Hybrid Devices Research Articles

Regulating the Conformational and Macroscopic Properties of Inorganic Nanowires by Polymer Grafts

AbstractUltrathin inorganic nanowires are an emerging class of building blocks for creating functional materials and devices, but there remains challenging to fine‐tune the structure and property of the nanowires at the molecular level. Here, this work shows that ultrathin polymer‐grafted gold nanowires (PG‐AuNWs) can exhibit bottlebrush polymer‐like physical behaviors and macroscopic properties. The hybrid PG‐AuNWs in solutions show polymer‐like viscoelasticity which can be finely regulated by controlling the structural parameters (e.g., length of the AuNWs, molecular weight of grafted polymers) of the PG‐AuNWs, the environmental conditions (e.g., temperature, solvent compositions), and the aging time. Furthermore, this work unravels at the molecular level that the conformational properties (e.g., contour length, persistence length, and mean‐squared radius of gyration) of the PG‐AuNWs can be correlated to their structural parameters following similar power‐law relations as molecular bottlebrush polymers. This work bridges the fundamental gap between polymer‐like inorganic nanowires and bottlebrush polymers, thus accelerating the development of new nanowire‐based functional hybrid materials and devices.

Bimodal Gating Mechanism in Hybrid Thin-Film Transistors Based on Dynamically Reconfigurable Nanoscale Biopolymer Interfaces.

In recent years, increased control over naturally-derived structural protein formulations and their self-assembly has enabled the application of high-resolution manufacturing techniques to silk-based materials, leading to bioactive interfaces with unprecedented miniaturized formats and functionalities. We present here a hybrid biopolymer-semiconductor device obtained by integrating nanoscale silk layers in a well-established class of inorganic field-effect transistors (silk-FETs). The devices offer two distinct modes of operation - either traditional field-effect or electrolyte-gated - enabled by the precisely controlled thickness, morphology and biochemistry of the integrated silk layers. The different operational modes are selectively accessed by dynamically modulating the free-water content within the nanoscale protein layer from the vapor phase. The utility of these hybrid devices is illustrated in a highly sensitive and ultrafast breath sensor, highlighting the opportunities offered by the integration of nanoscale biomaterial interfaces in conjunction with traditional semiconductor devices, enabling functional outcomes at the intersection between the worlds of microelectronics and biology. This article is protected by copyright. All rights reserved.

Effect of temperature on redox active sites in sulfide based nanorods composites electrode material in a hybrid supercapacitor for energy storage and biomedical applications

Bimetallic sulfide based electrode materials have attained a lot of interest because of high chemical activity, large conductivity and porous structure. This work effectively described the impact of temperature on the specific capacity of electrode materials and is successfully used to study biomedical applications by detecting hydrogen peroxide. The high oxidation-reduction reactions and conductivity of transition metal-based electrode materials have been recognized as being advantageous for supercapacitor (SC) electrodes; however, the temperature-dependent behavior of CoMgS-based electrodes is not yet fully understood. To address this knowledge gap, CoMgS electrodes were prepared using hydrothermal process, and their electrochemical performance was characterized at various temperatures (0–55 °C). Notably, the CoMgS-based electrode materials exhibited excellent electrochemical performance at 55 °C, displaying a specific capacity (Cs) of 900.0C/g at 10 mV/s using a three-electrode system. Moreover, the CoMgS and activated carbon-based hybrid device demonstrated remarkable Cs of 293.6C/g at the temperature of 55 °C with attractive energy and power densities of 30.6 Wh/kg, and 5183 W/kg, respectively. Even after undergoing 5000 cycles, the CoMgS//AC device exhibited a capacity retention (CR) rate of 85 %, indicating its exceptional durability as an energy storage solution. Besides, the composite devices are used to detect hydrogen peroxide which exists in enough amounts in cancerous cells. Overall, the findings of this work indicate that CoMgS electrode capacitance may be increased at an optimal temperature, probably as a result of better ion diffusion and charge transfer kinetics, to improve the efficiency of the energy storage device and be utilized to identify the cancerous part in the body.

Recent Advances in Functional Fiber-Based Wearable Triboelectric Nanogenerators.

The quality of human life has improved thanks to the rapid development of wearable electronics. Previously, bulk structures were usually selected for the fabrication of high performance electronics, but these are not suitable for wearable electronics due to mobility limitations and comfortability. Fibrous material-based triboelectric nanogenerators (TENGs) can provide power to wearable electronics due to their advantages such as light weight, flexibility, stretchability, wearability, etc. In this work, various fiber materials, multiple fabrication methods, and fundamentals of TENGs are described. Moreover, recent advances in functional fiber-based wearable TENGs are introduced. Furthermore, the challenges to functional fiber-based TENGs are discussed, and possible solutions are suggested. Finally, the use of TENGs in hybrid devices is introduced for a broader introduction of fiber-based energy harvesting technologies.

Fully Printed Electrolyte‐Gated Transistor Formed in a 3D Polymer Reservoir with Laser Printed Drain/Source Electrodes

AbstractIn solution processed electronic devices it is crucial that the deposited inks are properly aligned and that all post‐processing steps are compliant with each other. Moreover, shorter channel lengths are highly beneficial to increase the device performance. Herein, laser printing of metals and polymer reservoirs allows to print sub‐micrometer sized channel lengths while confining functional inks into these small gaps. Therefore, a manufacturing concept and optimized material stack, suitable for combined inkjet and laser printing are proposed. A nanoparticulate indium oxide (In2O3) semiconductor is inkjet printed into and constrained by a 3D laser written polymer (pentaerythritol triacrylate, PETA) reservoir. Inside the 3D printed polymer reservoir, platinum (Pt) electrodes, that are further routed over the reservoir walls, are laser printed by a metal reduction process. The transistor fabrication is completed by a second inkjet printed layer of composite solid polymer electrolyte and an organic top‐gate layer (PEDOT:PSS). This concept does not exceed annealing temperatures higher than 100 °C, and is compatible with a range of substrates. The characterized electrolyte‐gated field‐effect transistor show a reasonable on/off‐ratio in the range of 104 with negligible leakage currents. This materials and hybrid device manufacturing scheme has believed great potential for bioelectronics, lab‐on‐a‐chip applications and others.

Evaluating the feasibility of the spinel-based Li4Ti5O12 and LiNi0.5Mn1.5O4 materials towards a battery supercapacitor hybrid device

Hybrid devices consisting of energy-dense lithium-ion battery chemistry and power-dense supercapacitors in a single unit cell are vital to improve the energy density of supercapacitors. Herein, we demonstrate a lithium-ion capacitor containing a composite of LiNi0.5Mn1.5O4 and a high surface area carbon composite as the cathode and carbon-coated Li4Ti5O12 as an anode. The composite cathode combines redox and adsorption mechanisms to store ions, producing more capacity. In contrast, the nanostructure anode can store Li-ions through a faster diffusion-type intercalation process. As a result, the lithium-ion capacitor delivers energy densities of 48 and 30 Wh kg−1 at power densities of 250 and 7900 W kg−1, respectively. Furthermore, upon cycling at 1 A g−1, the full cell retains ∼70 % specific capacitance till 4000 cycles. The use of spinel materials in both electrodes boosts the electrochemical performances of this lithium-ion capacitor because of their inherent properties like stable phase and 3D network-type structure for Li-ion diffusion. Additionally, battery-type cathodes like LiNi0.5Mn1.5O4 (4.7 V vs. Li/Li+) with a wider potential window improve the energy density, whereas better safety and cycling stability arise from the zero-strain Li4Ti5O12 anode. The studies on impedance, self-discharge, and leakage current analyses prove the practical feasibility of the lithium-ion capacitor.

Electrical, thermal and thermoelectric transport in open long-range Kitaev chain

We study electrical, thermal and thermoelectric transport in a hybrid device consisting of a long-range Kitaev (LRK) chain coupled to two metallic leads at two ends. Electrical and thermal currents are calculated in this device under both voltage and thermal bias conditions. We find that the transport characteristics of the LRK chain are distinguishably different from its short-range counterpart, which is well known for hosting zero energy Majorana edge modes under some specific range of values of the model parameters. The emergence of massive Dirac fermions, the absence of gap closing at the topological phase transition point and some special features of the energy spectrum which are unique to the LRK chain, significantly alter electrical/thermal current vs. voltage/temperature bias characteristics in comparison with that of the short-range Kitaev chain. These novel transport characteristics of the LRK model can be helpful in understanding nontrivial topological phases of the LRK chain.

Engineering of binder-free cobalt carbonate hydroxide hydrate nanostructure for high-performance hybrid supercapacitors

Cobalt-based binder-free electrode materials, such as Co(CO3)0.5(OH)⋅0.11H2O nanowires (Co@Urea) and Co(OH)F microcrystals (Co@NH4F), were synthesized on a nickel foam substrate by a traditional hydrothermal method using urea and ammonium fluoride (NH4F) as the complexing reagents. The nanowire structure of the Co@Urea electrode promoted efficient charge transfer and high electrochemical active centers. The Co@Urea electrode exhibited a large specific capacity (693.0 C g−1 at 1 A g−1), better rate performance (50.8 % after 20 A g−1), and exceptional cyclic durability (84.0 % capacity retention after 10,000 cycles) compared to Co@NH4F electrode in a three-electrode configuration. A hybrid supercapacitor device was fabricated with Co@Urea as the cathode and activated charcoal as the anode, exhibiting high specific energy and specific power of 53.8 Wh kg−1 and 799.9 W kg−1, respectively. Furthermore, this hybrid device shows excellent long-term stability with 88.2 % capacity retention after 10,000 cycles at a current density of 40 A g−1. This study proposes developing binder-free cobalt-based compounds for electrochemical energy storage applications.

Universal material trends in extraordinary magnetoresistive devices

Extraordinary magnetoresistance (EMR) is a geometric magnetoresistance emerging in hybrid systems typically comprising a high-mobility material and a metal. Due to a field-dependent redistribution of electrical currents in these devices, the electrical resistance at room temperature can increase by 107% when applying a magnetic field of 5 T. Although EMR holds considerable potential for realizing sensitive, all-electronic magnetometers, this potential is largely unmet. A key challenge is that the performance of EMR devices depends very sensitively on variations in a vast parameter space where changes in the device geometry and material properties produce widely different EMR performances. The challenge of navigating in the large parameter space is further amplified by the poor understanding of the interplay between the device geometry and material properties. By systematically varying the material parameters in four key EMR geometries using diffusive transport simulations, we here elucidate this interplay with the aim of finding universal guidelines for designing EMR devices. Common to all geometries, we find that the sensitivity scales inversely with the carrier density, while the MR reaches saturation at low carrier densities. Increasing the mobility beyond 20 000 cm2 Vs−1 is required to observe strong EMR effects at 1 T with the optimal magnetoresistance observed for mobilities between 100 000–500 000 cm2 Vs−1. An interface resistance below cm2 between the constituent materials in the hybrid devices was also found to be a prerequisite for very high magnetoresistances in all geometries. By further simulating several high-mobility materials at room and cryogenic temperatures, we conclude that encapsulated graphene and InSb are amongst the most promising candidates for EMR devices showing high magnetoresistance exceeding 107% below 1 T at room temperature. This study paves the way for understanding how to realize EMR devices with record-high magnetoresistance and high sensitivity for detecting magnetic fields.

Metal/bacteria cellulose nanofiber bilayer membranes for high-performance hydrovoltaic electric power generation

Hydrovoltaic devices that produce electricity from water represent a promising solution for green energy harvesting. Hydrovoltaic power generators based on various emerging nanostructured materials have shown great potential in water-enabled electricity generation. However, the development of high-performance and practical hydrovoltaic devices remains limited because of low electric power generation, high cost of precursor materials, and complicated fabrication processes. In this study, we developed a novel metal-coated bacteria cellulose nanofiber bilayer membrane (MBCBM) for high-performance hydrovoltaic power-generation devices. The top side of the MBCBM has metal-bacteria cellulose (BC) nanofibers that serve as a conducting electrode for fast charge carrier collection, whereas the bottom side has BC nanofibers that serve as hydrovoltaic materials for high efficient energy generation. A Schottky barrier was incorporated into the hydrovoltaic device, which enhanced the electric power output. Experiments revealed that the optimized single-MBCBM based hydrovoltaic device generated a maximum voltage of 0.935 V, current of 7.51 mA, and power output of 6.07 mW with a 50 μl electrolyte solution. The hybrid membrane and device design concept is expected to effectively utilize practical sustainable and clean energy sources for Internet of Things (IoT) devices and self-powered wearable devices in next-generation electronics.

Design and development of a piezoelectric-hydraulic hybrid actuator with quarter-wavelength tubes

The piezoelectric hydraulic actuator is a hybrid device consisting of a hydraulic pump driven by a piezoelectric stack connected to a hydraulic cylinder. For this type of piezoelectric actuator, the inertial force caused by the flow pulsation of the liquid will inhibit the movement of the piezoelectric vibrator and reduce its output performance. To solve these issues, two tubes were embedded into the piezoelectric-hydraulic hybrid actuation system for the first time to act as mechanical bandstop filters by interfering with the propagation of acoustic waves. The acoustic power transmission loss of the tube is derived from the one-dimensional wave equation. According to the experimental results, when the excitation frequency is close to the optimal operating frequency corresponding to the tubes, the liquid pulsation rate is reduced, the influence of inertial force on the actuator is weakened, and the output performance is relatively significantly improved. This strategy finally leads to a maximum no-load velocity of 153.5 mm s−1 and a maximum blocking force of 261.5 N for the hybrid actuator with 300 mm tubes; the maximum no-load velocity and blocking force of the hybrid actuator with 500 mm tubes are 94.45 mm s−1 and 230 N, respectively. Furthermore, this strategy can be used in other electrohydraulic actuators to enhance their capabilities.

Elevates the electrochemical stability performance of hydrothermally synthesized Co3O4 nanowires/NF for hybrid supercapacitors

Transition metal oxide considered as the aspicious electrodes that are embraced as huge attention in the recent years due to its vast unique properties. In this research work, the 1D-Co3O4 nanowires were grown on the Ni-foam (NF) by simple hydrothermal method followed by annealing process for supercapacitor application. The obtained Co3O4 nanowires/NF electrode demonstrates the highest specific capacitance of 1767.27 F g−1 with 97 % stability retention after 5000 GCD counts. In addition, the hybrid supercapacitor device was employed using with Co3O4 nanowires/NF as the positive electrode and chemically synthesised nitrogen doped g-C3N4 (N@g-C3N4) as the negative electrode, respectively. The constructed device (Co3O4/Ni||N@g-C3N4) revealed to attain the energy and power densities of 22.26 W h kg−1 and 4000 W kg−1, with 82.4 % stability retention within the optimum 1.6 V cell voltage. These electrochemical results of the designed hybrid device was valid as a highly potential in the various electronic devices.

Influence of microstructure and thermoelectric properties on the power density of multi-walled carbon nanotube/ metal oxide hybrid flexible thermoelectric generators

The quest for a low-cost, flexible thermoelectric generator using eco-friendly metal oxide-based materials for low-temperature applications has motivated this work. The work compares the performance of amine-functionalized multi-walled carbon nanotubes (MWCNT-NH2) and metal oxide nanoparticles (CuO, NiO, and Fe2O3) ink-based hybrid flexible thermoelectric generators. Study reveals that the thermoelectric performance of a flexible thermoelectric generator improves by fine-tuning the materials crystallite size, bandgap, carrier concentration, carrier mobility, resistivity, the Seebeck coefficient, and micro-porosity of the ink film, which could be materialized by using hybrid thermoelectric materials. Among the three fabricated devices, MWCNT-NH2/NiO hybrid flexible thermoelectric generator exhibits a maximum power output of 1.44 nW at ΔT= 100 °C. The maximum power density displayed by MWCNT-NH2/NiO hybrid device is 59.3 nW/cm2 at ΔT= 100 °C, which is 23.28% and 332.8% higher than that of MWCNT-NH2/CuO and MWCNT-NH2/Fe2O3-based devices, respectively. The performance of MWCNT-NH2/NiO is comparatively superior to some previously reported works.

Supercapacitance of an integrated structure of nickel cobalt metal-organic framework decorated on electrospun functionalized carbon nanofiber

In order to enhance the electrochemical efficiency of supercapacitors, novel active electrode materials are being developed. This study provides a unique method to synthesize an integrated structure consisting of a nickel-cobalt metal-organic framework (NiCo-MOF) on functionalized carbon nanofiber (f-CNF) utilizing a single-step solvothermal method. Physicochemical characterization confirmed the successful synthesis of the integrated system of NiCo-MOF@f-CNF. This novel structure has the potential to significantly improve the electrochemical properties of the initially prepared material for use in supercapacitors. The synthesized electrode has a higher specific capacitance/capacity value of 788 F g−1 (315.2 C g−1) at 1 A g−1 and high cycling stability. The developed hybrid device exhibited a promising specific energy of 8.6 Wh kg−1 and a high specific power of 1147 W kg−1, demonstrating potential for practical applications. The current study suggests that the proposed material can be a viable electrode for high-efficiency supercapacitors.

Conceptual design and optimisation of a novel hybrid device for capturing offshore wind and wave energy

AbstractThe access to the offshore wind resource in the deep sea requires the development of innovative solutions which reduce the cost of energy. Novel technologies propose the hybrid combination of wind and wave energy to improve the synergy between these technologies sharing costs, such as mooring and electrical connexion. This work proposes a novel hybrid wind and wave energy system integrating a floating offshore wind turbine with three-point absorbers wave energy converters (WECs). The WECs are an integral part of the floating structure and contribute significantly to the hydrostatic and dynamic stability of the system. Their geometry is optimised considering a cylindrical, semi-cylindrical and spherical shape for the Pantelleria case study. The cylindrical shape with the largest radius and the lowest height is the optimal solution in terms of reducing structural costs and maximising the performance of the WECs. The in-house hydrostatic stability tool and the time domain model MOST are used to optimise the WECs, with a combined meta-heuristic genetic algorithm with the Kriging surrogate model and a local Nelder–Mead optimization in the final simulations. The power of the WECs is estimated with both linear and variable motor flow hydraulic PTOs to obtain a more realistic electrical power generation. Generally, the hybrid device proved to be more competitive than the floating wind turbine alone, with a LCOE reduction up to 11%. Performance of the hybrid device can be further improved when more energetic sites are considered, as the energy generated by the WECs is higher.

Position control based on Gaussian function applied on magneto-rheological fluid disc brake of a hybrid mechanical device (MR brake - DC motor)

This article presents an angular position control, based on the Gaussian function, of a Magneto-Rheological fluid disc brake (MR brake) driven by a DC motor. Our proposed control strategy is to apply a continuous magnetic flux density to the MR brake, which will be maximum when the proportional controller of the DC motor reaches the desired position to brake the hybrid device. The MR brake controller activates a braking torque that adopts the behavior of the Gaussian function instead of a pulsed braking torque as provided by other commonly used controllers (On-Off controllers). The response of the MR brake controller, which is presented in a closed-loop feedback system, depends on the angular position error of the shaft and a tuning parameter representing the critical angular position at which the magnetic flux density, which is applied to the MR brake, reaches 60.65% of its maximum value. The advantage is to avoid knowing the dynamic parameters, such as the inertia of the mechanical device or its speed, and to reject these perturbations by a simple tuning parameter of the MR brake. To show the effectiveness of the proposed controller, the dynamic model of a slider-crank mechanism is considered. The results showed similar behavior as conventional controllers, where overshoot and oscillations were minimized. This behavior has been obtained in other research articles using controllers that require a greater amount of data processing.

Review, Comprehensive Analysis and Derivation of Analytical Power Loss Calculation Equations for Two- to Three-Level Midpoint Clamped Inverter Topologies with Hybrid Switch Configurations

Increased performance requirements in new power electronics areas of application, such as electric aircraft, make innovations on different design levels necessary. In order to quickly compare different topologies, analytical loss equations provide a fast and straightforward way to narrow down the possible solution space. The approach widely used in the literature results in long and complex terms, which can only be compared between different literature sources with great effort. Moreover, the literature lacks a detailed summarizing description of these analytical equations and their derivation, starting from the standard two-level VSI up to three-level midpoint clamped inverter topologies, such as the ANPC topology in its different modulation schemes. The application of such higher-level inverter topologies allows hybrid device configurations to become performant solutions. This work aims to give a closed-form description of the analytical loss modeling and the theoretical background and provide an implementation approach for a wide span of inverter topologies and for different modulation methods.

Rapid cold plasma synthesis of cobalt metal–organic framework/reduced graphene oxide nanocomposites for use as supercapacitor electrodes

Metal–organic frameworks (MOFs) are recognized as a desirable class of porous materials for energy storage applications, despite their limited conductivity. In the present study, Co-MOF-71 was fabricated as a high-performance supercapacitor electrode at ambient temperature using a fast and straightforward, one-pot cold plasma method. A supercapacitor electrode based on Co-MOF@rGO was also synthesized by adding reduced graphene oxide (rGO) during processing to increase the capacitance retention and stability after 4000 cycles from 80 to 95.4%. The Co-MOF-71 electrode provided a specific capacitance (Cs) of 651.7 Fg−1 at 1 Ag−1, whereas the Co-MOF@rGO electrode produced a Cs value of 967.68 Fg−1 at 1 Ag−1. In addition, we fabricated an asymmetric device (Co-MOF@rGO||AC) using Co-MOF-rGO as a high-rate positive electrode and activated carbon (AC) as a negative electrode. This hybrid device has a remarkable specific energy and power density. The combination of MOFs with reduced graphene oxide (rGO) in a cold plasma environment resulted in the formation of a three-dimensional nanostructure composed of nanosheets. This nanostructure exhibited an increased number of electroactive sites, providing benefits for energy storage applications.

Nanostructured SnS-Si hybrid photodetectors by pulsed laser processed nanocolloids

This research investigates the fabrication of SnS-Si hybrids for photodetection and photocatalysis using nanocolloids of tin sulfide (SnS), monocrystalline silicon (Sim) and polycrystalline silicon (Sip) produced by laser-assisted techniques (pulsed laser fragmentation as well as ablation in liquid). Characterization of the nanocolloids and the hybrid thin films obtained by techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron Spectroscopy (XPS), Raman spectroscopy, UV–Visible spectroscopy and photoluminescence spectroscopy (PL) are presented in this work. Post-deposition annealing improved the material properties of the hybrid films and the films exhibited optical bandgaps between 1.51 and 1.68 eV, suitable for light detection. In the case of hybrid SnS-Si films, SnS-Sim showed two orders of current higher than the SnS-Sip films. The photocurrent dynamic curves (current vs time) and current-voltage (I–V) characteristics are investigated to verify the improved device performances. The photodetector parameters such as sensitivity, responsivity, detectivity are also reported. Compared with conventional SnS thin film devices, all the films (SnS and SnS-Si hybrids) in this work responded to illumination sources of wavelengths up to 1064 nm. This is one of the initial studies on hybrid devices with Si nanoparticles for photodetector applications. All the films showed ultra-short response/recovery times in the range of 400–800 ms and their photodetector parameters were recorded. The films demonstrated good stability and cyclic photocatalytic activity to visible light.

InP Quantum Dots Tailored Oxide Thin Film Phototransistor for Bioinspired Visual Adaptation

AbstractThe exploration of bionic neuromorphic chips, capable of processing sensory data in a human‐like manner, is both a trend and a challenge. There is a strong demand for phototransistors that offer broadband in‐sensor adaptability. This study introduces a bioinspired vision sensor based on InP quantum dots (QDs)/InSnZnO hybrid phototransistors. This novel design combines the excellent electrical transportation features of oxide semiconductors with the superior optoelectronic response of InP QDs. The resulting hybrid devices exhibit exceptional gate controllability and a robust visible‐light response. These characteristics enable the emulation of multiple functions of the human visual system and the accommodation of varying light intensity environments. Furthermore, the phototransistor array successfully replicates the scotopic and photopic adaptation recognition behaviors of the human retina. Notably, the device demonstrates faultless competency in image processing, achieving an impressive 93% accuracy for digit recognition. These findings contribute to the advancement of bionic neuromorphic chips and offer promising opportunities for future developments in the bioinspired visual system.