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With minimal defects, few grain boundaries, and high-performance optoelectronic characteristics, organic semiconductor nanocrystals (OSNCs) have emerged as promising solutions for miniaturized orga...

Bioskins possess a great ability to detect and deliver external mechanical or temperature stimuli into identifiable signals such as color changes. However, the integration of visualization with simultaneous detection of multiple complex external stimuli in a single biosensor device remains a challenge. Here we propose an all-solution-processed bioinspired stretchable electronic skin with interactive color changes and four-mode sensing properties. The fabricated biosensor demonstrates sensitive responses to various stimuli including pressure, strain, voltage, and temperature. Sensing visualization is realized by color changes of the e-skin from brown to green and finally bright yellow as a response to intensified external stimuli, suggesting great application potential in military defense, healthcare monitoring, and smart bionic skin.

Here, biomimetic organic nanocrystals with a butterfly-like morphology (BM) were first constructed from a windmill-like bulky small molecule, T(DAF)3. The BMs possess a peculiar “Janus” feature wit...

To better understand the relationship between the molecular structure and memory characteristics, two carbazole-based organic compounds (Cz-2Ph3F 6FDA and Cz-2TPA 6FDA) with different ratios of electron-donating and electron-withdrawing units were designed and synthesized. An ITO/Cz-2Ph3F 6FDA/Al device was fabricated and presented binary rewritable memory behavior, whereas the as-fabricated ITO/Cz-2TPA 6FDA/Al device exhibited ternary rewritable memory behavior. The electrical conduction behaviors of memory devices were analyzed through theoretical models and experimental data. The molecular simulation indicated that the electrical switching behaviors could be caused by field-induced charge transfer in combination with a conformation change and charge traps. This study provide a practicable strategy to acquired organic molecules with high-performance memory characteristics.

Two-dimensional conjugated microporous polymers (2D CMPs) are sheet/film-like CMPs with amorphous, permanent porous and π-conjugated structures, which have attracted considerable attention over the past few years. Owing to the excellent optoelectronic properties of conjugated polymers together with their microporous, sheet/film-like structures, 2D CMPs have several applications in molecular separation, energy storage, gas sensing, and optoelectronics. This review focuses on the latest advances in fabrication strategies and potential applications of 2D CMPs, with a particular emphasis on optoelectronic device applications. The current challenges and possible future research directions of 2D CMPs are also discussed briefly.

Here, a wide-bandgap organic nanocrystal is constructed from a steric-functionalized difluorene-based organic semiconductor material 2,2′-bi(9,9′-dimethylfluorene) (BMeF). The synthetic nanocrystal presents superior photoelectric integrated properties, with crystallization-enhanced emission and absolute photoluminescence quantum yield (PLQY) up to 75%, high mobility (0.18 cm2 V−1 s−1), and low threshold dual-color lasing behavior from ultraviolet (392 nm) to deep-blue (415 nm). Moreover, organic light-emitting diodes (OLEDs) based on BMeF nanocrystals show deep-blue emission with a brightness of 1152 cd m−2 and turn-on voltage of 2.8 V. This work opens an avenue for high-performance wide-bandgap organic nanocrystals capable of outstanding shortwave emission and high charge mobility.

Electrocatalysis is vital towards the construction of future hydrogen economy, which exerts the critical significance on the macro preparation of nanostructured electrocatalysts. Herein, a fast micro-nano liquid layer induced construction (MLC) strategy is proposed, ensuring a tenfold increase on electrode size with almost negligible heat consumption. As a model-of-concept application, the cations coupled FeOOH nanosheets of thousands of square centimetres are synthesized within 20 minutes at room temperature for water splitting. The density functional theory (DFT) calculations further reveal that the modulation of binary cations (Ni, Zr) leads to the charge accumulation around Fe sites. This results in a more balanced proton adsorption for HER, as well as a lowered energy barrier for OER. As proposed strategy paves a technique for the scaled-up synthesis of nanostructured electrocatalysts, and also provides a platform for exploring more functional nanostructured compounds.

Effective charge separation is essential in plasmon-mediated photochemistry and is usually achieved by constructing plasmon–semiconductor interfaces, which is usually challenging. In this work, by monitoring the plasmon-mediated silver oxidation with in situ Raman spectroscopy, we demonstrate that the adsorbed thiophenol molecules could modulate the rate of photochemical reactions by tuning the charge separation at the plasmon–molecule interfaces. It is found that the thiophenol molecules with strong electron-withdrawing or donating functional groups could accelerate or decelerate the rate of plasmon-mediated silver oxidation, respectively. Owing to the easy tuning of the electronic structures of organic molecules via substitution, our method provides a versatile and convenient approach for the fine modulation of plasmon-mediated photochemical reactions.

Neuromorphic electronics, which use artificial photosensitive synapses, can emulate biological nervous systems with in-memory sensing and computing abilities. Benefiting from multiple intra/interactions and strong light-matter coupling, two-dimensional heterostructures are promising synaptic materials for photonic synapses. Two primary strategies, including chemical vapor deposition and physical stacking, have been developed for layered heterostructures, but large-scale growth control over wet-chemical synthesis with comprehensive efficiency remains elusive. Here we demonstrate an interfacial coassembly heterobilayer films from perylene and graphene oxide (GO) precursors, which are spontaneously formed at the interface, with highly uniform bilayer structure of single-crystal perylene and well-stacked GO over centimeters in size. The planar heterostructure device exhibits an ultrahigh specific detectivity of 5.01×1016 Jones and ultralow energy consumption of 10− 9 W as well as broadband photoperception from 365 to 1550 nm. Moreover, the device shows extraordinary photonic synaptic behaviors with a paired-pulse facilitation (PPF) index of 214% in neuroplasticity, and the heterosynapse array has the capability of information reinforcement learning and recognition.

Effective charge separation is essential in plasmon-mediated photochemistry and is usually achieved by constructing plasmon-semiconductor interfaces, which is usually challenging. In this work, by monitoring the plasmon-mediated silver oxidation with

The facile synthesis of large-area coordination polymer membranes with controlled nanoscale thicknesses is critical towards their applications in information storage electronics. Here, we have reported a facile and substrate-independent interfacial synthesis method for preparing a large-area two-dimensional (2D) coordination polymer membrane at the air–liquid interface. The prepared high-quality 2D membrane could be transferred onto an indium tin oxide (ITO) substrate to construct a nonvolatile memory device, which showed reversible switching with a high ON/OFF current ratio of 103, good stability and a long retention time. Our discovery of resistive switching with nonvolatile bistability based on the substrate-independent growth of the 2D coordination polymer membrane holds significant promise for the development of solution-processable nonvolatile memory devices with a miniaturized device size.

We report the design and preparation of hierarchical hollow-pore nanostructure bilayer conjugated polymer films for high-performance resistive memory devices. By taking the merits of chemical and structural stabilities of a two-dimensional conjugated microporous polymer (2D CMP), a poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) film with a hollow surface was spin-coated onto 2D CMP nanofilm directly, constructing a bilayer heterojunction. A two-terminal diode with a configuration of indium tin oxide/2D CMP/hollow MEH-PPV/Al was fabricated by employing the prepared bilayer heterojunction. The device poses flash feature with a high on/off ratio (>105) and a long retention time (>3.0 × 104 s), which is higher than that of most of the reported conjugated polymers memories. Our work offers a general guideline to construct high on/off ratio polymer memories via hierarchical nanostructure engineering in memristive layer.

MXenes, an emerging class of two-dimensional (2D) transition-metal carbide materials, have received increasing attention for their interesting physiochemical properties. For not only MXenes but also other 2D materials, delamination is a requisite step for the exploitation of their unique properties. In this work, a facile method for exfoliating Ti3C2Tx MXene to nanosheets of small size with the aid of poly(vinylpyrrolidone) (PVP) is designed, which has never been reported to our knowledge. Since both hydrophobic methylene groups and hydrophilic amide groups are provided with PVP, this method is applicable in a wide range of solvents, such as ethanol, water, and chloroform. Considering the charge detrapping and trapping behavior of 2D transition-metal materials in PVP dielectric, a memory device with the configuration of reduced graphene oxide (rGO)/Ti3C2Tx-PVP/Au is directly fabricated with these well-dispersed Ti3C2Tx-PVP composites by the solution process technique. Interestingly, the resultant device exhibits a typical bistable electrical switching, ultralow switching voltage (∼0.9 V), and a nonvolatile rewritable memory effect with the function of flash. This work might pave the way of using MXenes for future data storage, which is an indispensable field nowadays.

The rising and huge demand for light conversion materials in versatile applications has led to extensive research on eco-friendly phosphors from an economic and environmental perspective. However, ...

Building stretchable memory is an effective strategy for developing next-generation memory technologies toward stretchable and wearable electronics. Here we demonstrate a universal strategy for the fabrication of high performance stretchable polymer memory via tailoring surface morphology, in which common conjugated polymers and sharp reduced graphene oxide (r-rGO) films are used as active memristive layers and conductive electrodes, respectively. The fabricated devices feature write-once-read-many-times (WORM) memory, with a low switching voltage of 1.1 V, high ON/OFF current ratio of 104, and an ideal long retention time over 12000 s. Sharp surface-induced resistive switching behavior has been proposed to explore the electrical transition. Moreover, the polymer memory show reliable electrical bistable properties with a stretchability up to 30%, demonstrating their great potential candidates as high performance stretchable memory in soft electronics.

The activity and stability of Cu nanostructures strongly depend on their sizes, morphology and structures. Here we report the preparation of two-dimensional (2D) Cu@Cu-BTC core-shell nanosheets (NSs). The thickness of the Cu NSs could be tuned to sub-10 nm through a mild etching process, in which the Cu-BTC in situ grow along with the oxidation on the surface of the Cu NSs. This unique strategy can also be extended to synthesize one-dimensional (1D) Cu@Cu-BTC nanowires (NWs). Furthermore, the obtained Cu@Cu-BTC NSs could be applied as an effective material to the memory device with the write-once-read-many times (WORM) behavior and the high ION/IOFF ratio (>2.7 × 103).

Flexible electronics is an interdisciplinary research field. By employing the intrinsically soft materials, the resulting devices feature outstanding mechanical flexibility and conformability, and expected lightweight configuration, functional reconfigurability, large-area compatibility. Here we explore the current status, including materials, fabrication and applications, of flexible electronics from intrinsically soft materials. The future applications and challenges of this pervading technology are also considered.

Inspired by the 2D bilayer lipid membranes in nature, a unique supramolecular "push-pull" synergetic strategy toward self-assembled 2D organic crystals (2DOCs) is proposed in this work, which can effectively suppress the interlayer 3D stacking while maintaining the assembly of the intralayer for 2D growth. For this purpose, a model molecule PF-Py consisting of a planar supramolecular "attractor" and a nonplanar steric "repellor" is designed for the solution self-assembly process. Well-defined 2DOCs including crystal nanosheets and millimeter-sized crystal films with layered amphiphile-like packing are obtained, which is analogical to the cell membranes of living organisms. Thanks to the special packing mode, the 2DOCs have fascinating integrated photoelectric property, with high mobility of 7.8 × 10-2 cm2 V-1 s-1 , high crystalline state photoluminescence quantum yield of 55%, and superior deep-blue laser characteristics with a low threshold of 5.51 µJ cm-2 . This supramolecular synergetic strategy advances the design of 2D organic semiconductor crystals for high performance optoelectronics.

Room temperature phosphorescent (RTP) materials are rising and gaining considerable attention due to their special photo-capture–release ability. Herein, a kind of environmentally friendly RTP composite was devised by microwaving a mixture of carbon dots, boric acid, and urea, in the presence of covalent bonds and hydrogen bonds between each of the components. The resultant RTP material showed ultra-long phosphorescence lifetime up to 1005.6 ms with an outstanding afterglow as long as 9.0 s. Moreover, this afterglow feature with moisture sensitive behavior was explored to achieve multilevel anti-counterfeiting, with the function of complex decryption of encrypted secret information under multiple stimuli. Our results provide a green strategy for scalable synthesis of carbon-based RTP materials, and extend their application scope to high level information security.

Electronic textiles (e-textiles) typically comprise fabric substrates with electronic components capable of heating, sensing, lighting and data storage. In this work, we rationally designed and fabricated anisotropic light/thermal emitting e-textiles with great mechanical stability based on a sandwich-structured tri-electrode device. By coating silver nanowire network/thermal insulation bilayer on fabrics, an anisotropic thermal emitter can be realized for smart heat management. By further covering the emissive film and the top electrode on the bilayer, light emitters with desirable patterns and colors are extracted from the top surface via an alternative current derived electroluminescence. Both the light and thermal emitting functions can be operated simultaneously or separately. Particularly, our textiles exhibit reliable heating and lighting performance in water, revealing excellent waterproof feature and washing stability.

Biocompatible materials have received increasing attention as one of the most important building blocks for flexible and transient memories. Herein, a fully biocompatible resistive switching (RS) memory electronic composed of a carbon dot (CD)-polyvinyl pyrrolidone (PVP) nanocomposite and a silver nanowire (Ag NW) network buried in a flexible gelatin film is introduced with promising nonvolatile RS characteristics for flexible and transient memory applications. The fabricated device exhibited a rewritable flash-type memory behavior, such as low operation voltage (≈-1.12 V), high ON/OFF ratio (>102), long retention time (over 104 s), and small bending radius (15 mm). As a proof of degradability, this transient memory can dissolve completely within 90 s after being immersed into deionized water at 55 °C; it can decompose naturally in soil within 6 days. This fully biocompatible memory electronic paves a novel way for flexible and wearable green electronics.

In order to further study the conserved quantity of the mechanical system based on the fractional order model, this paper applies the integral factor method to the fractional order Lagrange system, and establishes a new method to find the conserved quantity of the Lagrange system under the fractional order model. Firstly, the necessary conditions for the existence of conserved quantity in fractional Lagrange system and the relationship between the integral factor and the conserved quantity are found. Secondly, the fractional generalized killing equation for determining the integral factor is defined and given. Finally, the conserved quantity of Lagrange system based on fractional order model is obtained. At the end of the paper, an example is given to illustrate the application of the results.

Suppressing the operating current in resistive memory devices is an effective strategy to minimize their power consumption. Herein, we present an intrinsic low-current memory based on two-dimensional (2D) hybrid heterostructures consisting of partly reduced graphene oxide (p-rGO) and conjugated microporous polymer (CMP) with the merits of being solution-processed, large-scale, and well patterned. The device with the heterostructure of p-rGO/CMP sandwiched between highly reduced graphene oxide (h-rGO) and aluminum electrodes exhibited rewritable and nonvolatile memory behavior with an ultralow operating current (∼1 μA) and efficient power consumption (∼2.9 μW). Moreover, the on/off current ratio is over 103, and the retention time is up to 8 × 103 s, indicating the low misreading rate and high stability of data storage. So far, the value of power is about 10 times lower than those of the previous GO-based memories. The bilayer architecture provides a promising approach to construct intrinsic low-power resistive memory devices.