Dual-function Device Research Articles

Portable dual-functional hygroscopic device for efficient atmospheric water harvesting and hydrogen production in diverse environments

Portable dual-functional hygroscopic device for efficient atmospheric water harvesting and hydrogen production in diverse environments

Enhanced antibacterial testing and latent fingerprint detection using dichlorofluorescein-doped carbon dots

This research presents an innovative multifunctional reagent consisting of dichlorofluorescein-doped carbon dots (CDs-DC) generated from fresh coconut water by a hydrothermal method. This work’s innovation resides in the simultaneous application of CDs-DC for latent fingerprint detection on nonporous surfaces and improved antibacterial efficacy. The incorporation of dichlorofluorescein into the CDs matrix enhances photoluminescent characteristics and improves antibacterial effectiveness against Gram-positive and Gram-negative bacteria (Escherichia coli, Serratia marcescens, Bacillus megaterium, Staphylococcus aureus). The addition of a starch matrix significantly strengthened this combination, enhancing the adherence and recognition of complex fingerprint patterns under UV light. Furthermore, the CDs-DC demonstrated significant reactive oxygen species (ROS) production, enhancing their antibacterial efficacy. This dual-functional device represents a notable progression in forensic science and antibacterial technology, establishing itself as a sustainable and highly efficient instrument for these purposes.

Detection of overhead line glass insulator condition using dual function device and deep learning approach

This paper presents a design of a multifunction smart wireless device for online condition monitoring of transmission line insulators. The proposed device can measure the insulator leakage current and take images of the high-voltage insulation. Yolov5-based models and deep convolutional neural networks (DCCN) are developed to analyze and classify the measured data and estimate the insulator's health condition. We have developed and tested a prototype of the proposed device. The device can issue a real-time warning message when a sudden change takes place in the leakage current value. The control center or smartphones receive the collected data wirelessly. We analyze the transmitted data using the developed methods to detect any anomalies and take appropriate remedial action. The performance and feasibility of the developed device are assessed through extensive experimental analysis. Results attest to the robustness of the proposed device, which is easy to install for existing and future overhead transmission line insulators.

Organic Dye Molecule Intercalated Prussian Blue for Simultaneously Enhancing Coloration Efficiency and Energy Storage Capacity in Electrochromic Battery.

The dual-functional device combining electrochromic properties and energy storage has gained numerous attentions in the field of energy-saving smart electronics. However, achieving simultaneous optimization of coloration efficiency and energy storage capacity of materials poses a significant challenge. This study presents a novel approach by incorporating methyl orange into Prussian blue channels (PB-MO films) to adjust the internal electronic structure of Prussian blue. This modification allows the active layer to simultaneously improve the electrochromic and energy storage performance. The introduction of methyl orange not only alters the ratio of Fe3+/Fe2+ within the framework through the coordination reaction of Fe3+ with methyl orange, but also improves the reaction kinetics after intercalating organic dye molecules, including charge transfer resistance, diffusion capability of ions and capacitive contribution. The PB-MO films demonstrate remarkable properties: high optical contrast (81.4% at 670nm), excellent coloration efficiency (265 cm2C-1), and significant specific capacity (84 mAh m-2 at 0.05 A m-2), outperforming pure PB films. The PB-MO films are ideally suited for applications in displays and intelligent energy storage fields, boasting both high coloration efficiency and substantial energy storage capacity, thus advancing promote the development of dual-functional electrochromic devices.

A dynamically switchable and tunable metamaterial device based on vanadium dioxide and Dirac semimetal

In this paper, a dual-function metamaterial device based on vanadium dioxide (VO2) and Dirac semimetal (DS) operating in terahertz (THz) frequency range is designed. The reversible phase transition properties of VO2 are exploited to achieve the dynamic switch between the function of broadband absorption and broadband polarization conversion. It is demonstrated that when VO2 is in the metallic state and the Fermi energy level () of DS is set to 30 the broadband absorption in the operating frequency range of 1.42-3.40 THz can be achieved, and its absorbance exceeds 90% with a relative bandwidth of 82.16%. When VO2 is in the insulating state and the of DS is set at 180 , the high efficient broadband polarization conversion can be obtained in the operating frequency range of 2.08-4.88 THz and the polarization conversion ratio (PCR) is greater than 90% with a relative bandwidth of up to 80.46%. Therefore, the proposed switchable dual-functional THz device can be extensively utilized in absorption, polarization conversion and other potential fields.

Modified extended Rauch–Tung–Striebel smoother method for the dynamic external excitation identification of piezoelectric vibration energy harvesting systems

A vibration energy harvester can collect vibration energy from the environment to supply low-power devices, such as wireless sensor nodes. Reducing the size and power consumption of these devices is a challenging problem. A dual-function device, which includes energy harvesting and vibration measurement, may solve this problem. Therefore, studying inversion methods for identifying the external excitation of a harvester is meaningful. In this study, a modified inversion method that combines an extended Rauch–Tung–Striebel smoother (ERTSS) with the particle swarm optimization (PSO) algorithm, i.e., the ERTSS-PSO method, is proposed to identify the time domain signal of external excitation through the voltage response of a piezoelectric vibration energy harvester. A modified ERTSS approach with sliding windows is developed. The sliding windows are partially overlapped to eliminate identification errors between the two contiguous windows. Near real-time identification is achieved for the small sliding window. PSO is utilized to estimate state noise covariance and measurement noise covariance, improving identification accuracy compared with the L-curve approach. Under this proposed framework, prior knowledge regarding the statistical data of unknown external excitations is unnecessary, enabling a more comprehensive range of applications. To assess the performance of the proposed ERTSS-PSO method, numerical simulations, including two piezoelectric vibration energy harvesting systems with third-order and fifth-order nonlinear stiffness, are conducted to verify the effectiveness of the proposed method under harmonic, multifrequency, and random excitations. The method proposed in this study is also validated by a circular laminated piezoelectric plate harvester under harmonic and random excitations in an experiment. Results from the experimental studies demonstrate that the proposed method improves identification accuracy by at least 9% compared with the extended Kalman filter, at least 7% compared with the augmented Kalman filter (AKF) with Rauch–Tung–Striebel smoother (ARTSS), and at least 40% compared with AKF under random excitation. In addition, the proposed method is unaffected by initial conditions, and it is more stable and accurate than AKF and ARTSS. The proposed method lays the theoretical foundation for identifying the external excitation of a harvester. It is also a possible solution for the miniaturization and compactness of wireless monitoring devices.

Ammonia controlled synthesis of NiO nanosheet arrays for high-performance electrochromic-supercapacitors

To optimize the synthesis process and improve the electrochromic and energy storage performance of NiO, in this paper, an ammonia hydrothermal method is used to prepare NiO nanosheet array electrodes with dual-functions of electrochromic and energy storage. When the concentration of ammonia reaches pH = 11.5, the prepared electrode exhibits optimal optical modulation capability (79.2 % at 620 nm). Additionally, this electrode also provides a large area specific capacitance (69.5 mF/cm² at 0.2 mA/cm²), good rate capability (maintaining 46.7 mF/cm² at 1.0 mA/cm²), and excellent capacitive stability (retaining 96 % of the initial capacitance after 5000 cycles). These excellent performances are mainly attributed to the hierarchical assembled nanosheets structure, which has a large active surface area and short ion transport paths. Furthermore, the uniform and interlinked self-assembled structure, as well as the preset seed layer significantly enhance the film's structural stability and the adhesion to the substrate. Notably, we also construct electrochromic-supercapacitors (ECSCs). During the charging process, two series-connected ECSCs turn dark brown and light up an LED lamp, while during the discharging process, the ECSCs gradually becomes colorless, and the LED lamp goes out. This study provides directions for the preparation of novel dual-functional visual energy storage materials and boosts the development of dual-functional electrochromic-energy storage devices.

Dual-Mode Semiconductor Device Enabling Optoelectronic Detection and Neuromorphic Processing with Extended Spectral Responsivity.

High-performance semiconductor devices capable of multiple functions are pivotal in meeting the challenges of miniaturization and integration in advanced technologies. Despite the inherent difficulties of incorporating dual functionality within a single device, a high-performance, dual-mode device is reported. This device integrates an ultra-thin Al2O3 passivation layer with a PbS/Si hybrid heterojunction, which can simultaneously enable optoelectronic detection and neuromorphic operation. In mode 1, the device efficiently separates photo-generated electron-hole pairs, exhibiting an ultra-wide spectral response from ultraviolet (265nm) to near-infrared (1650nm) wavelengths. It also reproduces high-quality images of 256×256 pixels, achieving a Q-value as low as 0.00437µWcm- 2 at a light intensity of 8.58µWcm- 2. Meanwhile, when in mode 2, the as-assembled device with typical persistent photoconductivity (PPC) behavior can act as a neuromorphic device, which can achieve 96.5% accuracy in classifying standard digits underscoring its efficacy in temporal information processing. It is believed that the present dual-function devices potentially advance the multifunctionality and miniaturization of chips for intelligence applications.

Nickel foam-loaded Co-MOF@TiO2/MoS2 as electrode materials for dual-function devices for glucose detection and hydrogen evolution.

Dual-functional nanomaterial electrodes have the capability to satisfy the requirements for both sweat analysis and the hydrogen evolution reaction (HER), thereby enabling the integration of electrochemical sensing and hydrogen production. In this study, ZIF-67 cubes are synthesized on nickel foam (NF), while TiO2 is obtained through an annealing process. Subsequently, the ZIF-67@TiO2/MoS2 nanocomposite is fabricated on nickel foam via a hydrothermal method. This composite material exhibits exceptional photocatalytic properties and is also suitable for the detection of glucose in sweat. The glucose detection range spans from 10nM to 10mM with a sensitivity of 7.24 μAmM-1cm-2 for a signal-to-noise ratio of 3 and a detection limit of 0.43μM. Moreover, when utilized as a hydrogen evolution electrode, this material demonstrates a current density of 10mAcm-2 at an overpotential of 118mV, with a Tafel slope of 73mV/dec. The synthesis process is both straightforward and economical. This research introduces a novel concept for the design of multifunctional chemical sensors.

Achieving solar-thermal driven dual functional device utilizing flexible PDA coated sponge integrated thermoelectric module design for water purification and power generation

The design of an efficient solar energy collector for solar-thermal-driven water purification and power generation is a promising strategy to concurrently mitigate the shortage of fresh water and energy crises. However, harvesting low-grade thermal energy in an eco-friendly and cost-effective manner through solar-thermal materials for water evaporation and electric cogeneration remains challenging. Herein, we demonstrate a dual-functional device integrating solar-thermally driven water purification and thermo-induced power generation. This typical design, fabricated via polydopamine (PDA) tightly deposited onto melamine sponges (PDA@Sponge) via H-bonds, along with a thermoelectric generator (PDA@Sponge/TEG), showcases superior solar-thermal-driven dual-functional application. The critically structurally adjustable PDA@Sponge possesses excellent homogeneity and stability, weakening interfacial hydrogen bonding between water molecules, favoring the evaporation and overflow of water molecules. The optimal serrated design achieves a water evaporation rate of up to ∼1.50 kg −2h−1, with an efficiency of ∼ 94.04 % under one sun, surpassing the most of previous reports, owing to its special tip thermal localization effect and rational water transportation management. Simultaneously, the designed PDA@Sponge/TEG yields an open-circuit voltage and short circuit current of 55 mV and 22 mA, respectively, along with a maximal output power of 162 μW (40.5 μW/cm2) at a load resistance of 7.5 Ω, under one sun and room temperature. Notably, such a device, after multiple series connections, can charge a capacitor to 1.5 V within 1 min, capable of powering low-energy electronic devices such as smartwatches and LED lights. By efficiently integrating of multiple solar-thermal-driven processes, our research promotes the design of multifunctional devices to promise an approach for desalinating seawater, purifying wastewater, and powering low-energy electronics, especially in remote areas lacking power stations and/or water treatment facilities.

Photovoltaic cooling and atmospheric water harvesting using a hygroscopic hydrogel

Photovoltaic power generation technology has gained significant attention from researchers due to its advantages of simple structure, environmental friendliness, and high sustainability. However, the photon-to-electron conversion efficiency (PCE) of photovoltaic (PV) panels is limited by the residual heat produced during the solar absorption process. Thus, an effective heat management is vital for the long-term stable and efficient photovoltaic system. In this paper, a novel dual-function device was proposed to realize effective cooling of PV panels and harvest freshwater from the air simultaneously. Through the utilization of evaporative cooling with hygroscopic hydrogel, the photovoltaic cooling-water generator (PVC-WG) device achieves up to 8 °C reduction in the operating temperature of PV panels along with a freshwater generation rate of 122.32 g m−2 h−1 in the laboratory at solar intensity of 1 kW m−2. At night, the hygroscopic hydrogel automatically absorbed moisture from the air to achieve self-regeneration, confirming its excellent reusability. Even in real outdoor environments, a maximum cooling effect of 9.2 °C and a stable freshwater generation of 98.08 g m−2 day−1 could be achieved. The system not only accomplishes thermal management for PV panels but also attains additional freshwater generation, which enhances the efficiency of harnessing the entire spectrum of solar energy.

Perovskite/organic tandem device to realize light detection and emission dual function

Developing highly integrated smart optoelectronic systems is vital to modern technology, yet critically challenging. This study introduces a tandem device that incorporates an organic photodiode (OPD) and a perovskite light emitting diode (PeLED), enabling simultaneous light detection and emission in one compact device, prepared by all-solution fabrication process. It shows that precise control of interfacial properties plays a critical role in establishing the all-solution processed OPD/PeLED multi-layered dual-function device which is critical for charge transport, recombination, and generation. The integrated structure allows for light detection and emission function selectively by controlling the polarity of the external bias. The optoelectronic performance of the dual-function tandem device is comparable to that of the discrete control OPD and PeLED, i.e., the tandem device achieves a responsivity of 94 mA/W at 850 nm under −1 V and a luminance result of 1319 cd/m2 at 516 nm under 7 V, which is comparable to 101 mA/W and 1983 cd/m2 for the control OPD and PeLED operated under the same conditions. This work demonstrates the promising properties of the monolithically integrated dual-functional device and its potential for application in health monitoring and wearable electronic devices.

Modification of the dual-function varistor-capacitor properties of Bi2/3Cu3Ti4O12 ceramic by doping with Sr0.99La0.01TiO3

Bi2/3Cu3Ti4O12 (BCTO) ceramic materials can be used as varistor-capacitor dual-function devices. In this research, Bi2/3Cu3Ti4O12-xwt%Sr0.99La0.01TiO3 (BCTO-xSLT) ceramic composites were prepared using the solid-state method. The microstructure, phase composition, and morphology along with the optical, dielectric, and nonlinear properties of ceramics were systematically investigated. All the samples exhibited the cubic perovskite structure. Notably, the grain size of BCTO decreased while its compactness increased at a small amount of incorporated SLT. Moreover, the SLT addition significantly decreased the dielectric loss (tanδ) with a prominent increase in the optical band gap (Eg) of ceramics. Interestingly, the dielectric constant (ε′) of the composites remained greater than 103, whereas the enhanced frequency and temperature stability as well as the nonlinear performance was observed as well. Among the various compositions, the sample with x = 0.06 showed the optimum dielectric and nonlinear properties with appreciably high ε′ of ∼11322, the lowest tanδ of ∼0.026 at 10 kHz, the highest nonlinear coefficient (α) of ∼7.49, the largest breakdown field strength (Eb) of ∼10.45 kV/cm, and the greatest energy storage density (w) of ∼54.2 mJ/cm3. These improved optical, dielectric, and nonlinear properties of the BCTO-SLT composites were attributed to the enhanced geometric (grain boundary number and compactness) and intrinsic (Eg, grain boundary resistance, and barrier height) properties of the grain boundary. The study demonstrates that BCTO-SLT ceramics can be potential candidates for capacitor-varistor dual-function devices.

A corn leaf based-strain sensor and triboelectric nanogenerator for running monitoring and energy harvesting

Recently, advanced wearable devices with posture sensing and energy harvesting have received widespread attention. Thus, we proposed a dual-function device (energy harvesting and running posture sensing), including carbon attached corn leaf strain sensor (CC-strain sensor) and a corn leaf-based triboelectric nanogenerator (C-TENG).According to the results, the relative resistance rate (ΔR/R0) exhibits linear characteristics in the three strain regions, and its linear coefficients are all above 0.96. Besides, at low strain rates from 0.01% to 0.1%, the CC-strain sensor can reach high sensitivity for monitoring weak signals, such as expressions in dance performances. The C-TENG device can achieve mechanical energy harvesting, providing a way to power low-power portable devices. From the results, the maximum power of C-TENG can arrive at 222 μW (resistance: 100 MΩ). This research can provide a new path to integrate strain sensors and TENG devices in running monitoring.

Giant permittivity response and enhanced nonlinear electrical properties in a novel perovskite-like ceramic with multiple elements

Copper calcium titanate (CaCu3Ti4O12, CCTO) ceramics are receiving a great deal of attention for advanced electronic and energy storage device applications owing to their giant permittivity response and good temperature stability. However, the development and real applications of CCTO ceramics are generally restricted by their large dielectric loss and low breakdown electric field strength. In the present study, a novel type of perovskite-like Na1/3(Ca1/2Sr1/2)1/3(Bi1/2Y1/2)1/3Cu3Ti4O12 (NCSBYCTO) ceramics were designed via multiple elements strategy based on the high-entropy concept. Consequently, all the NCSBYCTO ceramics present a giant permittivity response (103∼104), good stability of temperature and frequency, and remarkable relaxation characteristics, especially the NCSBYCTO ceramic sintered at 1050 °C exhibits a relative balance between the giant permittivity of about 7.0 × 103–9.5 × 103 and the lower dielectric loss of approximately 0.043–0.294 at a frequency range of 104–106 Hz under room temperature. Furthermore, all the NCSBYCTO ceramics present an obvious nonlinear characteristic. More encouragingly, a higher breakdown field strength of around 2552.56 V/cm accompanied by a larger nonlinear coefficient of about 6.48 is achieved in the NCSBYCTO ceramic sintered at 1070 °C. A significant electrical heterogeneity structure and electron defect structure induced by the existence of mixed-valence Cu+/Cu2+ and Ti3+/Ti4+ are also found in the NCSBYCTO ceramics. The giant permittivity response, low dielectric loss and improved nonlinear properties can be considered the synergistic effect of the defect mechanism and the internal barrier layer capacitor model. This finding offers a route for designing giant permittivity ceramics with brilliant dielectric properties and nonlinear behaviors, which is expected to benefit dual-functional device applications of capacitors and varistors.

A low-cost, portable, dual-function readout device for amplification-based point-of-need diagnostics.

The first critical step in timely disease management is rapid disease identification, which is ideally on-site detection. Of all the technologies available for disease identification, nucleic acid amplification-based diagnostics are often used due to their specificity, sensitivity, adaptability, and speed. However, the modules to interpret amplification results rapidly, reliably, and easily in resource-limited settings at point-of-need (PON) are in high demand. Therefore, we developed a portable, low-cost, and easy-to-perform device that can be used for amplification readout at PON to enable rapid yet reliable disease identification by users with minimal training.

A dual-function tunable terahertz multiband bandpass filter based on PET woven-wire meshes with conductive coating surfaces

A multifunctional terahertz (THz) device with frequency tunability, amplitude modulation and spectral filtering abilities, and substrate flexibility is highly desired for various applications, such as THz communication, sensing, wearable optoelectronics. Therefore, this study proposed a 3D artificial material based on a flexible polyethylene terephthalate (PET) woven-wire mesh with conductive coating surfaces. This material was conceptually demonstrated in experiments as a dual-functional THz device. In addition, the transmission properties of this artificial material were experimentally and numerically explored with reasonable agreement. Then, the underlying mechanism of the spectral characteristics was qualitatively elucidated. The amplitudes and frequencies of the spectral characteristics were successfully validated to be passively manipulated by tailoring the structural parameters of a unit cell and changing the surface conductivities of a device. This process opened the application feasibility of a frequency tunable bandpass filter and a power switch at the THz regime. For the bandpass filter application, the tri-frequency modulation capability was experimentally demonstrated, and a frequency tuning bandwidth of 0.249 THz was achieved by varying the conductivity of the device’s surface-coating layer from 0.44 to 77 MS/m. For the power switch application, the largest modulation depth between the on and off states of a device was successfully demonstrated at approximately 21.3 dB at 0.271 THz. This dual-function THz device has the advantages of compactness, low cost, and easy fabrication, thus providing an alternative strategy to develop tunable, flexible, and versatile THz devices for broad applications.

Dual-Functional Electrochromic Smart Window Using WO3·H2O-rGO Nanocomposite Ink Spray-Coated on a Low-Cost Hybrid Electrode.

Electrochromic windows have gained growing interest for their ability to change their optical state in the visible and NIR ranges with minimal input power, making them energy-efficient. However, material processing costs, fabrication complexity, and poor electrochromic properties can be barriers to the widespread adoption of this technology. To address these issues, electrochromic material and fabrication processes are designed to realize their potential as a cost-effective and energy-efficient technology. In this work, an electrochromic composite material-based ink is synthesized consisting of WO3·H2O nanoplates supported on rGO (reduced graphene oxide) nanosheets (WH-rGO), wherein an optimized amount of rGO (0.05 to 0.5 wt %) is introduced for providing a higher conduction pathway for efficient charge transport without sacrificing the electrochromic performance of WO3·H2O nanoplates. The stable ink dispersion prepared in the study is deposited by spray coating on transparent conducting electrodes over large areas (25 cm2). The WH-rGO nanocomposite (0.4 wt %) results in 43% optical modulation at 700 nm, with bleaching and coloration times of 6 and 8 s, respectively. Interestingly, the device also possesses an electrochemical energy storage capability with an areal capacitance of 16.3 mF/cm2. The electrochromic composite material is successfully translated on tin doped indium oxide (ITO)-coated Al metal mesh hybrid electrodes (T = 80%, Rs = 40 Ω/□) to replace ITO. Finally, an electrochromic device of 5 × 5 cm2 is fabricated by spray-coating the ink on cost-effective ITO/Al-mesh hybrid electrodes. The device displays blue to colorless modulation with an excellent bleaching time of 0.43 s and a coloration time of 2.16 s, making it one among the fast-operating devices fabricated by complete solution processing. This work showcases the economical production of a dual-function electrochromic device, which can be a feasible option as an alternative to existing ITO-based devices in both automotive and infrastructure applications.

Self-Powering Sensory Device with Multi-Spectrum Image Realization for Smart Indoor Environments.

The development of organic-based optoelectronic technologies for the indoor Internet of Things market, which relies on ambient energy sources, has increased, with organic photovoltaics (OPVs) and photodetectors (OPDs) considered promising candidates for sustainable indoor electronic devices. However, the manufacturing processes of standalone OPVs and OPDs can be complex and costly, resulting in high production costs and limited scalability, thus limiting their use in a wide range of indoor applications. This study uses a multi-component photoactive structure to develop a self-powering dual-functional sensory device with effective energy harvesting and sensing capabilities. The optimized device demonstrates improved free-charge generation yield by quantifying charge carrier dynamics, with a high output power density of over 81 and 76 µW cm-2 for rigid and flexible OPVs under indoor conditions (LED 1000lx (5200 K)). Furthermore, a single-pixel image sensor is demonstrated as a feasible prototype for practical indoor operating in commercial settings by leveraging the excellent OPD performance with a linear dynamic range of over 130dB in photovoltaic mode (no external bias). This apparatus with high-performance OPV-OPD characteristics provides a roadmap for further exploration of the potential, which can lead to synergistic effects for practical multifunctional applications in the real world by their mutual relevance.

Dual-functional electrochromic supercapacitors with electrospun TiO2 ion storage layer

We have developed dual-functional electrochromic supercapacitors (ECSs) incorporating electrospun TiO2 nanofibers as an ion storage layer (ISL). The prepared ISL-ECSs exhibit excellent integrated electrochromic performances at low driving voltages due to high visible transparency and energy storage capabilities. This study describes direct electrospinning TiO2 on an FTO electrode and fabricating asymmetric electrochromic devices with viologen-based ion gel compositions. The electrospinning technique proved suitable for producing oxide nanostructures that facilitate efficient ion transport. The surface morphology of the fabricated nanoweb was analyzed using SEM and AFM images. The electrochromic performances were evaluated through cyclic voltammetry and spectroelectrochemical measurements, and charge storage properties were examined by galvanostatic charge–discharge curves. The optimized dual-functional devices demonstrated a large transmittance contrast of up to 87 %, high coloration efficiency of 175.7 cm2/C, areal capacitance of 20.53 mF/cm2, and good charging-discharging cyclic stability. Furthermore, the practical feasibility of the ISL-ECSs was demonstrated by evaluating their ability to serve as a power source for illuminating an LED lamp. The findings suggest the potential application of ISL-ECSs for dual-functional smart windows, in which the color intensity visualizes the real-time energy storage status.