Multiple Bending Research Articles

Research on Energy Harvesting of Piezoelectric Vibration Using 2D ABH Structure

The acoustic black hole (ABH) effect can achieve energy concentration by changing the structural characteristics and reducing the propagation velocity of curved waves. This way of energy gathering provides a new idea for the harvesting of vibration energy. In this study, an energy collection structure with 2D ABH characteristics is proposed and studied, which can effectively provide energy harvesting efficiency. According to the theory of geometric acoustics, the size of the piezoelectric patch is designed to be smaller than the half wavelength of the bending wave at the centre of ABH, so as to avoid the situation of positive and negative charge cancellation caused by multiple bending waves on a single piezoelectric patch, and improve the energy utilization rate. The electromechanical coupling model of 2D ABH structure and piezoelectric energy collection circuit was established to study the energy harvesting performance of the plate with 2D ABH structure under transient and steady state conditions. The results show that the 2D ABH structure can effectively increase the frequency width range of vibration energy harvesting and improve energy harvesting efficiency

Control of electronic band profiles through depletion layer engineering in core\u2013shell nanocrystals

Fermi level pinning in doped metal oxide (MO) nanocrystals (NCs) results in the formation of depletion layers, which affect their optical and electronic properties, and ultimately their application in smart optoelectronics, photocatalysis, or energy storage. For a precise control over functionality, it is important to understand and control their electronic bands at the nanoscale. Here, we show that depletion layer engineering allows designing the energetic band profiles and predicting the optoelectronic properties of MO NCs. This is achieved by shell thickness tuning of core–shell Sn:In2O3–In2O3 NCs, resulting in multiple band bending and multi-modal plasmonic response. We identify the modification of the band profiles after the light-induced accumulation of extra electrons as the main mechanism of photodoping and enhance the charge storage capability up to hundreds of electrons per NC through depletion layer engineering. Our experimental results are supported by theoretical models and are transferable to other core-multishell systems as well.

Mechanically robust Ti3C2Tx MXene/Carbon fiber fabric/Thermoplastic polyurethane composite for efficient electromagnetic interference shielding applications

It is a challenge to design Ti3C2Tx MXene-based electromagnetic interference (EMI) shielding composites with excellent mechanical properties. Herein, a highly robust, flexible and durable Ti3C2Tx MXene/carbon fiber fabric/thermoplastic polyurethanes (Ti3C2Tx MXene/CFf/TPU) composite was fabricated through simple electrohydrodynamic atomization deposition, layer-by-layer stacking and hot pressing technology. The synergistic strengthening effect of van der Waals forces and covalent bonds can improve the tensile strength of the composite up to170.2 MPa, which is far greater than that of other MXene-based composites previously reported. In addition, the EMI shielding performance of the Ti3C2Tx MXene/CFf/TPU composite also improved with increasing MXene mass fraction, reaching 40.4 dB, which can be attributed to the dielectric loss provided by conductive fillers and the enhanced absorption within the sandwich structure. More interestingly, the composite retained excellent resistance stability, EMI-SE stability and flexibility, even after multiple bending and releasing cycles. This work provides a facile and environmentally-friendly method for preparing composites with excellent EMI shielding properties and mechanical properties, which may provide more possibilities for applications in intelligent wear and electronic wireless communication equipment.

Complete stress release in monolayer ALD-Al2O3 films based on mechanical equilibrium homeostasis to realize a bending radius of 1 mm.

Low-temperature-deposited, transparent, high-barrier-performance atomic layer deposition (ALD) Al2O3 films are widely utilized to protect organic optoelectronic devices. However, because the internal compression residual stresses result in poor mechanical properties, these films are unable to realize independent encapsulation. In this work, we propose a pre-bending and substrate thermal expansion process to fabricate low-residual-stress ALD-Al2O3 films by multistep adjustment of mechanical equilibrium homeostasis, compare and analyze the key properties of the films to determine the optimal processing conditions, and adjust the surface area differences between the film and the substrate to acquire a flat-bottom encapsulation substrate. Therefore, fewer cracks form in ALD-Al2O3 deposited at 40 °C, and no significant increase in the water-vapor-transmission rate (WVTR) occurred after multiple bending processes at a 3 mm radius. Furthermore, both the bending radius for the first crack generation and crack saturation density were optimal, resulting in excellent mechanical stability, and a bending radius of 1 mm was achieved. Finally, we confirm the feasibility of the monolayer ALD-Al2O3 prepared by our process for applications in OLEDs. The encapsulated OLED maintained 94% of its initial efficiency after 10 days of bending in a harsh environment at 30 °C and 90% relative humidity.

Performance improvement of flexible ultraviolet photodetectors based on ZnO nanorod arrays by hydrothermal method with assistance of polyethyleneimine

Investigations on the high-performance flexible ultraviolet photodetectors have been becoming one of the interesting research focuses in recent years. ZnO is considered as suitable material for ultraviolet photodetection due to its wide bandgap (~3.37 eV). In this work, ZnO nanorod arrays were prepared using the hydrothermal method at the temperature of 70 ℃ on flexible substrates. Polyethyleneimine (PEI) was added into hydrothermal solution as the growth additive to achieve the performance improvement of the ZnO nanorod arrays ultraviolet photodetector. SEM, XRD, absorption spectroscopy, Raman spectroscopy and XPS were employed to characterize the morphology, crystallinity, optical properties and chemical composition. The introduction of PEI adjusts the growth process of ZnO nanorod arrays and affects the distribution of defect states, which brings out the improvement of the optoelectronic performance of ZnO nanorod arrays ultraviolet photodetectors. Compared with pure ZnO, the higher photo to dark current ratio and responsivity, and quicker time response speed are demonstrated in the PEI-assisted ZnO nanorod arrays photodetectors. And more photoresponse parameters are also discussed and compared. Furthermore, the photodetectors also display outstanding mechanical flexibility and robustness under multiple bending cycle tests. Our work presents a potential approach for improving the optoelectronic performance of simple-operated flexible ultraviolet photodetectors.

Flexible Titanium Nitride/Germanium-Tin Photodetectors Based on Sub-Bandgap Absorption.

We report an enhanced performance of flexible titanium nitride/germanium-tin (TiN/GeSn) photodetectors (PDs) with an extended photodetection range based on sub-bandgap absorption. Single-crystalline GeSn membranes transfer-printed on poly(ethylene terephthalate) are integrated with plasmonic TiN to form a TiN/GeSn heterojunction. Formation of the heterojunction creates a Schottky contact between the TiN and GeSn. A Schottky barrier height of 0.49 eV extends the photodetection wavelength to 2530 nm and further enhances the light absorption capability within the detection range. In addition, finite-difference time-domain simulation proves that the integration of TiN and GeSn could enhance average absorption from 0.13 to 0.33 in the near-infrared (NIR) region (e.g., 1400-2000 nm) and more than 70% of light is absorbed in TiN. The responsivity of the fabricated TiN/GeSn PDs is increased from 30 to 148.5 mA W-1 at 1550 nm. There is also an ∼180 nm extension in the optical absorption wavelength of the flexible TiN/GeSn PD. The enhanced performance of the device is attributed to the absorption and separation of plasmonic hot carriers via TiN and the TiN/GeSn junction, respectively. The effect of external uniaxial strain is also investigated. A tensile strain of 0.3% could further increase the responsivity from 148.5 to 218 mA W-1, while it is decreased to 102 mA W-1 by 0.25% compressive strain. In addition, the devices maintain stable performance after multiple and long bending cycles. Our results provide a robust and cost-effective method to extend the NIR photodetection capability of flexible group IV PDs.

Carbon Nanotube Based Robust and Flexible Solid-State Supercapacitor.

All solid-state flexible electrochemical double-layer capacitors (EDLCs) are crucial for providing energy options in a variety of applications, ranging from wearable electronics to bendable micro/nanotechnology. Here, we report on the development of robust EDLCs using aligned multiwalled carbon nanotubes (MWCNTs) grown directly on thin metal foils embedded in a poly(vinyl alcohol)/phosphoric acid (PVA/H3PO4) polymer gel. The thin metal substrate holding the aligned MWCNT assembly provides mechanical robustness and the PVA/H3PO4 polymer gel, functioning both as the electrolyte as well as the separator, provides sufficient structural flexibility, without any loss of charge storage capacity under flexed conditions. The performance stability of these devices was verified by testing them under straight and bent formations. A high value of the areal specific capacitance (CSP) of ∼14.5 mF cm-2 with an energy density of ∼1 μW h cm-2 can be obtained in these devices. These values are significantly higher (in some cases, orders of magnitude) than several graphene as well as single-walled nanotube-based EDLC's utilizing similar electrolytes. We further show that these devices can withstand multiple (∼2500) mechanical bending cycles, without losing their energy storage capacities and are functional within the temperature range of 20 to 70 °C. Several strategies for enhancing the capacitive charge storage, such as physically stacking (in parallel) individual devices, or postproduction thermal annealing of electrodes, are also demonstrated. These findings demonstrated in this article provide tremendous impetus toward the realization of robust, stackable, and flexible all solid-state supercapacitors.

Environmentally stable one-dimensional copper halide based ultra-flexible composite film for low-cost X-ray imaging screens

Environmentally stable, low cost, large stokes shift, adjustable area and flexibility are basic factors to prepare scintillator films for their commercial application. Here, a low cost (∼3 $/g) room-temperature ligand-assisted reprecipitation method is used to synthesize one-dimensional crystal structure based on Rb2CuX3 (X = Br, Cl). Rb2CuBr3 exhibits quite high mass yield of 90% with high Photoluminescence quantum yield (PLQY) of 59.06%. Importantly, its bright blue emission (90 nm stokes shift) is consistent with the highest optical detection efficiency wavelength range of commercial SiPM. Further characterizations point out that such effective blue emission comes from the recombination of excitons rather than the defects or combination of electron-hole pairs. And the existing strong exciton-photon coupling is conducive to the formation of self-trapped excitons (STEs). Finally, uniform and adjustable area Rb2CuBr3-polystyrene composite films have been successfully obtained. It's fascinating that the films exhibit ultra-flexibility (unchanged performance after multiple bending of 400 times) and excellent stability (subtle attenuation after 30 days of storage in a harsh environment). As an X-ray imaging screen, it presents a sensitive scintillation response to X-ray signals with superior linearity with high-quality images. Therefore, our prepared Rb2CuBr3 scintillator shows great commercial prospects in the field of flexible X-ray detection.

Classification of wheelchair pressure relief maneuvers using changes in center of pressure and weight on the seat

Background Pressure injuries from prolonged sitting are a significant problem for wheelchair users incurring high costs in healthcare expenditures and reducing quality-of-life. There is a need to improve pressure relief training and adherence in a variety of settings. Objective To identify effective common wheelchair pressure relief (PR) manoeuvres based on changes to users’ seated centre of pressure (CoP) and seated weight. Participants 20 individuals who use manual wheelchairs as their primary means of mobility Methods Participants performed 5 types of PR including seated push-ups, leftward, rightward, forward, and backward leans—while sitting in a wheelchair equipped with a custom instrumented seat pan support. Data were analysed using both clustering and decision tree approaches to identify types of PR. Results Both clustering and decision tree approaches were able to identify and classify PR though neither could accurately distinguish between forward and backward PR. Conclusion Changes in the centre of pressure and the total weight on the wheelchair’s seat can be used to automatically characterise type, amplitude and duration of pressure relief manoeuvres. Building such a classification and quality assessment scheme into an algorithm could enable a virtual coaching system to track users’ pressure relief behaviour and make suggestions to improve adherence with clinical recommendations. IMPLICATIONS FOR REHABILITATION Multiple bending beam load cells can be used to measure wheelchair users’ seated centre of pressure independent of type of cushion used. Both cluster analysis and decision tree algorithms can classify commonly practiced pressure reliefs by measuring changes to the centre of pressure and total weight on the wheelchair’s seat. The combination of force sensing for centre of pressure determination and either algorithm could serve as the basis for an application to coach wheelchair users to do effective pressure reliefs.

Modification of the Johnson–Cook Material Model for Improved Simulation of Hard Milling High-Performance Steel Components

Understanding the effect of thermomechanical loads during finish cutting processes, in our case hard milling, on the surface integrity of the workpiece is crucial for the creation of defined quality characteristics of high-performance components. Compared to computationally generated modifications by simulation, the measurement-based determination of material modifications can only be carried out selectively and on a point-by-point basis. In practice, however, detailed knowledge of the changes in material properties at arbitrary points of the high-performance component is of great interest. In this paper, a modification of the well-known Johnson–Cook material model using the finite element software Abaqus is presented. Special attention was paid to the kinematic hardening behavior of the used steel material. Cyclic loads are relevant for the chip formation simulation because, during milling, after each cut, the material under the surface is loaded plastically several times and not necessarily in the same direction. Therefore, in analogy, multiple bending was investigated on samples made of 42CrMo4. A pronounced Bauschinger effect was observed in the bending tests. An adaptation of the material model to the results of the bending tests was only possible to a limited extent without kinematic hardening, which is why the Johnson–Cook model was supplemented by the Armstrong–Frederick hardening approach. The modified Johnson–Cook–Armstrong–Frederick material model was developed for practical use as a VUMAT and verified by bending tests for simulation use.

Differentiation of Multiple Mechanical Stimuli by a Flexible Sensor Using a Dual-Interdigital-Electrode Layout for Bodily Kinesthetic Identification

Human bodily kinesthetic sensing is generally complicated and ever-changing due to the diversity of body deformation as well as the complexity of mechanical stimulus, which is different from the unidirectional mechanical motion. So, there exists a huge challenge for current flexible sensors to accurately differentiate and identify what kind of external mechanical stimulus is exerted via analyzing digital signals. Here, we report a flexible dual-interdigital-electrode sensor (FDES) that consists of two interdigital electrodes and a highly pressure-sensitive porous conductive sponge. The FDES can precisely identify multiple mechanical stimuli, e.g., pressing, positive bending, negative bending, X-direction stretching, and Y-direction stretching, and convert them into corresponding current variation signals. Moreover, the FDES exhibits other exceptional properties, such as high sensitivity, stretchability, large measurement range, and outstanding stability, accompanied by simple structural design and low-cost processing simultaneously. Additionally, our FDES successfully identifies various complex activities of the human body, which lays a foundation for the further development of multimode flexible sensors.

Breaking bending limit of difficult-to-form titanium tubes by differential heating-based reconstruction of neutral layer shifting

Achieving small-radius bending of difficult-to-form tubular materials with large-diameter, thin-walled (LDTW, D/t > 20) geometry — as well as the properties of high-strength poor-hardening (HSPH) — is a continual target and challenging issue in the aerospace, marine, and healthcare industries. Based on the theoretical analysis of neutral layer shifting reconstruction (NLSR) by positively utilizing the temperature-dependent tension-compression (T-C) asymmetry of tubes, an innovative differential heating-based rotary draw bending (DH-RDB) method is designed, i.e., applying differential working temperatures at the intrados (Tin) and extrados (Tout) of tubes during forming to proactively coordinate the non-uniform deformation and thus prevent multiple forming defects to break the bending limit. To verify the above concept, the temperature-dependent evolution of the T-C asymmetry of titanium tubes was characterised — using commercial pure titanium (CP–Ti) tubes as case materials — and numerically implemented into the thermo-mechanical coupled three-dimensional finite element (3D-FE) model of the DH-RDB process. The influence of two heating schemes–i.e., overall heating and differential heating at the extrados and intrados of the tube — on bending formability was quantitatively assessed regarding multiple bending defects, such as wrinkling, over-thinning, and cross-section flattening. It was found that by introducing differential heating, the design and optimisation space for NLSR in tube bending is enlarged. The overall heating increases the work hardening of titanium tubes and thus restrains wrinkling during bending. Furthermore, the coupling effects of the increased compression-tension flow stress ratio (CTFSR) and decreased friction force under differential heating of Tin < Tout slightly aggravated the inward neutral layer shifting (NLS) but reduced wall-thinning and cross-section flattening. Following the above critical understanding, a series of carefully designed bending experiments were conducted to validate the capability of the DH-RDB to break the bending limit. This proves that the differential heating-based NLSR can be used to positively coordinate T-C non-uniform deformation to break the bending limit of difficult-to-form tubular materials.

Flame-Retardant, Highly Conductive, and Low-Temperature-Resistant Organic Gel Electrolyte for High-Performance All-Solid Supercapacitors.

Traditional liquid electrolytes are volatile, flammable, and easy to leak, which makes the energy storage device easy to burn and explode in the case of overcharge and short circuit. Here, by utilizing the active P-H bond of a flame retardant (DOPO) to graft onto the polymer chain, flame-retardant organic gel electrolytes were fabricated to address these issues. The gel electrolyte had good ionic conductivity of 4 mS cm-1 at 20 °C and good flame retardant ability. By changing the molar ratio of the monomers and the salt concentrations, the mechanical strength of the gel electrolyte could be adjusted (maximum stress≈28 KPa, maximum strain≈305 %). The transport mechanism of lithium ions in the gel polymer electrolyte was proposed. The gel electrolyte-assembled supercapacitor (SC) possessed better electrochemical properties than that of SC assembled by liquid electrolyte. Importantly, the gel-based SC remained basically unchanged under multiple bending cycles. Additionally, the gel electrolyte had good low-temperature tolerance (0.1 mS cm-1 at -40 °C). The gel electrolyte-assembled SC could work normally in the temperature range of -20 to 60 °C. The multiple advantages of gel electrolyte expand the applications in ionic conductor and energy storage devices.

Novel Self-Directing Single-Polymer Jet Developing Layered-Like 3D Buckled Microfibrous Scaffolds for Tissue Engineering Applications.

Electrospinning is a promising technique for the fabrication of bioscaffolds in tissue engineering applications. Pertaining issues of multiple polymer jets and bending instabilities result in random paths which lend poor controllability over scaffolds morphology for affecting the porosity and mechanical stability. The present study alleviates these challenges by demonstrating a novel self-directing single jet taking a specifically patterned path to deposit fibers into circular and uniform scaffolds without tuning any externally controlled parameters. High-speed camera observation revealed that the charge retention and dissipation on the collected fibers caused rapid autojet switching between the two jetting modes, namely, a microcantilever-like armed jet motion and a whipping motion, which sequentially expand the area and thickness of the scaffolds, respectively, in a layered-like fashion. The physical properties showed that the self-switching dual-jet modes generated multilayered microfibrous scaffolds (MFSs) with dual morphologies and varied fiber packing density, thereby establishing the gradient porosity and mechanical strength (through buckled fibers) in the scaffolds. In vitro studies showed that as-spun scaffolds are cell-permeable hierarchical 3D microporous structures enabling lateral cell seeding into multiple layers. The cell proliferation on days 6 and 9 increased 21% and 38% correspondingly on MFSs than on nanofibrous scaffolds (NFSs) done by conventional multijets electrospinning. Remarkably, this novel and single-step process is highly reproducible and tunable for developing fibrous scaffolds for tissue engineering applications.

Comparison of the mechanical properties of polymer blend and main-chain conjugated copolymer films with donor–acceptor heterojunctions

To implement a highly flexible polymer solar cell (PSC), the mechanical properties of the material constituting the active layer are considered crucial, having a significant influence on the stability of the device. In this study, the mechanical properties of a main-chain conjugated copolymer (PBDT2T-b-PNDI2T) containing donor- and acceptor-based macromolecular species in the polymer backbone was measured and compared with that of donor and acceptor polymer blend film (P(BDT2T):P(NDI2T)). It was observed that the PBDT2T-b-PNDI2T active layer exhibited a higher crack-onset-strain and toughness compared to P(BDT2T):P(NDI2T) active layer. Correspondingly, the YTRON/polyethylene naphthalate (PEN) based flexible PSC with a PBDT2T-b-PNDI2T active layer was used, which exhibited superior mechanical stability under multiple bending conditions. The results of this study indicate that flexible PSCs with excellent durability can be developed by replacing the polymer blend used for all-PSCs with PBDT2T-b-PNDI2T as the active layer material for highly efficient future applications.

Determining patterns in the use of finishing formulations for trimming the Crust leather

This paper has considered the possibility of using new finishing formulations to finish the Crust leather, manufactured from cattle raw materials aimed to finish shoes and leather garments.The quality indicators of finishing formulations and their elementary chemical composition have been investigated. It was found that the finishing formulations possess a high covering capacity due to the presence of mineral pigments in their composition. X-ray fluorescent analysis has proven that the presence of chromium pigments and copper compounds renders the green color to the composition; the compounds of cobalt, copper, iron, chromium ‒ blue color; cobalt compounds ‒ reddish-brown color.It has been established that the finishing formulations are resistant to the effect of electrolytes of different nature over a wide pH interval, from 2 to 11.When determining the uniformity of the composition by using a chromatography method involving fan-shaped paper, it was found that the composition of blue has a pronounced purple hue, of reddish-brown – red.The effectiveness of the use of finishing formulations to finish the Crust leather has been proven by determining the indicators of its quality. The finishing formulations give the Crust high resistance to dry (exceeding 500 rotations) and wet friction (exceeding 150 rotations), multiple bending (exceeding 50,000 rotations), the effect of water (2 to 5 points), and organic solvents (2 to 4 points). At the same time, the finishing formulations are characterized by rapid diffusion into the structure of the leather with a natural front surface with the simultaneous provision of specific properties to it. Specifically: water-repelling properties (hydrophobicity), shine, wax grain, matte, saturated homogeneous color. The leather with the introduced finishing formulations does not require fixing the resulting coating with water-based varnish.It is recommended to use the finishing formulations in the production of Crust leather shoe top by applying them onto the surface by spraying or using a brush to create the desired effect

Fabrication of 3D ordered needle-like polyaniline@hollow carbon nanofibers composites for flexible supercapacitors

Carbon nanofiber-based supercapacitors have broad prospects in powering wearable electronics owing to their high specific capacity, fast charge/discharge process, along with long-cycling life. Herein, a poly(acrylonitrile-co-β-methylhydrogen itaconate) copolymer was prepared and used to synthesize flexible hollow carbon nanofibers (HCNFs) via an electrospinning method without breaking after multiple bending. Subsequently, the inner and outer surfaces of HCNFs were evenly covered with ordered needle-like polyaniline (PANI) through in-situ polymerization methods to obtain three-dimensional flexible HCNFs/PANI composites, which exhibited a high capacity 1196.7 F/g at 1 A/g and good cycling stability (90.1% retention at 5 A/g after 3000 cycles). The symmetrical supercapacitor based on the HCNFs/PANI composites also delivered an outstanding electrochemical performance with high energy/power density (60.28 Wh/kg at 1000 W/kg) and superior cycling durability (90% capacitance retention after at 5 A/g 3000 cycles), which confirmed that the HCNFs/PANI composites had a wide application potential in flexible energy storage devices.

Heterogeneous silicon rubber composite foam with gradient porous structure for highly absorbed ultra-efficient electromagnetic interference shielding

Heterogeneous silicone rubber (VMQ)/silver plated glass fiber (Ag@GF)/multiwalled carbon nanotubes (MWCNT)/ferroferric oxide (Fe3O4) composite foams with gradient porous structure were fabricated through layer by layer combination and supercritical carbon dioxide (scCO2) foaming. The average electromagnetic interference shielding effectiveness (EMI SE) and absorption coefficient (A) of the composite foam are as high as 78.6 dB and 0.82 respectively, because of the reasonable progressive dissipation mechanism. The resonance cancellation caused by the encounter of incident and reflected electromagnetic (EM) waves further improved the microwave absorbing performance of the foam, and an absorption ratio of up to 94% can be obtained at 7.68 GHz. Moreover, the composite foam exhibits excellent stability of EMI shielding performance under multiple bending. This composite foam has great application prospects in the field of EM protection of wearable flexible electronics, high-power instruments and the forthcoming 5th-Generation communication products.

Flexible transparent solar blind ultraviolet photodetector based on amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; grown on mica substrate

Solar-blind deep-ultraviolet (UV) photodetectors (PDs) based on the super-wide bandgap semiconductor material Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is one of the hot topics of current research, but how to prepare high-performance Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-based solar-blind PDs in the field of flexible and transparent optoelectronics still faces challenges. In this work, an amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; film with high transmittance is grown on a flexible mica substrate by using the radio frequency magnetron sputtering technology. On this basis, using AZO as an electrode material, a transparent metal-semiconductor-metal (MSM) structured solar-blind deep ultraviolet photodetector based amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; film is fabricated, and the performance of PD in the planar state and after multiple bending are systematically compared and analyzed. The results show that the amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; based transparent PD has ultra-high visible light transparency and shows good solar-blind ultraviolet photoelectric characteristics. The responsivity of the PD under 254 nm light is 2.69 A/W, and the response time and the recovery time are 0.14 s and 0.31 s, respectively. After bending 300 times, the PD has a photoresponse behavior similar to its planar state, and the performance of the PD has no obvious attenuation phenomenon, showing good flexibility and stability. This work proves that AZO can be used as the electrode material of the next generation of flexible and visible light transparent Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; based photodetectors, and provides a reference for developing the high-performance flexible and transparent solar-blind deep ultraviolet photodetectors.

Protein-based soft actuator with high photo-response and easy modulation for anisotropic cell alignment and proliferation in a liquid environment.

Cell alignment and elongation, which are critical factors correlated with differentiation and maturation in cell biology and tissue engineering, have been widely studied in organisms. Several strategies such as external mechanical strain, geometric topography, micropatterning approaches, and microfabricated substrates have been developed to guide cell alignment, but these methodologies cannot be used for easily denatured natural proteins to modulate the cell behaviour. Herein, for the first time, a novel biocompatible light-controlled protein-based bilayer soft actuator composed of elastin-like polypeptides (ELPs), silk fibroin (SF), graphene oxide (GO), and reduced graphene oxide (rGO), named ESGRG, is developed for efficiently driving cellular orientation and elongation with anisotropic features on soft actuator via remote NIR laser exposure. The actuation of ESGRG could be manipulated by modulating the intensity of NIR and the relative ratio of GO to rGO for promoting myoblasts alignment and nucleus elongation to generate different motions. The results indicate that the YAP and MHC protein expression of C2C12 skeletal muscle cells on ESGRG can be rapidly induced and enhanced by controlling the relative ratio of rGO/GO = 1/4 at a multiple-cycle stimulation with a very low power intensity of 1.2 W cm-2 in friendly liquid environments. This study demonstrates that the ESGRG hydrogel actuator system can modulate the cell-level behaviors via light-driven cyclic bending-motions and can be utilized in applications of soft robotic and tissue engineering such as artificial muscle and maturation of cardiomyocytes.