Recent years have seen a considerable growth of research interests in developing novel technologies that permit designable manufacture and controllable manipulation of actuators. Among various ...fabrication and driving strategies, light has emerged as an enabler to reach this end, contributing to the development of actuators. Several accessible light‐mediated manufacturing technologies, such as ultraviolet (UV) lithography and direct laser writing (DLW), are summarized. A series of light‐driven strategies including optical trapping, photochemical actuation, and photothermal actuation for controllable manipulation of actuators is introduced. Current challenges and future perspectives of this field are discussed. To generalize, light holds great promise for the development of actuators.
Recent advances in light‐mediated manufacture and manipulation of actuators are highlighted. Several optical fabrication technologies, including UV lithography and direct laser writing, and various photo‐driven strategies, such as optical trapping, and photochemical and photothermal actuation are reviewed. Emerging trends and future perspectives of light‐enabled actuators are discussed.
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Topological acoustics has recently revolutionized fundamental concepts of acoustic propagation, giving rise to strikingly unique acoustic edge modes immune to backscattering. Despite the rapid ...progress in this field, simultaneous realization of reconfigurability, intelligentization, and automatic control over acoustic propagation paths is posing a great challenge. This challenge is overcome by proposing the concept of a programmable acoustic topological insulator based on two digital elements “0” or “1,” which consist of honeycomb‐lattice sonic crystals made of cylindrical rods with different diameters. The acoustic propagation paths in the topological insulators can be controlled automatically by programming different coding sequences, which arises from efficient transformation of pseudospin‐dependent edge modes on both interfaces of the digital elements. More importantly, a unique unit is experimentally fabricated that has either a “0” or “1” response automatically manipulated by an air cylinder, and design topological insulators with programmable functionality, to realize three digital acoustic devices, such as a single‐pole double‐throw switch, a single‐pole single‐throw switch, and a tunable logic gate. The proposed programmable topological insulators may enable future intelligent acoustic devices with exciting reconfigurable and programmable functionalities, which may lead to important advances in various applications, such as integrated acoustics, acoustic security, and information processing.
Programmable acoustic topological insulators (ATIs) enable future intelligent acoustic devices with reconfigurable and programmable functionalities. A unique unit of ATI with either “0” or “1” response automatically manipulated by an air cylinder is fabricated. By programming coding sequences of ATIs, three digital acoustic devices, including a single‐pole double‐throw switch, a single‐pole single‐throw switch, and a tunable logic gate, are demonstrated experimentally.
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To meet the requirement of big data era and neuromorphic computations, nonvolatile memory with fast speed, high density, and low power consumption is urgently needed. As an emerging technology, ...phase‐change memory is a promising candidate to solve this problem. However, the drawback of the high power consumption hinders their applications. Most recently, a new phase‐change material of (GeTe)x/(Sb2Te3)yn superlattice attracts intensive attentions owing to its ultralow power consumption comparing with conventional phase‐change memory devices. Many studies on this new material have been reported. However, there still lacks a comprehensive and unified understanding of its atomic picture and working mechanism. This article at first summarizes the broad applications for phase‐change materials. Then, the major progresses of phase‐change superlattices to understand the microscopic structure and working principles for data storage are discussed. Strategies on material optimizations to further enhance device performances are proposed. Finally, an outlook on new applications with these advanced superlattice materials is suggested.
The phase‐change superlattice is an advanced functional material that is suitable for nonvolatile memory with ultralow power consumption, high density, and fast speed. It is a promising candidate for the big data and artificial‐intelligence applications. The major progresses in the field are reviewed including its microscopic picture, working principles, and optimizations. Outlooks on its future development and applications are proposed.
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Flexible smart surfaces with tunable wettability are promising for emerging wearable uses. However, currently, wearable superhydrophobic surfaces with dynamic wetting behaviors are rarely reported. ...Here, a skin‐like superhydrophobic elastomer surface with switchable lotus leaf and rose petal states is reported. Direct laser writing technique is employed for one‐step, programmable, large‐scale fabrication of monolithic and hierarchical micro‐nanostructures on elastomer, leading to strong water repellence. The surface topography can be finely regulated in a rapid and reversible manner by simple stretching, providing the feasibility of controlling the surface wettability by simple body motions. The ability to switch wetting states enables the surface to capture and release multiple droplets in parallel. Furthermore, the active surface can be applied to the joints of fingers and operate as a droplet manipulator under finger motions without requiring energy supply or external appliance. In this work, dynamic tuning of wetting properties is integrated into the design of skin‐like wearable surfaces, revealing great potential in versatile applications such as wearable droplet manipulator, portable actuator, adaptive adhesion control, liquid repellent skin, and smart clothing.
A skin‐like wearable superhydrophobic surface with switchable lotus leaf and rose petal states is reported. One‐step laser processing on a deformable elastomer enables rapid and reversible tailoring of hierarchical structures and wetting properties. The wearable surface can be compliant to finger joints and operates as droplet tweezers under finger motions without energy supply or external appliance.
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Organic single‐crystalline semiconductors with long‐range periodic order have attracted much attention for potential applications in electronic and optoelectronic devices due to their high carrier ...mobility, highly thermal stability, and low impurity content. Molecular doping has been proposed as a valuable strategy for improving the performance of organic semiconductors and semiconductor‐based devices. However, a fundamental understanding of the inherent doping mechanism is still a key challenge impeding its practical application. In this study, solid evidence for the “perfect” substitutional doping mechanism of the stacking mode between the guest and host molecules in organic single‐crystalline semiconductors using polarized photoluminescence spectrum measurements and first‐principles calculations is provided. The molecular host–guest doping is further exploited for efficient color‐tunable and even white organic single‐crystal‐based light‐emitting devices by controlling the doping concentration. The clarification of the molecular doping mechanism in organic single‐crystalline semiconductor host–guest system paves the way for their practical application in high‐performance electronic and optoelectronic devices.
A fundamental understanding of the molecular doping mechanism in organic single‐crystalline semiconductors is provided using polarized PL spectrum measurement and first‐principles calculations. Color‐tunable and white single‐crystal‐based organic light‐emitting devices with high performance are realized, which have important implications for the practical application of organic single‐crystalline semiconductors.
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Natural musculoskeletal systems have been widely recognized as an advanced robotic model for designing robust yet flexible microbots. However, the development of artificial musculoskeletal systems at ...micro-nanoscale currently remains a big challenge, since it requires precise assembly of two or more materials of distinct properties into complex 3D micro/nanostructures. In this study, we report femtosecond laser programmed artificial musculoskeletal systems for prototyping 3D microbots, using relatively stiff SU-8 as the skeleton and pH-responsive protein (bovine serum albumin, BSA) as the smart muscle. To realize the programmable integration of the two materials into a 3D configuration, a successive on-chip two-photon polymerization (TPP) strategy that enables structuring two photosensitive materials sequentially within a predesigned configuration was proposed. As a proof-of-concept, we demonstrate a pH-responsive spider microbot and a 3D smart micro-gripper that enables controllable grabbing and releasing. Our strategy provides a universal protocol for directly printing 3D microbots composed of multiple materials.
Inspired by natural autonomous systems that demonstrate controllable shape, appearance, and actuation under external stimuli, a facile preparation of moisture responsive graphene‐based smart ...actuators by unilateral UV irradiation of graphene oxide (GO) papers is reported. UV irradiation of GO is found to be an effective protocol to trigger the reduction of GO; however, due to the limited light transmittance and thermal relaxation, thick GO paper cannot be fully reduced. Consequently, by tuning the photoreduction gradient, anisotropic GO/reduced GO (RGO) bilayer structure can be easily prepared toward actuation application. To get better control over the responsive properties, GO/RGO bilayer paper with a certain curvature and RGO patterns are successfully prepared for actuator design. As representative examples, smart humidity‐driven graphene actuators that mimic the cilia of respiratory tract and tendril climber plant are successfully developed for controllable objects transport.
A facile preparation of graphene actuators by unilateral UV irradiation of graphene oxide (GO) papers is reported. Anisotropic GO/reduced GO bilayer paper can be directly prepared by controlling the photoreduction gradient. As typical examples, smart humidity‐driven graphene actuators that mimic the cilia of respiratory tract and the tendril climber plant are developed for object transport.
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Muscles and joints make highly coordinated motion, which can be partly mimicked to drive robots or facilitate activities. However, most cases primarily employ actuators enabling simple deformations. ...Therefore, a mature artificial motor system requires many actuators assembled with jointed structures to accomplish complex motions, posing limitations and challenges to the fabrication, integration, and applicability of the system. Here, a holistic artificial muscle with integrated light‐addressable nodes, using one‐step laser printing from a bilayer structure of poly(methyl methacrylate) and graphene oxide compounded with gold nanorods (AuNRs), is reported. Utilizing the synergistic effect of the AuNRs with high plasmonic property and wavelength‐selectivity as well as graphene with good flexibility and thermal conductivity, the artificial muscle can implement full‐function motility without further integration, which is reconfigurable through wavelength‐sensitive light activation. A biomimetic robot and artificial hand are demonstrated, showcasing functionalized control, which is desirable for various applications, from soft robotics to human assists.
A holistic artificial muscle with integrated light‐addressable nodes, using one‐step laser printing from a bilayer structure of poly(methyl methacrylate) and graphene oxide compounded with gold nanorods, is reported. The artificial muscle can implement full‐function motility without further integration, which is reconfigurable through wavelength‐sensitive light activation. A biomimetic robot and artificial hand is demonstrated, showcasing functionalized control, which is desirable for various applications.
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Transient receptor potential melastatin 7 (TRPM7) channel, a calcium‐permeable non‐selective divalent cation channel, is broadly expressed in various cells and tissues, including the brain. TRPM7 is ...thought to be coupled to the metabolic state and regulate calcium homeostasis in the cell. TRPM7 takes part in a wide range of cell biology processes that affect cell growth and proliferation, as well as in embryonic development and skeleton formation. TRPM7 plays a significant role in ischaemic and hypoxic brain injury and neuronal cell death. TRPM7, as a key non‐glutamate mechanism of cerebral ischaemia, also triggers an intracellular ionic imbalance and neuronal cell death in ischaemia and hypoxia. We have reported that TRPM7 is expressed in neurons of the hippocampus and cortex and activation of TRPM7 induced ischaemic neuronal cell death; suppression of TRPM7 with virally mediated gene silencing using siRNA reduced ischaemic neuronal cell death and improved neurobehavioural outcomes in vivo. Recently, we also demonstrated that inhibition of TRPM7 using pharmacological means promoted neuronal outgrowth in vitro and provided neuroprotection against brain injury to hypoxia in vivo. Thus, we have shown the contributions of TRPM7 in many physiological and pathophysiological processes, including hypoxia and ischaemia.
TRPM7, a calcium‐permeable divalent cation channel, is an important player in the non‐glutamate mechanism in stroke and mediates intracellular ionic imbalance and neuronal cell death. Inhibition of TRPM7 reduced neuronal cell death and brain damage in ischaemia and hypoxia.
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Micro/nano optoelectronic devices based on curved substrates play a significant role in the development of wearable devices, electronic skin, conformal sensors, conformal antennas, and soft robots. ...However, the current fabrication processes are oriented toward planar micro/nano devices, and the fabrication of such devices on curved substrates is challenging. Herein, a temperature‐gradient‐assisted nanoimprint‐based in situ micro/nano‐crystal growth method is proposed to fabricate high‐quality curved perovskite microwire crystal (MWC) arrays on curved surfaces. Based on this curved perovskite MWC array without bending‐induced defects, high‐performance curved photodetectors (responsivity = 414 A W−1, detectivity = 1.2 × 1014 Jones, and external quantum efficiency over 140 000%) with extraordinary stability (85% of original performance maintained for more than 2 years) are fabricated to realize a curved imaging device. These results provide insights into the application of high‐performance perovskite photodetectors in nonconformal optical systems.
A temperature gradient‐assisted nanoimprinting method is proposed for the in situ growth of CH3NH3PbBr3 microwire crystal arrays on both developable and non‐developable curved surfaces. The high‐performance photodetector developed based on these bending‐free curved microwire crystals shows extremely high stability, maintaining 85% of its initial performance after being stored in air for more than two years.
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