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The increasing demand for advanced transparent and flexible display technologies has led to significant research in thin-film transistors (TFTs) with high mobility, transparency, and mechanical robustness. In this study, we fabricated all-transparent TFTs (AT-TFTs) utilizing amorphous indium-zinc-tin-oxide (a-IZTO) as a dual-functional material for both the channel layer and transparent conductive electrodes (TCEs). The a-IZTO was deposited using radio-frequency magnetron sputtering, with its composition adjusted for both channel and electrode functionality. XRD analysis confirmed the amorphous nature of the a-IZTO layers, ensuring structural stability post-thermal annealing. The a-IZTO TCEs demonstrated high optical transparency (89.57% in the visible range) and excellent flexibility, maintaining a low sheet resistance with minimal degradation even after 100,000 bending cycles. The fabricated AT-TFTs exhibit superior field-effect mobility (30.12 cm2/V·s), an on/off current ratio exceeding 108, and a subthreshold swing of 0.36 V/dec. The AT-TFT device demonstrated a minimum transmittance of 75.46% in the visible light range, confirming its suitability for next-generation flexible and transparent displays. [ABSTRACT FROM AUTHOR]

Perovskite materials such as organic‐inorganic MAPbX3 (X = Cl, I, Br) have attracted broad interests in photoelectric applications, such as image sensors and photovoltaics. Here, a facile and general approach, called soft‐print solvent‐assisted evaporation crystallization (SSEC) is reported, for fabrication of highly crystallized, air‐stable, and flexible perovskite micromesh films, including organic–inorganic (MAPbX3) and inorganic (CsPbX3) perovskite. Scanning and transmission electron microscopy (SEM/TEM) characterization reveals their high crystallinity without obvious grain boundaries. The photodetectors constructed based on MAPbI3 micromesh films exhibit a typical responsivity of ≈352 A W−1 and detectivity of ≈5.7 × 1013 Jones (at 650 nm in wavelength). The MAPbI3 micromesh film also shows good mechanical stability when bended at different bending radius, and after 800 bending cycles, they still exhibit highly reproducible photocurrent and on/off switching ratios. Furthermore, they are also air‐stable that they can survive for >20 days in high humid environments (65–75%) with <10% reduction in photocurrent. This work provides a facile and scalable approach for fabrication of highly crystallized, stable, and flexible perovskite micromesh films for a variety of optoelectronic applications with improved performance and durability. [ABSTRACT FROM AUTHOR]

It is significant to explore the electrode materials for supercapacitors with high storage energy and long cycling stability. Herein, nanoporous Ni‐Co3O4@CoMoO4 composite is fabricated with excellent electrochemical performance. The as‐prepared sample delivers a specific capacity of 1212 C g−1 at 1 A g−1 and superior cycle performance (91.7% after 10 000 times charging and discharging). Several asymmetric supercapacitors (ASCs) are assembled using the synthesized products as cathode. They achieve an energy density of 102 Wh kg−1 at a power density of 2770 W kg−1. In addition, the devices present outstanding mechanical stability after multiple bending, demonstrating their potential application in the field of portable energy storage devices. [ABSTRACT FROM AUTHOR]

Due to the atomic thickness of 2D MoS2 film, the electronic structure is easily tunable by electric field and exhibits abundant property. However, due to the limit capacitance of inorganic dielectric, the tunability is still not well exhibited. Herein, a MoS2 phototransistor with large tunability driven by ion‐gel film is fabricated. To improve the interface and reduce the dark current, the passivation layer is used to hinder the leakage current. With the passivation layer, there will be a specific barrier height on the interface of metal electrodes and ion‐gel membrane. Under effect of the PVA (polyvinyl alcohol) passivation layer, the current on/off radio can reach 107 and the mobility can reach 6.54 cm2/(Vs) superior to the one without passivation layer. There is an abnormal behavior in the transistor including positive and negative photoresponse due to the coupling of the photogating effect and the adsorption of negative ion. The photoresponsivity can increase by 29 times which can reach 603.48 A W−1 at 400 nm illumination. Furthermore, the flexible transistor based on ion‐gel can be demonstrated and it found that the transistor still has a considerable photoresponse with strain of 0.49%. This work provides a new solution for flexible wearable electronic and photoelectronic detection field. [ABSTRACT FROM AUTHOR]

Flexible light‐emitting devices have attracted attention as a novel bio‐interface connecting living tissues with electronics due to their high brightness, low power consumption, and durability in humid environments. Introduction of vertically current‐injected micro‐light‐emitting diodes (MicroLEDs) into this film can enhance the MicroLED effective area and improve device characteristics. In this study, the MicroLED transfer technology onto conductive materials is investigated. The feasibility of batch transferring MicroLEDs onto a conductive polymer is demonstrated by PEDOT:PSS layer. For non‐Ohmic characteristics between n‐GaN and PEDOT:PSS, a backside‐open MicroLED hollow structure is proposed, enabling the formation of Ti/Au electrodes on the backside of MicroLED. By transferring the fabricated vertically current‐injected MicroLEDs onto the PEDOT:PSS layer, a flexible vertically current‐injected LED film is achieved, observing uniform blue light emission. The developed MicroLED film holds promise as a new neuroscience tool for targeting specific areas of the brain with light. [ABSTRACT FROM AUTHOR]

Flexible MicroLEDs hold great promise as a novel tool for advancing optogenetics, enabling applications in biology. Such applications require the technology to assemble MicroLEDs onto ultra‐thin biocompatible films that conform to the delicate and uneven brain and biological tissues. In this study, a batch transfer technique using thermal release sheets is propsed. By optimizing the gate structures that support the hollow structure, a method to transfer MicroLEDs to the film without causing damage is established. It is successfully demonstrated that the flexible MicroLED films, fabricated using this technique, can be placed on the brain surface of transgenic mice and induce neural activity through optogenetic stimulation. [ABSTRACT FROM AUTHOR]

Mica is a promising substrate for flexible photonic applications because it can be fabricated using wafer‐scale multiple exfoliations. However, the large lattice mismatch between mica and III‐nitrides hinders their application in III‐nitride semiconductor devices. In this study, two types of light‐emitting diode (LED) epilayers, blue and green, are epitaxially fabricated on 2‐inch exfoliated mica substrates using sputtered AlN as a buffer layer to address the lattice mismatch. The LED epilayers on mica substrate exhibit excellent single‐crystalline quality with a low threading dislocation density of 2.07 × 109 cm−2 in the GaN region and smooth surface morphology with a root mean square (RMS) roughness of 0.58 nm in a 5 × 5 µm2 scanned area, demonstrating that mica is an excellent platform for III‐nitride semiconductors. Moreover, the structures are reproduced stably on multiple exfoliated mica at the wafer scale, which verified the reusability and reproducibility of III‐nitride/mica in terms of crystallinity, surface morphology, and transparency. Strong electroluminescence of the LED epilayers confirmed the potential of mica in electrically driven flexible opto‐electronics. Therefore, this results demonstrated the potential of mica substrates in III‐nitride semiconductors and provide a novel pathway for revolutionizing the fabrication of III‐nitride‐based flexible devices. [ABSTRACT FROM AUTHOR]

Hydrogel electrolytes are an integral part of flexible solid-state supercapacitors. To further improve the low ionic conductivity, large interfacial resistance and poor cycling stability for hydrogel electrolytes, the V4C3Tx MXene-enhanced polyvinyl alcohol hydrogel electrolyte was fabricated to enhance its mechanical and electrochemical performance. The high-conductivity V4C3Tx MXene (16,465.3 S m−1) bonding transport network was embedded into the PVA-H2SO4 hydrogel electrolyte (PVA- H2SO4-V4C3Tx MXene). Results indicate that compared to the pure PVA-H2SO4 hydrogel electrolyte (105.3 mS cm−1, 48.4%@2,800 cycles), the optimal PVA-H2SO4-V4C3Tx MXene hydrogel electrolyte demonstrates high ionic conductivity (133.3 mS cm−1) and commendable long-cycle stability for the flexible solid-state supercapacitors (99.4%@5,500 cycles), as well as favorable mechanical flexibility and self-healing capability. Besides, the electrode of the flexible solid-state supercapacitor with the optimal PVA-H2SO4-V4C3Tx MXene hydrogel as the solid-state electrolyte has a capacitance of 370 F g−1 with almost no degradation in capacitance even under bending from 0° to 180°. The corresponding energy density for flexible device is 4.6 Wh kg−1, which is twice for that of PVA-H2SO4 hydrogel as the solid-state electrolyte. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA)-based hydrogels have attracted significant attention due to their excellent biocompatibility, tunable mechanical properties, and ability to form stable three-dimensional networks. This comprehensive review explores the recent advancements in PVA-based hydrogels, focusing on their unique properties, fabrication strategies, and multifunctional applications. Firstly, it discusses various facile synthesis techniques, including freeze/thaw cycles, chemical cross-linking, and enhancement strategies, which have led to enhanced mechanical strength, elasticity, and responsiveness to external stimuli. These improvements have expanded the applicability of PVA-based hydrogels in critical areas such as biomedical, environmental treatment, flexible electronics, civil engineering, as well as other emerging applications. Additionally, the integration of smart functionalities, such as self-healing capabilities and multi-responsiveness, is also examined. Despite progress, challenges remain, including optimizing mechanical stability under varying conditions and addressing potential toxicity of chemical cross-linkers. The review concludes by outlining future perspectives, emphasizing the potential of PVA-based hydrogels in emerging fields like regenerative medicine, environmental sustainability, and advanced manufacturing. It underscores the importance of interdisciplinary collaboration in realizing the full potential of these versatile materials to address pressing societal challenges. [ABSTRACT FROM AUTHOR]

Transition metal disulfide compounds (TMDCs) emerges as the promising candidate for new‐generation flexible (opto‐)electronic device fabrication. However, the harsh growth condition of TMDCs results in the necessity of using hard dielectric substrates, and thus the additional transfer process is essential but still challenging. Here, an efficient strategy for preparation and easy separation‐transfer of high‐uniform and quality‐enhanced MoS2 via the precursor pre‐annealing on the designed graphene inserting layer is demonstrated. Based on the novel strategy, it achieves the intact separation and transfer of a 2‐inch MoS2 array onto the flexible resin. It reveals that the graphene inserting layer not only enhances MoS2 quality but also decreases interfacial adhesion for easy separation‐transfer, which achieves a high yield of ≈99.83%. The theoretical calculations show that the chemical bonding formation at the growth interface has been eliminated by graphene. The separable graphene serves as a photocarrier transportation channel, making a largely enhanced responsivity up to 6.86 mA W−1, and the photodetector array also qualifies for imaging featured with high contrast. The flexible device exhibits high bending stability, which preserves almost 100% of initial performance after 5000 cycles. The proposed novel TMDCs growth and separation‐transfer strategy lightens their significance for advances in curved and wearable (opto‐)electronic applications. [ABSTRACT FROM AUTHOR]

Flexible electrochemical sensors can adhere to any bendable surface with conformal contact, enabling continuous data monitoring without compromising the surface's dynamics. Among various materials that have been explored for flexible electronics, metal–organic frameworks (MOFs) exhibit dynamic responses to physical and chemical signals, offering new opportunities for flexible electrochemical sensing technologies. This review aims to explore the role of electrocatalysis in MOF films specifically designed for flexible electrochemical sensing applications, with a focus on their design, fabrication techniques, and applications. We systematically categorize the design and fabrication techniques used in preparing MOF films, including in situ growth, layer-by-layer assembly, and polymer-assisted strategies. The implications of MOF-based flexible electrochemical sensors are examined in the context of wearable devices, environmental monitoring, and healthcare diagnostics. Future research is anticipated to shift from traditional microcrystalline powder synthesis to MOF thin-film deposition, which is expected to not only enhance the performance of MOFs in flexible electronics but also improve sensing efficiency and reliability, paving the way for more robust and versatile sensor technologies. [ABSTRACT FROM AUTHOR]

Flexible inorganic electroluminescent devices exhibit high luminous efficiency, rapid response, low production costs and stable luminescence. These devices can be employed for flexible displays, intelligent sensing and other functions, making them promising candidates for applications in smartphones, electronic skin and smart wearables. Textile materials, with their flexibility, wearability, and well-established processing techniques, serve as excellent substrates for these flexible electroluminescent devices. In recent years, the structural design of flexible inorganic electroluminescent devices has matured significantly, driving research and development efforts across a wide range of applications, particularly in wearable electronics, displays and bionic robots. Electroluminescence primarily arises when a current passes through a substance, causing it to emit light under a strong electric field. Two main types of electroluminescence exist: injection electroluminescence and intrinsic electroluminescence. In the case of injection electroluminescence (also known as low-field electroluminescence), electrons and holes are directly injected from the electrodes into the crystal. When these charge carriers recombine within the crystal, excess energy is released in the form of light. Intrinsic electroluminescence (or high-field electroluminescence) is akin to an in vivo luminescence effect. In inorganic electroluminescent materials, electrons gain energy and collide with and excite luminescent centers under high electric fields. Consequently, the excited electrons in the luminescent centers transition to lower energy states, emitting light. Currently, the most widely used inorganic electroluminescent materials included zinc sulfide-based compounds and perovskite materials. Zinc sulfide exhibits excellent thermal stability, mechanical strength and high carrier mobility, making it a common choice for thin-film transistors and other electronic devices. Doping zinc sulfide with metal elements (such as copper, aluminum or manganese) allows for the creation of different variants, such as zinc sulfide: copper (green) and zinc sulfide: manganese (orange), enabling tunable emission colors by adjusting the frequency of the AC electric field. However, localized electric field breakdown remains a challenge, leading to device damage. Perovskite materials offer adjustable band gaps, narrow half-peak widths, high carrier mobility and efficient fluorescence. When used as the light- emitting layer in perovskite light-emitting diodes, they exhibit high color purity, brightness and a wide color gamut. By modifying the composition of halide ions and adjusting cation proportions, the optical and electrical properties of perovskite can be tailored, showing promise in lighting and display applications. Nevertheless, challenges related to stability, mechanical properties, toxicity, and large-scale manufacturing persist for flexible perovskite electroluminescent materials As demand grows for convenient solutions, electroluminescent devices are expected to serve additional functions, including health monitoring, electronic communication and aerospace applications. Among these, textile displays play a crucial role in transmitting information anytime and anywhere. Wearable electronic products integrated into shoes, clothing and watches enhance human convenience. The acquisition and display of textile electroluminescent devices rely on luminous fabrics and fibers, utilizing printing, coating, lamination and fiber weaving technologies. These methods impose stringent requirements on brightness and device lifespan, necessitating improved device structures and combination modes to achieve stable and durable performance in textile applications. At present, large-scale continuous production of flexible inorganic electroluminescent devices remains a challenge. As new display applications emerge, stricter demands are placed on flexible electroluminescent devices. In flexible inorganic electroluminescent devices, the development and application of electroluminescent devices need to be combined with other disciplines to develop a multifunctional device to meet people's needs. [ABSTRACT FROM AUTHOR]

The red V2O5 sol was prepared by facile alternating stirring and ultrasonic dispersion route. A V2O5 film fabricated on ITO-PET by electrophoresis method was used to demonstrate a flexible electrochromic device. The effects of applied voltage and electrophoresis time for V2O5films were investigated in detail. When the electrophoresis time was kept 30 s, the applied voltage was above 3 V to deposit uniform V2O5-PET film. The electrophoresis time could more significantly regulate the deposition of V2O5 on ITO-PET film. A flexible electrochromic device with "sandwich" structure was fabricated using V2O5 film, and its electrochromic performance of the device was evaluated. The flexible V2O5 electrochromic devices show the multicolor electrochromic performance of yellow, yellow-green, green and orange-red. The coloration efficiency values of V2O5 devices were 21.6 cm2C − 1 (from initial yellow to green) and 26.9 cm2C − 1 (from green to orange-red), respectively, and the highest transmittance modulation range was 51% at 741 nm. The work provided a facile and green method for fabrication of flexible V2O5 electrochromic device. [ABSTRACT FROM AUTHOR]

This work presents the synthesis of para-quinone methides (p-QMs), which were deposited as films using the high vacuum sublimation technique after being chemically characterized. The p-QMs films were characterized morphologically and structurally using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. In addition, their optical behavior was studied by means of ultraviolet–visible spectroscopy, and the optical gaps obtained were in the range of 2.21–2.71 eV for indirect transitions, indicating the semiconductor behavior of the p-QMs. The above was verified through the manufacture and evaluation of the electrical behavior of rigid semiconductor devices, in which fluorine-doped tin oxide-coated glass slides (FTO) were used as an anode and substrate. Finally, as an original, ecological, and low-cost application, the FTO was replaced by substrates and anodes made from recycled Tetra Pak®, generating flexible semiconductor devices. Although the electrical current transported depends on the type of p-QMs, the substituent in its structure, and the morphology, the kinds of substrate and anode also influence the type of electrical behavior of the device. This current–voltage study demonstrates that p-QM2 with 4-Cl-Ph as a radical, p-QM3 with 4-Et2N-Ph as a radical, and p-QM6 with 5-(1,3-benzodioxol) as a radical can be used in optoelectronics as semiconductor films. [ABSTRACT FROM AUTHOR]

Converting non‐visual light into photocurrent while maintaining high visual transparency is vital for semitransparent organic solar cells (ST‐OSCs) application, yet often challenging over insufficient invisible light‐harvesting. Herein, spectrally selective optical manipulation for ST‐OSCs with high visual light transparency and full‐spectral non‐visual light reflection is proposed by matching the optical admittance of ultrathin Ag films using ZnS and MgF2. The reflection of optically enhanced ST‐OSCs at the spectral region beyond the human eye's response spectrum is improved and the transmission in the visual region is simultaneously enhanced. By further integrating an anti‐reflective structure, the optimal structure boosts the average visible transmittance and power conversion efficiency of ST‐OSCs to 44.3% and 12.6%, respectively, yielding a record light utilization efficiency of 5.6%. Corresponding flexible ST‐OSCs with high mechanical stability implies that this work provides a facile and universal strategy for ST‐OSCs aiming at building integrated photovoltaics. [ABSTRACT FROM AUTHOR]

Transmembrane transport analysis is essential for understanding cell physiological processes. Based on an artificial simulation of internal and external cellular environment, this paper introduces an innovative approach to investigate the microscopic behavior of small molecules through porin protein under mechanical curvature of lipid membrane. A flexible device system is developed, enabling quantitative electronic transmembrane analysis. The key transistor comprises a flexible, microporous electrode covered with the support lipid bilayers (SLBs) to mimic artificial cellular membrane, serving as an extended gate of the field‐effect transistor (FET). The transmembrane behaviors of charged ions and small molecules can be effectively monitored in real time by this FET‐based flexible device system. The flexibility of the electrode allows analyzing the transmembrane behavior under different mechanical bends. In this study, the developed flexible device is employed for the first time to simulate the mechanical bending of cellular membrane embedded with channel proteins and to monitor the transmembrane behavior of small molecules, thus providing a more authentic representation of membrane protein at a curved state. This approach holds the potential to contribute as a platform‐based technological advancement, supporting research into toxicological mechanisms and facilitating drug screening endeavors. [ABSTRACT FROM AUTHOR]

Abstract Mica is a promising substrate for flexible photonic applications because it can be fabricated using wafer‐scale multiple exfoliations. However, the large lattice mismatch between mica and III‐nitrides hinders their application in III‐nitride semiconductor devices. In this study, two types of light‐emitting diode (LED) epilayers, blue and green, are epitaxially fabricated on 2‐inch exfoliated mica substrates using sputtered AlN as a buffer layer to address the lattice mismatch. The LED epilayers on mica substrate exhibit excellent single‐crystalline quality with a low threading dislocation density of 2.07 × 109 cm−2 in the GaN region and smooth surface morphology with a root mean square (RMS) roughness of 0.58 nm in a 5 × 5 µm2 scanned area, demonstrating that mica is an excellent platform for III‐nitride semiconductors. Moreover, the structures are reproduced stably on multiple exfoliated mica at the wafer scale, which verified the reusability and reproducibility of III‐nitride/mica in terms of crystallinity, surface morphology, and transparency. Strong electroluminescence of the LED epilayers confirmed the potential of mica in electrically driven flexible opto‐electronics. Therefore, this results demonstrated the potential of mica substrates in III‐nitride semiconductors and provide a novel pathway for revolutionizing the fabrication of III‐nitride‐based flexible devices.

Abstract Detection of liquid viscosity is important from chemical engineering to daily safety. To match the emergence of internet of things, precise and fast viscosity determination is attracting intention in the society. However, most miniature viscometers face limitations such as high operation frequency, moving component, and non‐linear sensing, etc. Herein, a flexible viscometer is developed via coupling the electromagnetic induction with inherent oscillation of a magnetized oscillator. The mechanism allows vibration of the oscillator to be electrically reflected using damping signals. By analyzing the damping factor from viscosity‐dependent voltage profiles, viscosity of an unknown liquid can be accurately obtained. Furthermore, the 3D structures is developed with a dual‐template method, which enables convenient and high‐throughput preparations of devices with complex 3D structures. Via optimizing the structural and physical parameters, the “sphere” oscillator enables a linear relationship between the damping factor and the square root of viscosity for quantitative sensing in range of 0.01809–24.7 mPa s. The principle of electromagnetic induction renders the viscometer with superiorities of low operating frequency, remote sensing, self‐powered and chemical stability. It is expected that the methodology and damping dominant mechanism will serve as a promising platform for cost‐effective, portable and convenient viscosity detection for applications in diverse fluids.

This work presents the evaluation of the electrical behavior of a flexible photoconductor with a planar heterojunction architecture made up of organic semiconductor films deposited by high vacuum evaporation. The heterojunction was characterized in its morphology and mechanical properties by scanning electron microscopy and atomic force microscopy. The electrical characterization was carried out through the approximations of ohmic and SCLC (Space-Charge Limited Current) behaviors using experimental J–V (current density–voltage) curves at different voltages and under different light conditions. The optimization of the photoconductor was carried out through annealing and accelerated lighting processes. With these treatments, the Knoop Hardness of the flexible photoconductor has reached a value of 8 with a tensile strength of 5.7 MPa. The ohmic and SCLC approximations demonstrate that the unannealed device has an ohmic behavior, whereas the annealed device has an SCLC behavior, and after the optimization process, an ohmic behavior and a maximum current density of 0.34 mA/mm2 were obtained under blue light. The approximations of the device's electron mobility ( μ n ) and free carrier density ( n 0 ) were performed under different light conditions, and the electrical activation energy and electrical gap were obtained for the flexible organic device, resulting in appropriate properties for these applications. [ABSTRACT FROM AUTHOR]

Binary metal oxide materials, such as nickel oxide, are widely used in flexible resistive variable memory devices due to advantages such as their easily controllable material composition, simple structural composition, and good compatibility between manufacturing processes and complementary metal oxide processes. In this work, a solution combustion method was employed to prepare NiOx thin films for use as a resistive switching layer of resistance random-access memory. The formation temperature of the NiOx layer in the RRAM device was kept as low as 175 °C, making the device compatible with flexible substrates. With polyethylene naphthalenediate as the substrate, the NiOx-based RRAM exhibited obvious bipolar resistance-switching properties, superb bending resistance, and good stability. Through theoretical fitting and structural characterization, the conduction mechanisms were attributed to the combination of the space-charge-limited current and Ohmic mechanisms, while the valence change mechanism was determined to be the resistive switching mechanism. This study demonstrates a low-temperature and scalable approach to constructing NiOx-based RRAM devices on flexible substrates. [ABSTRACT FROM AUTHOR]

Abstract Transmembrane transport analysis is essential for understanding cell physiological processes. Based on an artificial simulation of internal and external cellular environment, this paper introduces an innovative approach to investigate the microscopic behavior of small molecules through porin protein under mechanical curvature of lipid membrane. A flexible device system is developed, enabling quantitative electronic transmembrane analysis. The key transistor comprises a flexible, microporous electrode covered with the support lipid bilayers (SLBs) to mimic artificial cellular membrane, serving as an extended gate of the field‐effect transistor (FET). The transmembrane behaviors of charged ions and small molecules can be effectively monitored in real time by this FET‐based flexible device system. The flexibility of the electrode allows analyzing the transmembrane behavior under different mechanical bends. In this study, the developed flexible device is employed for the first time to simulate the mechanical bending of cellular membrane embedded with channel proteins and to monitor the transmembrane behavior of small molecules, thus providing a more authentic representation of membrane protein at a curved state. This approach holds the potential to contribute as a platform‐based technological advancement, supporting research into toxicological mechanisms and facilitating drug screening endeavors.

In this study, we fabricated a coplanar waveguide using a novel graphene-silver nanowire composite structure (GNCS) on a polyethylene terephthalate (PET) substrate and then investigated its radio frequency (RF) characteristics. According to the measured results, the coplanar waveguide employing GNCS exhibited a substantially lower loss of transmission line than conventional waveguides. Furthermore, compared to the conventional graphene-based coplanar waveguide, the proposed structure allowed for lower skin depth and higher conductivity, resulting from the high electric conductivity of the silver nanowire. In addition, repetitive bending tests, which were performed to investigate the electric stability of the graphene-silver nanowire, showed that the coplanar waveguide employing GNCS offered substantially better electrical stability than the conventional graphene-based coplanar waveguide. These results indicate that the graphene-silver nanowire structure is a promising candidate for application in flexible wireless communication systems. Notably, this is also the first study to investigate the RF performance and electrical stability of a graphene-silver nanowire/PET structure.

The rapid development of portable and wearable electronic devices is responding to the urgent demand for high-efficiency flexible energy storage devices. Flexible supercapacitors, showing long cycle life, high power density, and good safety, are considered ideal candidates. Nevertheless, the relatively low energy density restricts their practical applications. With a large dielectric constant of 18–46, Ta2O5-based materials typically exhibit excellent electron-binding ability, which is critical for enhancing the energy density of supercapacitors. In this work, the free-standing β-Ta2O5/single-walled carbon nanotubes (SWCNTs) composite film was prepared, with a high β-Ta2O5 loading of over 70%. By anchoring β-Ta2O5 nanoparticles onto the surface of SWCNTs, the system's flexibility and conductivity were significantly enhanced, which also facilitated the intercalation electrodynamics of metal cations. As a result, the flexible β-Ta2O5/SWCNTs film exhibits excellent Li-ion storage performance, with a high volumetric specific capacitance of 392.3 F cm−3 at the scan rate of 10 mV s−1 and 198.9 F cm−3 at 500 mV s−1. In addition, the asymmetric device, assembled by the β-Ta2O5/SWCNTs and activated carbon films, shows a high energy density of 45.5 Wh kg−1 at the power density of 10.8 kW kg−1. This technique opens up a new avenue for improving the energy density and rate performance of flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Spatiotemporally controlled chemical delivery is crucial for various biomedical engineering applications. Here, a novel concept of electrically controllable delivery utilizing electroosmotic flow (EOF) generated in a combination of anionic and cationic hydrogels (A‐ and C‐hydrogels) is reported. The unique advantages of the A/C‐hydrogel combination are demonstrated utilizing a flexible sheet‐shaped and a thin tubular devices. Since the directions of EOF in the A‐ and C‐hydrogels are opposite to each other, the ionic current for EOF generation flows inside the delivery devices, enabling chemical delivery without accompanying external ionic current that could stimulate target cells and tissues. A thin tubular device, which can be inserted into narrow in vivo structures and be integrated with other flexible devices, exhibits high robustness and repeatability thanks to the flexibility and water retentivity of hydrogels. The EOF devices with A/C‐hydrogels combination show high controllability superior to the pumping with a conventional syringe; the volumetric flow rate is able to be controlled proportionally to the current applied, for example, ≈0.4 µL (mA min)−1 for the tubular device. The developed EOF‐based devices are versatile for delivery of most chemicals regardless of their charge and size, and have great potential for both biomedical researches and therapeutics. [ABSTRACT FROM AUTHOR]

This paper proposes a flexible vibrotactile actuator based on a dielectric elastomer which is fabricated by mixing a PDMS-Ecoflex elastomer and PC (propylene carbonate) solution. The proposed flexible vibrotactile actuator is composed of a top electrode, an adhesive tape, the PDMS-Ecoflex-PC-based elastomer, and a bottom electrode. The applied electric field between two parallel electrodes (top and bottom electrodes) creates an electrostatic force in the actuator, resulting in the actuator being compressed. The performance of the vibrotactile actuator based on dielectric elastomers is affected by the mechanical and dielectric properties of the dielectric elastomer. So, in this paper, we experimentally optimize the design of the haptic actuator and then quantitatively evaluate the actuator. For evaluation, the six samples of PDMS-Ecoflex-PC elastomers having different mixing ratios are prepared and their material properties are investigated by experiments. We fabricate the haptic actuators based on PDMS-Ecoflex-PC elastomers and then measure the haptic behaviors of the proposed actuator as a function of the applied voltage amplitude and frequency. Furthermore, we inquire the response time of the proposed actuator. Maximum vibrational force of the optimized sample is about 0.556 N at 140 Hz which is strong enough to stimulate human finger, and the response time is 21 ms which is fast enough to obtain the touch feedback in real time. From the results, we show that the proposed vibrotactile actuator creates a variety of haptic sensations in real time. [ABSTRACT FROM AUTHOR]

A pulsed laser annealing method is utilized to directly synthesize nickel silicide (NiSi) as a contact material to improve the contact of electric devices. Three laser wavelengths, 355 nm (ultraviolet laser), 532 nm (green laser), and 1064 nm (infrared laser), are used for the NiSi synthesis during the pulsed laser annealing process. A NiSi phase with low sheet resistance is formed by an ultraviolet laser annealing (ULA) process without damaging the polyimide (PI) substrate. With the integration of the ULA process‐induced NiSi into p‐nnel MOSFET (PMOS) and n‐channel MOSFET (NMOS) devices, the on/off ratio improves significantly, and the field‐effect mobility increases by 30% because of the reduction in contact resistance from 21 to 8.5 kΩ. In addition to the PMOS and NMOS, the gains of the CMOS inverter at different Vdd values are improved by at least 30%. Moreover, the static noise margin of 6T‐SRAM is elevated from 0.82 to 1 V at Vdd = 4 V. The ability of the ULA process to synthesize a high‐quality NiSi layer on a flexible substrate is demonstrated. The integration of NiSi into electrical devices offers a new pathway for improving the electrical behavior of flexible devices. [ABSTRACT FROM AUTHOR]

Colloidal quantum dot (CQD) lasers show promising applications in flexible optoelectronic devices, due to their tunable emission wavelength, narrow spectrum bandwidth and high power intensity. However, fabricating a flexible CQD laser is challenging because of the difficulties in fabricating optical cavities on flexible substrates using traditional microfabrication technologies. Herein, we propose a one-step self-assembly approach to fabricate flexible CQD supraparticle lasers. The whole assembly approach is processed in a liquid environment without surfactants, and the formed spherical CQD supraparticles are featured with smooth surfaces, serving as high-quality-factor whispering-gallery mode cavities to support laser oscillation. A low lasing threshold of 54 µJ/cm2 is observed while exciting a CQD supraparticle with pulsed femtosecond lasers. The calculated cavity quality factor of 963 for CQD supraparticle lasers is twofold larger than that of CQD lasers assembled with surfactants. Moreover, the CQD supraparticles can serve as free-standing lasers, which allows them to be deposited on flexible substrates such as paper and cloth. Furthermore, our CQD lasers show high stability, after being continuously photoexcited above the threshold for 400 min, their lasing intensity remains at 85.7% of the initial value. As bright, free-standing and long-term stable light sources, the assembled CQD lasers proposed in this work show potential applications in wearable devices and medical diagnosis. [ABSTRACT FROM AUTHOR]

Flexible electrochemical sensors can adhere to any bendable surface with conformal contact, enabling continuous data monitoring without compromising the surface’s dynamics. Among various materials that have been explored for flexible electronics, metal–organic frameworks (MOFs) exhibit dynamic responses to physical and chemical signals, offering new opportunities for flexible electrochemical sensing technologies. This review aims to explore the role of electrocatalysis in MOF films specifically designed for flexible electrochemical sensing applications, with a focus on their design, fabrication techniques, and applications. We systematically categorize the design and fabrication techniques used in preparing MOF films, including in situ growth, layer-by-layer assembly, and polymer-assisted strategies. The implications of MOF-based flexible electrochemical sensors are examined in the context of wearable devices, environmental monitoring, and healthcare diagnostics. Future research is anticipated to shift from traditional microcrystalline powder synthesis to MOF thin-film deposition, which is expected to not only enhance the performance of MOFs in flexible electronics but also improve sensing efficiency and reliability, paving the way for more robust and versatile sensor technologies.

Abstract A pulsed laser annealing method is utilized to directly synthesize nickel silicide (NiSi) as a contact material to improve the contact of electric devices. Three laser wavelengths, 355 nm (ultraviolet laser), 532 nm (green laser), and 1064 nm (infrared laser), are used for the NiSi synthesis during the pulsed laser annealing process. A NiSi phase with low sheet resistance is formed by an ultraviolet laser annealing (ULA) process without damaging the polyimide (PI) substrate. With the integration of the ULA process‐induced NiSi into p‐nnel MOSFET (PMOS) and n‐channel MOSFET (NMOS) devices, the on/off ratio improves significantly, and the field‐effect mobility increases by 30% because of the reduction in contact resistance from 21 to 8.5 kΩ. In addition to the PMOS and NMOS, the gains of the CMOS inverter at different Vdd values are improved by at least 30%. Moreover, the static noise margin of 6T‐SRAM is elevated from 0.82 to 1 V at Vdd = 4 V. The ability of the ULA process to synthesize a high‐quality NiSi layer on a flexible substrate is demonstrated. The integration of NiSi into electrical devices offers a new pathway for improving the electrical behavior of flexible devices.

There is a growing demand for flexible pressure sensors in environmental monitoring and human–robot interaction robotics. A flexible and susceptible sensor can discriminate multidirectional pressure, thus effectively detecting signals of small environmental changes and providing solutions for personalized medicine. This paper proposes a multidimensional force detection sensor inspired by a wind chime structure with a three-dimensional force structure to detect and analyze normal and shear forces in real time. The force-sensing structure of the sensor consists of an upper and lower membrane on a polydimethylsiloxane substrate and four surrounding cylinders. A piezoelectric hemisphere is made of BTO/PVDF/PDMS composite material. The sensor columns in the wind chime structure surround the piezoelectric layer in the middle. When pressure is applied externally, the sensor columns are connected to the piezoelectric layer with a light touch. The piezoelectric hemisphere generates a voltage signal. Due to the particular structure of the sensor, it can accurately capture multidimensional forces and identify the direction of the external force by analyzing the position of the sensor and the output voltage amplitude. The development of such sensors shows excellent potential for self-powered wearable sensors, human–computer interaction, electronic skin, and soft robotics applications. [ABSTRACT FROM AUTHOR]

Photothermoelectric (PTE) devices have emerged as highly promising technological advancements in energy harvesting and electronics. However, the development of PTE devices faces challenges in achieving exceptional performance, adaptable flexibility, durable stability, and compatibility within a system. This study proposes a self-powered PTE device that operates at room temperature by integrating molybdenum carbide (Mo2C)/ Poly(3,4-ethylene-dioxythiophene)-poly (styrene sulfonate) (PEDOT: PSS) nanomaterials with a flexible poly (ethylene terephthalate) (PET) substrate. We achieve precise control over the device size through a spray coating technique and employ a laser-involved mask technique for efficient fabrication. Our Mo2C/PEDOT: PSS devices demonstrate remarkable long-term stability and outstanding flexibility and can be folded and twisted without increasing performance degradation. The devices exhibit a responsivity of 4.2 V W−1 and a detectivity of 1.2 × 108 cm Hz1/2 W−1 at 973 K black-body radiation. By employing these advantages, we integrate two potential systems—the motion tracking system and the non-destructive (NDT) imaging system—that showcase time-tracking of human radiation and high-resolution imaging. These promising platforms expand the potential of PTE technology into diverse applications, including industry, aerospace, public health, security, and wearable monitoring.

In this study, we demonstrated organic light-emitting diodes (OLEDs) outcoupling with a flexible polydimethylsiloxane (PDMS) film with a micro-convex structure using the breath figure (BF) method. We can easily control the micro-convex pattern by adjusting the concentration of polystyrene and the humidity during the BF process. As process conditions to fabricate the micro-convex structure, polymer concentrations of 10, 20, 40, and 80 mg/mL and 60, 70, and 80% relative humidity were used. To evaluate the optical properties, we analyzed the transmission, diffusion, and electroluminescence with or without the micro-convex structure on the OLEDs. The shape and density of the micro-convex structure are related to its optical properties and outcoupling and we have experimentally demonstrated this. By applying a micro-convex structure, it achieved up to a 42% improvement in the external quantum efficiency compared to bare OLEDs (without any light extraction film). We expect the fabricated flexible light extraction film to be effective for outcoupling and applicable to flexible devices. [ABSTRACT FROM AUTHOR]

In this paper, wave power extraction from a floating Clam-type wave energy converter is investigated. The device is mainly composed of a Clam, which is formed from two pieces of floating flaps hinged at a submerged body. The Clam is closed by a flexible impermeable bag with the two hinged floating flaps kept apart by a Power Take-Off system. As waves propagate through the device, the Clam motion of the device is excited, which can be used to drive the Power Take-Off system to capture wave power. To evaluate the response and also the wave power absorption of the device, a mathematical model is developed based on the linear potential flow theory, in which a generalised mode method is adopted to model the Clam action. Theoretical expressions of the maximum wave power absorption and the corresponding optimised Power Take-Off system and mooring parameters are derived. Good agreement between the present numerical results of the device response and the physical observations is obtained. The validated model is then applied to do a series of case studies. It is revealed that the optimised Power Take-Off stiffness and mooring stiffness are independent of the Power Take-Off damping. The maximum wave power absorption can be achieved when the device is fixed in heave mode or free-floating without any constraints from the mooring system. • We developed a mathematical model to study the performance of a Clam-type device. • A generalised mode method was adopted to model the Clam action. • We derived the expressions of the maximum wave power output and the optimised PTO. • The numerical results agree well with the corresponding measured physical data. The optimised PTO stiffness and mooring stiffness are independent of the PTO damping. [ABSTRACT FROM AUTHOR]

Bi 2 Te 3 -based flexible thermoelectric power generator is a competitive candidate for wearable electronics. However, the strongly coupled Seebeck coefficient and electrical conductivity limits thermoelectric performance of p-type Bi 0.5 Sb 1.5 Te 3 -based flexible thin films (f-TFs). In this work, we report Ti-doping by a magnetron co-sputtering method can strengthen the texture orientation of as-prepared Bi 0.5 Sb 1.5 Te 3 -based f-TFs and correspondingly contribute to a high electrical conductivity of 532.69 S cm−1 at room temperature. Under simultaneously optimized carrier concentration (n h), a high Seebeck coefficient of ∼196.15 μV K−1 and an high room-temperature power factor of ∼19.67 μW cm−1 K−2 have been achieved. A 3 single-leg flexible thermoelectric device demonstrates high applicability. Simultaneously, the as-prepared Ti-doped Bi 0.5 Sb 1.5 Te 3 f-TFs and device demonstrate high bending resistance as evidenced by the <10% change of thermoelectric performance before and after bending. Our study indicates that Ti-doping can simultaneously tune the texture orientation and n h of Bi 0.5 Sb 1.5 Te 3 -based f-TFs and achieve high thermoelectric performance. [ABSTRACT FROM AUTHOR]

The resistive type of graphite/WO3 nanocomposite-based humidity sensor is fabricated through screen printing on a flexible polyethylene terephthalate substrate. Three different nanocomposite-based humidity sensors have been fabricated and analyzed for their humidity-sensing characteristics. The structure elucidation of the nanocomposite was carried out using x-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. By exposing the printed humidity sensor to relative humidity ranging from 11% to 97% at room temperature, its capabilities were studied. The relative resistance, sensitivity, dynamic response, and hysteresis were determined for all three devices, and they showed maximum responses towards relative humidity changes with the highest sensitivity of ≈ 60.8% and excellent hysteresis curves (maximum change of ≈ 1%). The screen-printed flexible humidity sensor exhibited less than a 5% change in the internal electrical resistance when subjected to various bending angles. [ABSTRACT FROM AUTHOR]

For flexible solid‐state electronics, it is essential to accelerate the transition to renewable materials and environmentally friendly manufacturing procedures. Symmetric supercapacitors (SCs) have a limited voltage window and capacity, hampering their use in practical applications such as portable electronics, hybrid vehicles, and transportation. To improve the energy density of supercapacitors, the strategy of using an advanced pseudo‐capacitive electrode in an asymmetric device configuration is feasible and effective. Here, we report on the design and synthesis of hierarchical honeycomb‐like morphology with controlled Ni/Co molar ratios of NiCo2O4 (NCO) coatings on flexible stainless‐steel substrates utilizing high cathodic overpotential deposition. The NCO electrode retains 90.5% of the three‐electrode capacitance (911 F g−1, or 594 C g−1) even after increasing the current density to 10 A g−1 (∼10 times). Furthermore, we have fabricated a 1.5 V asymmetric supercapacitor (ASC, NCO//AC); such a device delivers maximum specific energy and specific power of 76.8 Wh kg−1 and 16858 W kg−1 in 2 M KOH electrolyte and excellent cycling stability (∼88% retention after 5000 cycles). [ABSTRACT FROM AUTHOR]

This work presents the evaluation of the electrical behavior of a flexible photoconductor with a planar heterojunction architecture made up of organic semiconductor films deposited by high vacuum evaporation. The heterojunction was characterized in its morphology and mechanical properties by scanning electron microscopy and atomic force microscopy. The electrical characterization was carried out through the approximations of ohmic and SCLC (Space-Charge Limited Current) behaviors using experimental J–V (current density–voltage) curves at different voltages and under different light conditions. The optimization of the photoconductor was carried out through annealing and accelerated lighting processes. With these treatments, the Knoop Hardness of the flexible photoconductor has reached a value of 8 with a tensile strength of 5.7 MPa. The ohmic and SCLC approximations demonstrate that the unannealed device has an ohmic behavior, whereas the annealed device has an SCLC behavior, and after the optimization process, an ohmic behavior and a maximum current density of 0.34 mA/mm2 were obtained under blue light. The approximations of the device’s electron mobility (μn) and free carrier density (n0) were performed under different light conditions, and the electrical activation energy and electrical gap were obtained for the flexible organic device, resulting in appropriate properties for these applications.