Mechanochromic Photonic Vitrimer Thermal Management Device Based on Dynamic Covalent Bond

Flexible self-healing thermal management devices are increasingly in demand due to their high flexibility, low driving voltage, and excellent stability of thermal property. In this paper, the design of mechanochromic self-healing thermal management devices is reported based on photonic vitrimer through self-healing dynamic covalent bond. A series of new photonic vitrimers i first prepared by dynamic disulfide covalent bond and PS@SiO₂ photonic crystals. The resulting photonic vitrimer exhibits bright structural colors, large tensile strain (>1000%), high mechanical strength (>10 MPa) and self-healing ability (>95% efficiency). More importantly, the structural color remains constant after 10000 stretching/releasing cycles, demonstrating excellent mechanical stability, creep-resistance, and durability. Taking advantage of the above features, a novel mechanochromic flexible wireless thermal management (MFW) device is developed by semi-embedding the photonic vitrimer in a thermally conductive carbon nanotube film and then integrating it with a Bluetooth module and a control chip. Interestingly, the MFW device exhibits mechanochromic property, fast thermal response, low driving voltage (103 °C, at 3 V), and precise temperature control. Notably, the device even remains electrothermal performance (105 °C) after self-healing. This work provides new insight into the self-healing photonic materials, and the device shows promising applications in wearable electronics, vitro physiotherapy, and personal heating.     

Flexible and Stretchable Smart Display: Materials,Fabrication, Device Design,and System Integration

Recent technological advances in nanomaterials have driven the development of high‐performance light‐emitting devices with flexible and stretchable form factors. Deformability in such devices is mainly achieved by replacing the rigid materials in the device components with flexible nanomaterials and their assemblies (e.g., carbon nanotubes, silver nanowires, graphene, and quantum dots) or with intrinsically soft materials and their composites (e.g., polymers and elastomers). Downscaling the dimensions of the functional materials to the nanometer range dramatically decreases their flexural rigidity, and production of polymer/elastomer composites with functional nanomaterials provides light‐emitting devices with flexibility and stretchability. Furthermore, monolithic integration of these light‐emitting devices with deformable sensors furnishes the resulting display with various smart functions such as force/capacitive touch‐based data input, personalized health monitoring, and interactive human–machine interfacing. These ultrathin, lightweight, and deformable smart optoelectronic devices have attracted widespread interest from materials scientists and device engineers. Here, a comprehensive review of recent progress concerning these flexible and stretchable smart displays is presented with a focus on materials development, fabrication techniques, and device designs. Brief overviews of an integrated system of advanced smart displays and cutting‐edge wearable sensors are also presented, and, to conclude, a discussion of the future research outlook is given.     

Wearable,Human‐Interactive,Health‐Monitoring,Wireless Devices Fabricated by Macroscale Printing Techniques

Wearable human‐interactive devices are advanced technologies that will improve the comfort, convenience, and security of humans, and have a wide range of applications from robotics to clinical health monitoring. In this study, a fully printed wearable human‐interactive device called a “smart bandage” is proposed as the first proof of concept. The device incorporates touch and temperature sensors to monitor health, a drug‐delivery system to improve health, and a wireless coil to detect touch. The sensors, microelectromechanical systems (MEMS) structure, and wireless coil are monolithically integrated onto flexible substrates. A smart bandage is demonstrated on a human arm. These types of wearable human‐interactive devices represent a promising platform not only for interactive devices, but also for flexible MEMS technology.     

Light Management with Patterned Micro‐ and Nanostructure Arrays for Photocatalysis,Photovoltaics, and Optoelectronic and Optical Devices

The design and fabrication of patterned micro‐ and nanostructure arrays have been demonstrated to be a powerful strategy toward efficient light management, which is of vital importance to a variety of photon‐related applications such as photocatalysis, photovoltaics, optoelectronic devices, and optical devices. Tunable optical reflectance, scattering, transmittance, and absorption can be readily achieved by adjusting the characteristics of the primary units in the micro‐/nanoarrays and the spatial patterns of the aligned units, thus realizing controllable light–matter interactions. This review describes various light management strategies based on patterned micro‐/nanoarrays, such as scattering enhancement, antireflection, resonances, photonic crystals, and plasmonic structures. Furthermore, recent advances in the applications of patterned micro‐/nanoarrays in photoelectrochemical water splitting, solar cells, photodetectors, light emitting diodes, lasers, color display, microlens arrays, and photonic crystal sensors are summarized, with particular attention paid to the light management mechanisms and the relationship between the structure and device performance. Lastly, the prospects and existing challenges facing the development of the photon‐related applications based on patterned micro‐/nanoarrays are discussed.     

Synergistic Toughening and Self-Healing Strategy for Highly Efficient and Stable Flexible Perovskite Solar Cells

Halide perovskites are qualified to meet the flexibility demands of optoelectronic field because of their merits of flexibility, lightness, and low cost. However, the intrinsic defects and deformation-induced ductile fracture in both perovskite and buried interface significantly restrict the photoelectric performance and longevity of flexible perovskite solar cells (PVSCs). Here, a dual-dynamic cross-linking network is schemed to boost the photovoltaic efficiency and mechanical stability of flexible PVSCs by incorporating natural polymerizable small molecule α-lipoic acid (LA). The LA therein can be autonomously ring-opening polymerized through dynamic disulfide bonds and hydrogen bonds, concurrently forming coordination bonds to interact with perovskite component. Importantly, the polymerization product can serve as efficacious passivating and toughening agents to simultaneously optimize interfacial contact, enhance perovskite crystallinity and sustain robust mechanical bendability. Subsequently, the rigid (or flexible) p-i-n device realizes a champion efficiency of 22.43% (or 19.03%) with prominent operational stability. Moreover, the dual-dynamic cross-linking network endows PVSCs with bendability and self-healing capacity, allowing the optimized devices to retain >80% efficiency after 3000 bending cycles, and subsequently restore to ≈95% of its initial efficiency under mild heat-treatment. This toughening and self-healing strategy provides a facile and efficient path to prolong operational lifetime of flexible device.     

Soft Human–Machine Interface with Triboelectric Patterns and Archimedes Spiral Electrodes for Enhanced Motion Detection

The rapid development of electronic skins has allowed novel multifunctional human–machine interaction interfaces, especially in motion interaction sensors. Although motion sensing is widely used in advanced flexible electronic devices through the integration of single sensing units, the number of electrodes has increased with the increase in integration by the square multiple. This paper presents a self-powered electronic skin based on the Archimedes spiral structure design, which can detect the multi-directional movement of the slider without external energy supply. As the rotation angle of the Archimedes spiral increases from 2π to 4π, the maximum resolvable movement direction of the device increases from 24 to 280, and the number of electrodes is kept at 4. Through the exploration of the principle of triboelectricity, the inherent electronegativity of the triboelectric materials is used as the basis for signal discrimination, which not only increases the reliability of the device, but also solves the problem of energy supply during device operation. A reduced number of electrodes and its battery-free nature enables this electronic skin to be easily integrated into portable electronic devices, such as laptops, smart phones, healthcare devices, etc.     

Self-Healable Triboelectric Nanogenerators: Marriage between Self-Healing Polymer Chemistry and Triboelectric Devices

Based on the triboelectrification and electrostatic induction coupling, triboelectric nanogenerators (TENGs) can convert mechanical energy into electrical energy, showing a promising potential in the fields of micro/nano energy and self-powered sensors applications. However, the devices are prone to malfunction due to fatigue and damage, limiting their development and applications. In this review, according to the working modes and operational malfunctions as well as the possible solutions, it is proposed that a robust TENG device can be constructed from three perspectives: self-healing friction layers, self-healing electrodes, and self-healing whole devices. Based on the structure, suitable environment, and self-healing materials, the design ideas and fabrication approaches of self-healing TENGs in recent years are summarized in detail. Finally, the development of self-healing TENGs in energy harvesting and self-powered sensors is outlined. It is the wish to provide insights and guidance for the application design of self-healing TENGs in the future.     

一种新型结构的InGaP/GaAs负阻异质结晶体管

利用硅双基区晶体管（DUBAT）产生负阻的原理,针对HBT器件结构和MBE材料结构的特点,设计并研制出一种基区刻断结构的负阻型HBT (NDRHBT) . 经过特性和参数测试,证明此种NDRHBT具有显著的微分负阻效应,并发现负电流区负阻效应和光照可改变其I-V特性,器件模拟结果和测试结果基本一致.     

能带混合量子阱与异质谷间转移电子器件研究

介绍了能带混合量子阱中的多能谷混合和异质谷间转移电子效应。运用这一新物理效应设计制成了新的异质谷间转移电子器件。给出了器件连续波和脉冲工作时的射频振荡特性。使用多能谷有效质量理论和ＭｏｎｔｅＣａｒｌｏ模拟方法模拟计算了器件直流和射频工作状态下的电子运动过程。提出了新的器件射频工作模式。最后讨论了能带理论研究在新器件开发中的重要作用和用能带理论研究设计器件的方法     

Direct Laser Writing of Superhydrophobic PDMS Elastomers for Controllable Manipulation via Marangoni Effect

Direct light‐to‐work conversion enables manipulating remote devices in a contactless, controllable, and continuous manner. Although some pioneering works have already proven the feasibility of controlling devices through light‐irradiation‐induced surface tension gradients, challenges remain, including the flexible integration of efficient photothermal materials, multifunctional structure design, and fluidic drag reduction. This paper reports a facile one‐step method for preparing light‐driven floating devices with functional surfaces for both light absorption and drag reduction. The direct laser writing technique is employed for both arbitrary patterning and surface modification. By integrating the functional layer at the desired position or by designing asymmetric structures, three typical light‐driven floating devices with fast linear or rotational motions are demonstrated. Furthermore, these devices can be driven by a variety of light sources including sunlight, a filament lamp, or laser beams. The approach provides a simple, green, and cost‐effective strategy for building functional floating devices and smart light‐driven actuators.     

Touch‐Interactive Flexible Sustainable Energy Harvester and Self‐Powered Smart Card

Sustainable and safe energy sources combined with cost effectiveness are major goals for society when considering the current scenario of mass production of portable and Internet of Things (IoT) devices along with the huge amount of inevitable e‐waste. The conceptual design of a self‐powered “eco‐energy” smart card based on paper promotes green and clean energy, which will bring the zero e‐waste challenge one step closer to fruition. A commercial raw filter paper is modified through a fast in situ functionalization method, resulting in a conductive cellulose fiber/polyaniline composite, which is then applied as an energy harvester based on a mechano‐responsive charge transfer mechanism through a metal/conducting polymer interface. Different electrodes are studied to optimize charge transfer based on contact energy level differences. The highest power density and current density obtained from such a paper‐based “eco‐energy” smart card device are 1.75 W m^?2 and 33.5 mA m^?2 respectively. This self‐powered smart energy card is also able to light up several commercial light‐emitting diodes, power on electronic devices, and charge capacitors.     

An Assistive VLC Technology for Smart Home Devices Using EOG

In recent years, assistive technology has been an emerging area of research to improve the quality of life, especially for the disabled and elderly people. In this paper, a novel electro-oculogram (EOG) signal based assistive visible light communication (VLC) in a smart home environment is presented. The eye movement is captured using silver chloride (AgCl) surface electrodes placed around eyes. The captured signal is further processed and transmitted using a VLC link to control smart home devices. To validate the proposed EOG-VLC based smart device control scheme, experiments were conducted. For the ease of the experiments, instead of an actual smart home device, we employed a digital door lock to verify its accurate control operation. Experiment results demonstrate that the proposed smart device control scheme operates accurately and reliably. Therefore, since the proposed scheme is based on a less hazardous VLC link, it is envisioned that the scheme can pave the way for greener and safer smart homes, particularly benefiting disabled and elderly people.     

Microstructured Actuation of Liquid Crystal Polymer Networks

Smart microstructured materials enable functions such as actuation, detection, transportation, and sensing with potential applications ranging from robotics and photonics to biomedical devices. Of the many materials systems, liquid crystal polymer networks (LCN) are fascinating owing to their ability to exhibit reversible macroscopic deformation driven by a molecular order–disorder phase transition. LCN have been increasingly explored for their utility in the design and fabrication of smart actuating devices capable of complex shape changes or motions upon external stimulation of humidity, heat, light, and other stimuli, and recent studies in this field show that their actuation complexity can be enriched and actuation performance enhanced by having some sort of microstructures. Herein, the recent progress in microstructured actuation of LCN materials with substructures in scale ranging from micrometer to millimeter is reported, placing the emphasis on the main approaches to generating a microstructure in LCN, which include patterned LC director fields, patterned chain crosslinking in LCN with uniaxial orientation of mesogens, 3D/4D printing, and replica molding. The potential applications in microstructured 3D actuators and devices as well as functional LCN surfaces are also highlighted, with an outlook on important issues and future trends in smart microstructured LCN materials and actuators.     

Light‐Emitting Devices Based on Electrochemiluminescence Gels

Electrochemiluminescence (ECL) is a self‐emission of light from electrochemically excited luminophores via a series of redox reactions. Over the past decade, light‐emitting devices based on gel‐phase ECL active materials, i.e., gel electrolyte composites (referred to as ECL gels) containing an ECL luminophore, electrolyte, and network matrix, have attracted considerable attention as a complementary device platform to conventional electroluminescent devices for low‐cost printable displays and solid‐state light sources. Although the ECL phenomenon is extensively exploited in analytical diagnostics and sensing, the development of printable and fast‐response gel‐type luminescent materials may further expand the potential application of ECL in solid‐state flexible, bendable, and stretchable light‐emitting devices. This review summarizes the operation mechanisms of ECL‐based light‐emitting devices, ECL emitters and electrolytes, engineering strategies for obtaining printable high‐strength/high‐conductivity ECL gels, and emerging applications of gel‐type ECL devices.     

Power-Free Contact Lens for Glucose Sensing

Recent advances in wearable devices have enabled noninvasive monitoring for healthcare applications. Smart contact lenses have gained substantial attention for medical diagnosis through the analysis of vital signs in tear fluids. However, previous studies have mostly focused on designs embedded with electronic devices or antennas for wireless transmission, which are power-intensive and require external receivers around the ocular system. Here, the study reports a power-free smart contact lens for noninvasive glucose sensing according to the color changes of multiple electrochromic electrodes to achieve direct data transmission without the external wireless system. The device detects various glucose concentrations, from the ordinary range (0.16–0.5 mm ) to abnormally high concentrations (0.9 mm ). The multi-electrode design exhibits acceptable accuracy, with a correlation coefficient r = 0.99543 to the controlled sample and allowed low-glucose detections with concentrations down to 0.05 mm . The device shows good reproducibility, with standard deviations of determined glucose levels of 0.0462 and 0.025 for four continuous cycles and for an interval of several days, respectively. It is believed that the reported smart contact lens has the potential for daily health monitoring by ordinary users without a power supply and external devices. Its simple electronics-free structure will allow for immediate application to the market with cost-effective manufacturing.     

Remotely Controlled Red Blood Cell Carriers for Cancer Targeting and Near‐Infrared Light‐Triggered Drug Release in Combined Photothermal–Chemotherapy

Red blood cells (RBCs), the “innate carriers” in blood vessels, are gifted with many unique advantages in drug transportation over synthetic drug delivery systems (DDSs). Herein, a tumor angiogenesis targeting, light stimulus‐responsive, RBC‐based DDS is developed by incorporating various functional components within the RBC platform. An albumin bound near‐infrared (NIR) dye, together with a chemotherapy drug doxorubicin, is encapsulated inside RBCs, the surfaces of which are modified with a targeting peptide to allow cancer targeting. Under stimulation by an external NIR laser, the membrane of the RBCs would be destroyed by the light‐induced photothermal heating, resulting in effective drug release. As a proof of principle, RBC‐based cancer cell targeted drug delivery and light‐controlled drug release is demonstrated in vitro, achieving a marked synergistic therapeutic effect through the combined photothermal–chemotherapy. This work presents a novel design of smart RBC carriers, which are inherently biocompatible, promising for targeted combination therapy of cancer.     

国外几种半导体新器件的发展概况

本文对一些半导体新器件,如HEMT、HBT、超晶格器件、约瑟夫逊器件、三维器件等,的工作原理,器件结构,工艺技术,器件水平和应用前景进行了评述。     

Photonic Vitrimer Elastomer with Self-Healing,High Toughness,Mechanochromism, and Excellent Durability based on Dynamic Covalent Bond

Vitrimers, with their unique dynamic covalent bonds, possess attractive self-healability and mechanical robustness, providing an intriguing opportunity to construct functional soft materials. However, their potential for function recovery, especially optical function, is underexplored. Harnessing the synergistic effect of photonic crystals and vitrimers, a novel photonic vitrimer with light regulating and self-healing capabilities is presented. The resulting photonic vitrimer exhibits a large tensile strain (>1000%), high toughness (21.2 kJ m⁻³), bright structural color, and mechanochromism. Notably, the structural color remains constant even after 10 000 stretching/releasing cycles, showing superior mechanical stability, creep-resistance, and excellent durability. More importantly, the exchange of dynamic covalent bonds imparts the photonic vitrimer with a self-healing ability (>95% efficiency), enabling the recovery of its optical function. Benefiting from the above merits, the photonic vitrimer has been successfully used as a sensor for human motion detection, which demonstrates visualized interactive sensibility even after self-repairing. This material design provides a general strategy for optical functionalization of vitrimers. The photonic vitrimer elastomers present great potential as resilient functional soft materials for diverse flexible devices and a novel optical platform for soft robotics, smart wearable devices, and human-machine interaction.     

High-Throughput Screening of Self-Healable Polysulfobetaine Hydrogels and their Applications in Flexible Electronics

Hydrogels are promising materials in the applications of wound adhesives, wearable electronics, tissue engineering, implantable electronics, etc. The properties of a hydrogel rely strongly on its composition. However, the optimization of hydrogel properties has been a big challenge as increasing numbers of components are added to enhance and synergize its mechanical, biomedical, electrical, and self-healable properties. Here in this work, it is shown that high-throughput screening can efficiently and systematically explore the effects of multiple components (at least eight) on the properties of polysulfobetaine hydrogels, as well as provide a useful database for diverse applications. The optimized polysulfobetaine hydrogels that exhibit outstanding self-healing and mechanical properties, have been obtained by high-throughput screening. By compositing with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), intrinsically self-healable and stretchable conductors are achieved. It is further demonstrated that a polysulfobetaine hydrogel-based electronic skin, which exhibits exceptionally fast self-healing capability of the whole device at ambient conditions. This work successfully extends high-throughput synthetic methodology to the field of hydrogel electronics, as well as demonstrates new directions of healable flexible electronic devices in terms of material development and device design.     

A Sensing and Stretchable Polymer-Dispersed Liquid Crystal Device Based on Spiderweb-Inspired Silver Nanowires-Micromesh Transparent Electrode

Polymer-dispersed liquid crystal (PDLC) devices are truly promising optical modulators for information display, smart window as well as intelligent photoelectronic applications due to their fast switching, large optical modulation as well as cost-effectiveness. However, realizing highly soft PDLC devices with sensing function remains a grand challenge because of the intrinsic brittleness of traditional transparent conductive electrodes. Here, inspired by spiderweb configuration, a novel type of silver nanowires (AgNWs) micromesh-based stretchable transparent conductive electrodes (STCEs) is developed to support the realization of soft PDLC device. Benefiting from the embedding design of AgNWs micromesh in polydimethylsiloxane (PDMS), the STCEs can maintain excellent electrical conductivity and transparency even in various extreme conditions such as bending, folding, twisting, stretching as well as multiple chemical corrosion. Further, STCEs with the embedded AgNWs micromesh endow the assembled PDLC device with excellent photoelectrical properties including rapid switching speed (<1 s), large optical modulation (69% at 600 nm), as well as robust mechanical stability (bending over 1000 cycles and stretching to 40%). Moreover, the device displays the pressure sensing function with high sensitivity in response to pressure stimulus. It is conceivable that AgNWs micromesh transparent electrodes will shape the next generation of related soft smart electronics.