Solution-Processed Polymer Memcapacitors with Stimulus-Controlled and Evolvable Synaptic Functionalities: From Short-Term Plasticity to Long-Term Plasticity to Metaplasticity.

In the vanguard of neuromorphic engineering, we develop a paradigm of biocompatible polymer memcapacitors using a seamless solution process, unleashing comprehensive synaptic capabilities depending on both the stimulation form and history. Like the human brain to learn and adapt, the memcapacitors exhibit analogue-type and evolvable capacitance shifts that mirror the complex flexibility of synaptic strengthening and weakening. With increasing frequency and intensity of the stimulation, the memcapacitors demonstrate an evolution from short-term plasticity (STP) to long-term plasticity (LTP), and even to metaplasticity (MP) at a higher level.

Direct Selective Epitaxy of 2D SbTe onto Monolayer WS for Vertical p-n Heterojunction Photodetectors.

Two-dimensional transition metal dichalcogenides (2D-TMDs) possess appropriate bandgaps and interact via van der Waals (vdW) forces between layers, effectively overcoming lattice compatibility challenges inherent in traditional heterojunctions. This property facilitates the creation of heterojunctions with customizable bandgap alignments. However, the prevailing method for creating heterojunctions with 2D-TMDs relies on the low-efficiency technique of mechanical exfoliation.

Long-range order enabled stability in quantum dot light-emitting diodes.

Light-emitting diodes (LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiencies (EQEs) of more than 25% with narrowband emission, but these LEDs have limited operating lifetimes. We posit that poor long-range ordering in perovskite QD films-variations in dot size, surface ligand density and dot-to-dot stacking-inhibits carrier injection, resulting in inferior operating stability because of the large bias required to produce emission in these LEDs. Here we report a chemical treatment to improve the long-range order of perovskite QD films: the diffraction intensity from the repeating QD units increases three-fold compared with that of controls.

Conductive MXene/Polymer Composites for Transparent Flexible Supercapacitors.

Transparent flexible energy storage devices are limited by the trade-off among flexibility, transparency, and charge storage capability of their electrode materials. Conductive polymers are intrinsically flexible, but limited by small capacitance. Pseudocapacitive MXene provides high capacitance, yet their opaque and brittle nature hinders their flexibility and transparency.

Voltage-Mode Ferroelectric Synapse for Neuromorphic Computing.

Ferroelectric materials with a modulable polarization extent hold promise for exploring voltage-driven neuromorphic hardware, in which direct current flow can be minimized. Utilizing a single active layer of an insulating ferroelectric polymer, we developed a voltage-mode ferroelectric synapse that can continuously and reversibly update its states. The device states are straightforwardly manifested in the form of variable output voltage, enabling large-scale direct cascading of multiple ferroelectric synapses to build a deep physical neural network.

RegEMR: a natural language processing system to automatically identify premature ovarian decline from Chinese electronic medical records.

Background: The ovarian reserve is a reservoir for reproductive potential. In clinical practice, early detection and treatment of premature ovarian decline characterized by abnormal ovarian reserve tests is regarded as a critical measure to prevent infertility. However, the relevant data are typically stored in an unstructured format in a hospital's electronic medical record (EMR) system, and their retrieval requires tedious manual abstraction by domain experts.

Inkjet-printed h-BN memristors for hardware security.

Inkjet printing electronics is a growing market that reached 7.8 billion USD in 2020 and that is expected to grow to ∼23 billion USD by 2026, driven by applications like displays, photovoltaics, lighting, and radiofrequency identification. Incorporating two-dimensional (2D) materials into this technology could further enhance the properties of the existing devices and/or circuits, as well as enable the development of new concept applications.

Reducing Contact Resistance in Organic Field-Effect Transistors: A Comprehensive Comparison between 2D and Microrod Single Crystals.

A comprehensive comparison of organic single crystals based on a single material but with different dimensions provides a unique approach to probe their carrier injection mechanism. In this report, both two-dimensional (2D) and microrod single crystals with the same crystalline structure of an identical thiopyran derivative, 7,14-dioctylnaphtho[2,1-:6,5-']bis(cyclopentane[]thiopyran) (C-SS), are grown on a glycerol surface with the space-confined method. Organic field-effect transistors (OFETs) based on the 2D C-SS single crystal exhibit superior performance compared with those based on the microrod single crystal, particularly in their contact resistance ().

Breaking the Size Limitation of Directly-Synthesized PbS Quantum Dot Inks Toward Efficient Short-wavelength Infrared Optoelectronic Applications.

PbS quantum dots (QDs) are promising building blocks for solution-processed short-wavelength infrared (SWIR) devices. The recently developed direct synthesis of semi-conductive PbS QD inks has substantially simplified the preparation processing and reduced the material cost, while facing the challenge to synthesize large-size QDs with absorption covering the SWIR region. Herein, we for the first time realize a low-cost, scalable synthesis of SWIR PbS QD inks after an extensive investigation of the reaction kinetics.

ZnO nanowire optoelectronic synapse for neuromorphic computing.

Artificial synapses that integrate functions of sensing, memory and computing are highly desired for developing brain-inspired neuromorphic hardware. In this work, an optoelectronic synapse based on the ZnO nanowire (NW) transistor is achieved, which can be used to emulate both the short-term and long-term synaptic plasticity. Synaptic potentiation is present when the device is stimulated by light pulses, arising from the light-induced Odesorption and the persistent photoconductivity behavior of the ZnO NW.

Amine-Assisted Delaminated 2D TiCT MXenes for High Specific Capacitance in Neutral Aqueous Electrolytes.

Electrochemical capacitors using neutral aqueous electrolytes are safer and cheaper and allow diverse current collectors compared with the counterparts using organic or acidic/alkaline electrolytes. Two-dimensional (2D) MXenes have been demonstrated as the high-capacitive materials with high rate performance. However, MXene electrodes often exhibit a limited capacitance in neutral electrolytes, where the reversible electrochemical reactions rely greatly on the structural and surface properties of MXenes depending on their synthesis methods.

Conducting polymer-inorganic nanocomposite-based gas sensors: a review.

With the rapid development of conductive polymers, they have shown great potential in room-temperature chemical gas detection, as their electrical conductivity can be changed upon exposure to oxidative or reductive gas molecules at room temperature. However, due to their relatively low conductivity and high affinity toward volatile organic compounds and water molecules, they always exhibit low sensitivity, poor stability, and gas selectivity, which hinder their practical gas sensor applications. In addition, inorganic sensitive materials show totally different advantages in gas sensors, such as high sensitivity, fast response to low concentration analytes, high surface area, and versatile surface chemistry, which could complement the conducting polymers in terms of the sensing characteristics.

Toward Broadband Imaging: Surface-Engineered PbS Quantum Dot/Perovskite Composite Integrated Ultrasensitive Photodetectors.

PbS colloidal quantum dots passivated by the thiocyanate anion (SCN) are developed to combine with perovskite (CHNHPbI) as building blocks for UV-vis-NIR broadband photodetectors. Both high electrical conductivity and appropriate energy-level alignment are obtained by the in situ ligand exchange with SCN. The PbS-SCN/CHNHPbI composite photodetectors are sensitive to a broad wavelength range covering the UV-vis-NIR region (365-1550 nm), possessing an excellent responsivity of 255 A W at 365 nm and 1.

Filter-Free Selective Light Monitoring by Organic Field-Effect Transistor Memories with a Tunable Blend Charge-Trapping Layer.

Integration of selective photodetection and signal storage in a single device, such as organic field-effect transistor (OFET) memories, meets the demands for radiation monitoring and protection. A new strategy is developed to achieve filter-free and selective light monitoring by adopting a solution-processed blend charge-trapping layer in OFET memories, where the charge-trapping layer is composed of phenyl-C-butyric acid methyl ester (PCBM) dispersed in a polymer electret thin film. The OFET memory without PCBM shows response only to ultraviolet light, whereas the spectral response edges are extended to the visible and near-infrared regions in the corresponding devices with relatively low and high contents of PCBM in the charge-trapping layer, respectively.

Ionic-liquid-assisted one-pot synthesis of CuO nanoparticles/multi-walled carbon nanotube nanocomposite for high-performance asymmetric supercapacitors.

Finding earth-abundant and high-performance electrode materials for supercapacitors is a demanding challenge in the energy storage field. Cuprous oxide (CuO) has attracted increasing attention due to its theoretically high specific capacitance, however, the development of CuO-based electrodes with superior capacitive performance is still challenging. We herein report a simple and effective ionic-liquid-assisted sputtering approach to synthesizing the CuO nanoparticles/multi-walled carbon nanotubes (CuO/MWCNTs) nanocomposite for high-performance asymmetric supercapacitors.

Fullerene derivatives act as inhibitors of leukocyte common antigen based on molecular dynamics simulations.

Fullerene-based molecules are being studied as potential inhibitors of protein tyrosine phosphatases due to their unique properties and low toxicity. However, the underlying molecular mechanism remains elusive. In this study, molecular dynamics (MD) simulations in conjunction with molecular docking calculations were utilized to investigate the binding effects of C, C(NH), and C(OH) on the enzymatic activity of CD45 (a receptor-like protein tyrosine phosphatase).

Aggregated Single-Walled Carbon Nanotubes Absorb and Deform Dopamine-Related Proteins Based on Molecular Dynamics Simulations.

Single-walled carbon nanotubes (SWCNTs) have attracted considerable attention owing to their applications in various fields such as biotechnology and biomedicine. Recently, aggregated SWCNTs have shown more significant effects on the treatment of methamphetamine addiction (Nat. Nanotech.

Embedded Ag Grid Electrodes as Current Collector for Ultraflexible Transparent Solid-State Supercapacitor.

Flexible transparent solid-state supercapacitors have attracted immerse attention for the power supply of next-generation flexible "see-through" or "invisible" electronics. For fabrication of such devices, high-performance flexible transparent current collectors are highly desired. In this paper, the utilization of embedded Ag grid transparent conductive electrodes (TCEs) fabricated by a facile soft ultraviolet imprinting lithography method combined with scrap techniques, as the current collector for flexible transparent solid-state supercapacitors, is demonstrated.

Efficient and Reversible Electron Doping of Semiconductor-Enriched Single-Walled Carbon Nanotubes by Using Decamethylcobaltocene.

Single-walled carbon nanotubes (SWCNTs) offer great potential for field-effect transistors and integrated circuit applications due to their extraordinary electrical properties. To date, as-made SWCNT transistors are usually p-type in air, and it still remains challenging for realizing n-type devices. Herein, we present efficient and reversible electron doping of semiconductor-enriched single-walled carbon nanotubes (s-SWCNTs) by firstly utilizing decamethylcobaltocene (DMC) deposited by a simple spin-coating process at room temperature as an electron donor.

Synergistic Effects in CNTs-PdAu/Pt Trimetallic Nanoparticles with High Electrocatalytic Activity and Stability.

We present a straightforward physical approach for synthesizing multiwalled carbon nanotubes (CNTs)-PdAu/Pt trimetallic nanoparticles (NPs), which allows predesign and control of the metal compositional ratio by simply adjusting the sputtering targets and conditions. The small-sized CNTs-PdAu/Pt NPs (~3 nm, Pd/Au/Pt ratio of 3:1:2) act as nanocatalysts for the methanol oxidation reaction (MOR), showing excellent performance with electrocatalytic peak current of 4.4 A mg and high stability over 7000 s.

Self-Decoration of PtNi Alloy Nanoparticles on Multiwalled Carbon Nanotubes for Highly Efficient Methanol Electro-Oxidation.

Abstract: A simple one-pot method was developed to prepare PtNi alloy nanoparticles, which can be self-decorated on multiwalled carbon nanotubes in [BMIm][BF] ionic liquid. The nanohybrids are targeting stable nanocatalysts for fuel cell applications. The sizes of the supported PtNi nanoparticles are uniform and as small as 1-2 nm.

Encapsulated Silver Nanoparticles Can Be Directly Converted to Silver Nanoshell in the Gas Phase.

We report, for the first time, that an encapsulated silver nanoparticle can be directly converted to a silver nanoshell through a nanoscale localized oxidation and reduction process in the gas phase. Silver can be etched when exposed to a mixture of NH3/O2 gases through a mechanism analogous to the formation of aqueous Tollens' reagent, in which a soluble silver-ammonia complex was formed. Starting with Ag@resorcinol-formaldehyde (RF) resin core-shell nanoparticles, we demonstrate that RF-core@Ag-shell nanoparticles can be prepared successfully when the etching rate and RF thickness were well controlled.

Controlled synthesis and synergistic effects of graphene-supported PdAu bimetallic nanoparticles with tunable catalytic properties.

Graphene-supported bimetallic nanoparticles are promising nanocatalysts, which can show strong and tunable catalytic activity and selectivity. Herein room-temperature-ionic-liquid-assisted metal sputtering is utilized to synthesize PdAu bimetallic nanoparticles on graphene with bare surface, small size, high surface density and controlled Pd-to-Au ratio. This controllable synthetic approach is green-chemistry compatible and totally free of additives and byproducts.

Green-chemistry Compatible Approach to TiO-supported PdAu Bimetallic Nanoparticles for Solvent-free 1-Phenylethanol Oxidation under Mild Conditions.

TiO-supported PdAu bimetallic nanoparticles (NPs) with small size and good dispersity were prepared by the room-temperature ionic liquid-assisted bimetal sputtering, which is simple, environmentally friendly, and free of additives and byproducts. Pd/Au atomic ratio can be tuned by controlling the sputtering conditions simply. High catalytic activity was found in PdAu-NPs-TiO hybrids for solvent-free selective oxidation of 1-phenylethanol using O as the oxidant at the low temperature of 50 °C and low pressure of 1 atm.