of negative electrodes, which impedes the commercial development of high-performance symmetric and asymmetric supercapacitors. This article introduces the in situ bulk-quantity synthesis of hydrophilic, porous, graphitic sulfur-doped carbon nano-onions (S-CNO) using a facile flame-pyrolysis technique and evaluated its potential applications as a high-performance supercapacitor electrode in a symmetric device configuration. The high-surface wettability in the as-prepared state enables the formation of highly suspended active conducting material S-CNO ink, which eliminates the routine use of binders for the electrode preparation. The as-prepared S-CNO displayed encouraging features for electrochemical energy storage applications with a high specific surface area (950 m2 g-1), ordered mesoporous structure (∼3.9 nm), high S-content (∼3.6 at. %), and substantial electronic conductivity, as indicated by the ∼80% sp2 graphitic carbon content. The in situ sulfur incorporation into the carbon framework of the CNO resulted in a high-polarized surface with well-distributed reversible pseudosites, increasing the electrode-electrolyte interaction and improving the overall conductivity. The S-CNOs showed a specific capacitance of 305 F g-1, an energy density of 10.6 W h kg-1, and a power density of 1004 W kg-1 at an applied current density of 2 A g-1 in a symmetrical two-electrode cell configuration, which is approximately three times higher than that of the pristine CNO-based device in a similar electrochemical testing environment. Even at 11 A g-1, the S-CNO||S-CNO device rendered an energy density (6.1 W h kg-1) at a deliverable power density of 5.5 kW kg-1, indicating a very good rate capability and power management during peak power delivery applications. Furthermore, it showed a high degree of electrochemical reversibility with excellent cycling stability, retaining ∼95% of its initial capacitance after more than 10 000 repetitive charge-discharge cycles at an applied current density of 5 A g-1.