Indium Tin Oxide Research Articles

Dual Redox‐active Covalent Organic Framework‐based Memristors for Highly‐efficient Neuromorphic Computing

Organic memristors based on covalent organic frameworks (COFs) exhibit significant potential for future neuromorphic computing applications. The preparation of high‐quality COF nanosheets through appropriate structural design and building block selection is critical for the enhancement of memristor performance. In this study, a novel room‐temperature single‐phase method was used to synthesize Ta‐Cu3 COF, which contains two redox‐active units: trinuclear copper and triphenylamine. The resultant COF nanosheets were dispersed through acid‐assisted exfoliation and subsequently spin‐coated to fabricate a high‐quality COF film on an indium tin oxide (ITO) substrate. The synergistic effect of the dual redox‐active centers in the COF film, combined with its distinct crystallinity, significantly reduces the redox energy barrier, enabling the efficient modulation of 128 non‐volatile conductive states in the Al/Ta‐Cu3 COF/ITO memristor. Utilizing a convolutional neural network (CNN) based on these 128 conductance states, image recognition for ten representative campus landmarks was successfully executed, achieving a high recognition accuracy of 95.13% after 25 training epochs. Compared to devices based on binary conductance states, the memristor with 128 conductance states exhibits a 45.56% improvement in recognition accuracy and significantly enhances the efficiency of neuromorphic computing.

Inverse-designed multi-diameter InAs nanowire array ultra-broadband photodetectors enhanced by localized surface plasmon resonances

Multi-diameter InAs nanowire array ultra-broadband photodetectors are inversely designed and further enhanced by localized surface plasmon resonances. The nanowire diameters are carefully selected by the particle swarm optimization algorithm within the range of 100-800 nm. The multi-diameter nanowire array exhibits high absorption over 80% within a broadband wavelength range of 0.5-3.42 µm, much wider and flatter than that of the single-diameter counterpart, which is attibuted to the superposition of multiple absorption peaks as well as the extension of absorption to longer wavelengths. By introducing indium tin oxide nanoparticles onto the nanowire surface, the lowest absorption is further raised to 87% within a broad wavelength range of 0.55-3.5 µm due to the localized surface plasmon resonances, and the dark current density is substantially reduced from 214 mA/cm2 to 83 mA/cm2 due to the large depletion region. This work may pave the way for the development of ultra-broadband high-responsivity infrared photodetectors.

Investigation of a microfluidic free-flow electrophoresis chip of glass substrate with integrated indium tin oxide electrodes

Free-flow electrophoresis (FFE) is a unique form of electrophoresis that allows continuous electrophoresis separation. Small scale FFE is very practical for processing of limited amounts of samples for analytical purposes. In this work, glass substrate was designed as a chip FFE and its performance was visually demonstrated and characterized using fluorescent probes. The chip consisted of two pieces of glass substrate. One of them was patterned with a planar indium tin oxide (ITO) electrodes, and the other glass was designed with inlets for sample infusion and electrolyte transfer. The depth of the separation channel (15 × 60 mm) is defined by a tape spacer of 85 μm. Since the integrated ITO electrodes in direct contact with the working solution in the separation channel, a voltage as high as 600 V can be applied without bubbling problems. The main operation factors such as buffer concentration, pH, voltage, and flow rate were optimized to separate the probes, and the results were compared with capillary electrophoresis. The role of EOF and electrolysis was also discussed. Compared to photolithographic wet etching, this design is easier to implement, and it enables effective FFE operation. This chip FFE system has potential application in processing and cell sorting.

Three-wave mixing experiments in indium–tin–oxide thin-films with no phase matching

Abstract One challenge of using nonlinear optical phenomena for practical applications is the need to perform phase-matching. Recently, epsilon-near-zero materials have been shown to demonstrate strong optical nonlinearities, in addition to their other unique properties. As suggested by their name, the permittivity of the material is close to zero for a certain wavelength range. We demonstrate that this small permittivity allows for efficient three-wave mixing interactions to take place in indium–tin–oxide thin films without the need for phase matching the pump and signal beams. The efficiency of the second-order nonlinear interactions is characterized, and cascaded three-wave mixing is demonstrated.

N-doped MoS2@indium tin oxide (ITO) core–shell nanowires for high-performance ammonium ion micro-supercapacitor

Ammonium (NH4+) ion aqueous supercapacitors have gained significant attention due to their notable cost-effectiveness, safety profile, and environmental benefits. Despite this, the optimization of the capacitive performance of electrode materials for NH4+ ion storage remains inadequate. To tackle these challenges, we present a composite electrode depend upon molybdenum disulfide (MoS2) and indium tin oxide nanowires (MoS2@ITO NWs) as the primary host for (NH4+) ions. Additionally, we introduce a straightforward radio frequency nitrogen (N) plasma technique to incorporate nitrogen doping into the MoS2 film, thereby enhancing its performance. The introduction of N plasma doping into two-dimensional MoS2 results in an expansion of the interlayer distance and an improvement in electronic conductivity. This, in turn, facilitates the facile and highly reversible insertion and extraction of NH4+ ions during cycling. Consequently, the N plasma doping significantly enhances the device areal capacitance of MoS2@ITO NWs, increasing it from 78.6 to 161.8 mF cm−2 at 1 mA cm−2, with an exceptional capacity retention (>89.2% after 10 000 cycles) and superior rate capability up to 10 mA cm−2. The integration N of atoms within the straightforward hierarchical core–shell design strategy exhibits promising prospects for bolstering the performance of metal sulfide electrodes and other high-capacity electrode materials aimed at energy storage applications.

Transition metals-based electrocatalysts on super-flat substrate for perovskite photovoltaic hydrogen production with 13.75% solar to hydrogen efficiency

Harnessing the inexhaustible solar energy for water splitting is regarded one of the most promising strategies for hydrogen production. However, sluggish kinetics of oxygen evolution reaction (OER) and expensive photovoltaics have hindered commercial viability. Here, an adhesive-free electrodeposition process is developed for in-situ preparation of earth-abundant electrocatalysts on super-flat indium tin oxide (ITO) substrate. NiFe hydroxide exhibited prominent OER performance, achieving an ultra-low overpotential of 236 mV at 10 mA/cm2 in alkaline solution. With the superior OER activity, we achieved an unassisted solar water splitting by series connected perovskite solar cells (PSCs) of 2 cm2 aperture area with NiFe/ITO//Pt electrodes, yielding overall solar to hydrogen (STH) efficiency of 13.75 %. Furthermore, we upscaled the monolithic facility to utilize perovskite solar module for large-scale hydrogen production and maintained an approximate operating current of 20 mA. This creative strategy contributes to the decrease of industrial manufacturing expenses for perovskite-based photovoltaic-electrochemical (PV-EC) hydrogen production, further accelerating the conversion and utilization of carbon-free energy.

Enhanced selective extraction of indium and gallium using mesoporous sorbents

Gallium (Ga) and indium (In) are essential elements in numerous industries, most notably in the rapidly evolving field of optical electronics. Due to their scarcity in natural resources coupled with escalating demand, there is an urgent need to develop sustainable technologies for extracting these elements from secondary sources. This study presents the innovative application of two highly efficient sorbents, namely mesoporous silica (SBA-15) and ligand-modified mesoporous silica, for the selective extraction of critical elements like indium and gallium from various multi-element solutions. The SBA-15 sorbent showcased remarkable efficiency in adsorbing gallium at a pH of 3, achieving an excellent adsorption capacity of approximately 90 mg/g, which surpasses previously reported values. Conversely, the ligand-modified silica demonstrated significant effectiveness in extracting indium, with an adsorption capacity of ∼ 32 mg/g at pH 3. Furthermore, SBA-15 exhibited remarkable selectivity for gallium in solutions containing Ga, In, and Zn, thereby significantly enhancing the possible recovery of Ga from In/Ga/ZnO semiconductor targets. Additionally, the sorbent displayed exceptional separation efficiency between Ga and Al as well as Ga and In. Similarly, ligand-modified silica showed high selectivity for indium in solutions containing Ga, In, and Zn, achieving excellent separation between In and Zn. Moreover, it effectively extracted indium in binary solutions of In and Sn ions, thereby advancing the recovery of indium from ITO (indium tin oxide) films. After ten cycles of reuse, the sorbents maintained their adsorption capacities, underscoring their potential for industrial applications.

Development of Portable Multi-fluorescence Detection System Using Indium Tin Oxide Heater for Loop-mediated Isothermal Amplification

Development of Portable Multi-fluorescence Detection System Using Indium Tin Oxide Heater for Loop-mediated Isothermal Amplification

Early detection of the ovarian cancer with a label-free and disposable ITO-PET based immunosensor platform

Alpha fetoprotein (AFP), a popular biomarker for ovarian cancer, was the target of this studyto create an immunosensor based on electrochemical impedance spectroscopy (EIS). For this purpose, a disposable Indium tin oxide coated PET (In2O3/SnO2, ITO-PET) electrode was used as a basic electrode for working of the triple electrode system and the electrodes were modified with 3-(Trimethoxy silyl) propyl methacrylate (3- TMSPM) silanization agent. Although there are studies on the determination of AFP, the determination of AFP with a cheap, flexible and sensitive electrode system such as ITO-PET in this study makes the study remarkable. With the designed biosensors, AFP protein determination at a wide concentration range (0.05 pg/mL-100 pg/mL) could be successfully performed. To prove that the designed immunosensor was constructed correctly, linear range, repeatability, reproducibility and regeneration capacity (characterization studies) were investigated. Obtaining successful results in the storage capacity studies of the biosensor, which has high reproducibility and repeatability, showed that it also has potential for commercial use. The high specificity of the biosensor also proves its reliability. Finally, the performance of the biosensor in commercial human serum samples was also evaluated.

Highly sensitive and stretchable fiber strain sensors based on ITO NPs/CNTs composite

Flexible and multifunctional sensors are in demand in various fields, but achieving excellent sensitivity and an extensive operational range poses a challenge. Here, we developed a flexible strain sensor using a cost-effective dip-coating method, incorporating microcracked synergistic indium tin oxide nanoparticles (ITO NPs) and carbon nanotubes (CNTs) in a conductive layer. Utilizing an elastic rubber core string as the stretchable substrate and Thermoplastic polyurethane (TPU) as an interfacial modifier, we established connectivity between the substrate and conductive layer. After encapsulation with polydimethylsiloxane, the ITO NPs/CNTs/rubber fiber (ICRF) strain sensor was fabricated. This sensor demonstrates a broad sensing range (0 ∼ 300 %), remarkable sensitivity (GF=1033.57), swift response/recovery times (174.55 ms/180.27 ms), and exceptional durability and stability (>2000 cycles). Moreover, it proves effective for human motion detection, underscoring its potential in flexible and wearable devices. Finally, precise responses of the mechanical claw’s posture and grasping demonstrate its potential applications across multiple fields.

Two-phase/two-gap scenario in heavily reduced superconducting ITO films revealed by point-contact spectroscopy

We present the first point-contact measurements of heavily reduced indium tin oxide (ITO) films in the superconducting state, which simultaneously demonstrate high transparency in the visible light spectrum. Analysis of the differential conductance spectrum indicates the presence of two superconducting phases, the main one with a critical temperature Tc of about 4.6 K and an additional phase with Tc ∼ 10 K, most likely localized near the surface. The phase separation is indirectly confirmed by resistance measurements of the layers and ab initio calculations of the doped ITO electronic structure. The results obtained give hope for the creation of transparent superconducting films with critical temperatures of about 10 K.

Electric tuning of plasmonic resonances in ultrathin gold nanoribbon arrays

Ultrathin plasmonic nanostructures offer an unparalleled opportunity for the study of light–matter interactions at the nanoscale and realization of compact nanophotonic devices. In this study, we introduce an ultrathin gold nanoribbon array and demonstrate an electric approach to actively tuning its plasmonic resonance, which leveraging the extreme light confinement capability in the ultrathin plasmonic nanostructure and a robust nanoscale electro-optical effect in indium tin oxide. Optimizing the design (to a total thickness as small as 12 nm for a 2-nm-thick gold nanoribbon array), we numerically demonstrate a spectral shift in the plasmonic resonance up to 36 nm along with an approximately 16% change in the transmission at a gate voltage below 1.7 V at the wavelength of 1.47 μm. This work presents progress towards electric tuning of plasmonic resonances in ultrathin metallic nanostructures for various applications including surface-enhanced spectroscopy, spontaneous emission enhancement, and optical modulation.

Flexible Nanoscale Amorphous Oxide Transistors with a Gold-Assisted Transfer Method.

We present a new approach to achieve nanoscale transistors on ultrathin flexible substrates with conventional electron-beam lithography. Full devices are first fabricated on a gold sacrificial layer covering a rigid silicon substrate, and then coated with a polyimide film and released from the rigid substrate. This approach bypasses nanofabrication constraints on flexible substrates: (i) electron-beam surface charging, (ii) alignment inaccuracy due to the wavy substrate, and (iii) restricted thermal budgets. As a proof-of-concept, we demonstrate ∼100 nm long indium tin oxide (ITO) transistors on ∼6 μm thin polyimide. This is achieved with sub-20 nm misalignment or overlap between source (or drain) and gate contacts on flexible substrates for the first time. The estimated transit frequency of our well-aligned devices can be up to 3.3 GHz, which can be further improved by optimizing the device structure and performance.

Milk Tea–Colored Perovskite Solar Cells Fabricated Through a Multilayer Film Design

This study presents the fabrication of perovskite thin-film solar cells (PTSCs) with adjustable colors, achieved through a multilayer film design. The multilayer film, comprising Au and indium-tin-oxide (ITO), functions as an adjusted color reflectance (ACR) multilayer film. When the ITO thickness is varied from 100 to 150 nm, the color of the PTSCs can be adjusted from lighter shades that resemble fresh milk tea to darker tones akin to caramel. The color changes that the ACR multilayer film induces correlate well with its reflectance response. Compared with traditional black-colored PTSCs, the milk tea–colored PTSCs maintain a power conversion efficiency of >12%. This achievement suggests the potential for fabricating PTSCs in various colors and patterns that are suitable for use in furnishings, accessories, and other applications.

Efficient and Stable Monolithic Perovskite/Silicon Tandem Solar Cells Enabled by Contact-Resistance-Tunable Indium Tin Oxide Interlayer.

The imperfect charge behavior at the interfaces of perovskite/electron-transport layer (ETL)/transparent conducting oxide (TCO) limits the further performance improvement of perovskite/silicon tandem solar cells. Herein, an indium tin oxide interlayer is deposited between ETL and TCO to address this issue. Specifically, the interlayer is prepared using an all-physical and H2O-free method, electron-beam evaporation, which can avoid any potential damage to the underlying perovskite and ETL layers. Moreover, the interlayer's composition can be readily tuned by changing the evaporator component, enabling authors to regulate the contact resistance and energy-level alignment of the ETL/TCO interface. Consequently, the resultant perovskite/silicon tandem solar cells exhibit an impressive power conversion efficiency (PCE)of 30.8% (certified 30.3%). Moreover, the device retains 98% of its initial PCE after continuous operation under ambient conditions for 1078h, representing one of the most stable and efficient perovskite/silicon tandem solar cells.

Several common methods of making vesicles (except an emulsion method) capture intended lipid ratios

Researchers choose different methods of making giant unilamellar vesicles to satisfy different constraints of their experimental designs. A challenge that arises when researchers use a variety of methods is that each method may produce vesicles with a different average lipid ratio, even if all experiments use lipids from a common stock mixture. Here, we use mass spectrometry to investigate ratios of lipids in vesicle solutions made by five common methods: electroformation on indium tin oxide slides, electroformation on platinum wires, gentle hydration, emulsion transfer, and extrusion. We made vesicles from either five-component or binary mixtures of lipids chosen to span a wide range of physical properties: di(18:1)PC, di(16:0)PC, di(18:1)PG, di(12:0)PE, and cholesterol. For a mixture of all five of these lipids, ITO electroformation, Pt electroformation, gentle hydration, and extrusion methods result in only minor shifts in lipid ratios (≤5 mol %) relative to a common stock solution. In contrast, emulsion transfer results in ∼80% less cholesterol than expected from the stock solution, which is counterbalanced by a surprising overabundance of saturated PC-lipid relative to all other phospholipids. Experiments using binary mixtures of saturated and unsaturated PC-lipids and cholesterol largely support results from the five-component mixture. In general, our results imply that experiments that increment lipid ratios in small steps will produce data that are highly sensitive to the technique used and to sample-to-sample variations. For example, sample-to-sample variations are ∼±2 mol % for five-component vesicles produced by a single technique. In contrast, experiments that explore larger increments in lipid ratio or that seek to explain general trends and new phenomena will be less sensitive to sample-to-sample variation and the method used.

Impact of ambient moisture on gate controllability in ferroelectric-gate field-effect transistors with bottom-gate geometry

Ferroelectric-gate field-effect transistors (FeFETs) with a bottom-gate geometry consisting of a ferroelectric HfO2 gate and an oxide channel have been intensively studied in recent years. However, there has been no detailed investigation into the impact of atmospheric exposure on device performance, even though the channel is often exposed to ambient air for process simplification, especially at the research stage. In this study, the ambient stability of an indium tin oxide channel FeFET with a ferroelectric Ce-HfO2 bottom gate was investigated. We found that ambient degradation of the gate controllability was caused by an increase in physisorbed water in the device owing to the intrusion of moisture. Mobile ions, such as H+, which can easily move through a network of hydrogen bonds formed by adjacent physisorbed water, may compensate for ferroelectric polarization. Finally, we demonstrated that the observed degradation can be managed effectively without compromising the original device characteristics using Al2O3 passivation gently formed via plasma-free deposition.

Simulation of perovskite solar cell with transparent contacts for solar windows

In recent years, halide-based perovskite solar cells (PSC) have caught worldwide attention since their power conversion efficiency (PCE) has surpassed 25% with low fabrication cost and high scalability. The semi-transparent PSC (ST-PSC) is suitable for building-integrated photovoltaic (BIPV) applications, especially for solar windows. The ST-PSC must demonstrate a reasonable balance between PCE and transparency in the visible region for solar windows, which is inversely proportional to each other. This work studies ST-PSC based on methylammonium lead triiodide (MAPbI3) as solar windows using the General-Purpose Photovoltaic Device Model (GPVDM) and OPAL 2 as the simulation platforms. Parameters such as methylammonium lead triiodide (MAPbI3) thickness, silver (Ag) contact thickness and indium tin oxide (ITO) transparent contact thickness are investigated in relation to the PCE and average visible transmission (AVT). The results demonstrate that the ST-PSC with MAPbI3 thickness of 500 nm and ITO bottom transparent contact of 100 nm leads to PCE of 22.85% and AVT of 11.36%. These parameters represent the best results obtained in this work.

High efficiency ultra-broadband absorber and thermal emitter for the composite Ag-NPs/SiO2/MXene multilayer structure on ITO substrate

n this paper, we presented an Ag-NPs/SiO2/MXene plasma model consisting of an MXene layer, a silicon dioxide (SiO2) layer with silver nanoparticles (Ag-NPs) as well as an indium tin oxide (ITO) substrate. The light absorption and thermal radiation of the Ag-NPs/SiO2/MXene plasma model were investigated by finite-difference time-domain (FDTD) and experimental methods. The results showed that due to the localized surface plasmon resonance (LSPR) generated on the surface of Ag-NPs, the maximum absorption of the Ag-NPs/SiO2/MXene plasma model in the visible and near infrared could reach 99.99 %, and the ultra-high wide-angle absorption from 0° to 60° was achieved, and the simulated data were in good agreement with the experimental data. Finally, we calculated that the Ag-NPs/SiO2/MXene model was 93.0 % ultra-efficient thermal emissivity at 1200 K using Planck’s law theory. Broadband absorption and thermal emission of the Ag-NPs/SiO2/MXene structure of importance in the field of light absorption.

Exoelectrogenic behaviors of Shewanella oneidensis MR-1 and cytochrome knock-out mutants on smooth electrodes of different materials

The development of anodes supporting a high rate of current generation stands as a crucial and challenging aspect in microbial electrochemical systems. A well-defined electrode surface morphology is essential for comprehending the impact of material intrinsic properties on microbial current generation, offering molecular insights into the respiration of exoelectrogens with electrodes made of diverse materials. We fabricated smooth electrodes (root mean square roughness below 10 nm) using four materials, each representing a distinct class of materials commonly utilized to construct bioanodes. These electrodes were employed to investigate current generation, electrochemical characteristics, and biofilm formation by Shewanella oneidensis MR-1 and mutants lacking cytochromes MtrC (ΔmtrC), MtrA (ΔmtrA), or CymA (ΔcymA). In reactors inoculated with MR-1, the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate electrodes demonstrated a current density of 12.5 ± 1.1 μA cm-2, surpassing the 3.57 ± 0.50 μA cm-2 observed with indium tin oxide electrodes, while current generation levels by gold and glassy carbon electrodes fell in between. This disparity was not attributed to distinct biofilm formations by MR-1, as it formed stable monolayer biofilms on all types of working electrodes. At least five electron transfer pathways were identified in the MR-1 Vammograms, with the activities of these pathways depending on the electrode materials. The effectiveness of both endogenous and exogenous electron mediators varied with the electrode materials involved. Additionally, a phenazine compound exhibited diverse formal potentials when interacting with the biofilm and different types of electrodes. The mutants displayed varying degrees of impaired current generation and biofilm formation capabilities, with ΔmtrA and ΔcymA being the most affected regardless of the electrode used. However, for a specific mutant, the overall current generation, relative contribution by individual pathways, and biofilm formations underwent significant changes based on the electrode materials employed.