A clean transfer approach to prepare centimetre-scale black phosphorus crystalline multilayers on silicon substrates for field-effect transistors.

Recently reported direct growth of highly crystalline centimetre-sized black phosphorus (BP) thin films on mica substrates by pulsed laser deposition (PLD) has attracted considerable research interest. However, an effective and general transfer method to incorporate them into (opto-)electronic devices is still missing. Here, we show a wet transfer method utilizing ethylene-vinyl acetate (EVA) and an ethylene glycol (EG) solution to transfer high-crystalline large-area PLD-BP films onto SiO/Si substrates.

Direct observation of intrinsic room-temperature ferroelectricity in 2D layered CuCrPS.

Multiferroic materials have ignited enormous interest owing to their co-existence of ferroelectricity and ferromagnetism, which hold substantial promise for advanced device applications. However, the size effect, dangling bonds, and interface effect in traditional multiferroics severely hinder their potential in nanoscale device applications. Recent theoretical and experimental studies have evidenced the possibility of realizing two-dimensional (2D) multiferroicity in van der Waals (vdW) layered CuCrPS.

Achieving reinforcement learning in a three-active-terminal neuromorphic device based on a 2D vdW ferroelectric material.

Currently, for most three-terminal neuromorphic devices, only the gate terminal is active. The inadequate modes and freedom of modulation in such devices greatly hinder the implementation of complex neural behaviors and brain-like thinking strategies in hardware systems. Taking advantage of the unique feature of co-existing in-plane (IP) and out-of-plane (OOP) ferroelectricity in two-dimensional (2D) ferroelectric α-InSe, we construct a three-active-terminal neuromorphic device where any terminal can modulate the conductance state.

Rapid and ultrasensitive detection of SARS-CoV-2 spike protein based on upconversion luminescence biosensor for COVID-19 point-of-care diagnostics.

Here, we firstly introduce a detection system consisting of upconversion nanoparticles (UCNPs) and Au nanorods (AuNRs) for an ultrasensitive, rapid, quantitative and on-site detection of SARS-CoV-2 spike (S) protein based on Förster resonance energy transfer (FRET) effect. Briefly, the UCNPs capture the S protein of lysed SARS-CoV-2 in the swabs and subsequently they are bound with the anti-S antibodies modified AuNRs, resulting in significant nonradiative transitions from UCNPs (donors) to AuNRs (acceptors) at 480 nm and 800 nm, respectively. Notably, the specific recognition and quantitation of S protein can be realized in minutes at 800 nm because of the low autofluorescence and high Yb-Tm energy transfer in upconversion process.

One-Step, DNA-Programmed, and Flash Synthesis of Anisotropic Noble Metal Nanostructures on MXene.

Precise morphological control over anisotropic noble metal nanoparticles (ANPs) is one of the key issues in the nano-research field owing to their unique optoelectronic, magnetic, mechanical, and catalytic properties. Although nanostructures fabricated by the directed assembly of adsorbate have been widely demonstrated recently, facile yet universal synthesis of nanocrystal with tunable morphologies, green templates, no seeds, and high yield remains challenging. Herein, we develop a versatile method, allowing for the rapid, one-step, seedless, surfactant-free synthesis of a noble metal nanostructure with tunable anisotropy on MXene in a sequence-dependent manner through a single-DNA molecular regulator.

Facile Atomic-Level Tuning of Reactive Metal-Support Interactions in the Pt QDs@ HF-Free MXene Heterostructure for Accelerating pH-Universal Hydrogen Evolution Reaction.

Supported metallic nanoparticles render highly tunable physical and chemical properties to mixed-dimensionality materials in electrocatalysts. However, some supports are susceptible to being dissolved in acidic solution or are unstable in ambient air. The development of high-performance catalysts has been facing the major hurdles of the sluggish activity in alkaline solution and requesting high energy to stabilize the nanoparticles on their supports, challenging the pH-universality and the applicability of the supported metallic nanoparticles.

Effective Piezo-Phototronic Enhancement of Flexible Photodetectors Based on 2D Hybrid Perovskite Ferroelectric Single-Crystalline Thin-Films.

2D hybrid perovskites are very attractive for optoelectronic applications because of their numerous exceptional properties. The emerging 2D perovskite ferroelectrics, in which are the coupling of spontaneous polarization and piezoelectric effects, as well as photoexcitation and semiconductor behaviors, have great appeal in the field of piezo-phototronics that enable to effectively improve the performance of optoelectronic devices via modulating the electro-optical processes. However, current studies on 2D perovskite ferroelectrics focus on bulk ceramics that cannot endure irregular mechanical deformation and limit their application in flexible optoelectronics and piezo-phototronics.

Fluoride-Free 2D Niobium Carbide MXenes as Stable and Biocompatible Nanoplatforms for Electrochemical Biosensors with Ultrahigh Sensitivity.

Recently, 2D niobium carbide MXene has drawn vast attention due to its merits of large surface area, good metallic conductivity, and tunable band gap, making it desirable for various applications. However, the usage of highly toxic fluoride-containing etchant and quite long etching time in the conventional synthesis route has greatly hindered further exploration of MXene, especially restricting its biomedical application. Herein, novel fluoride-free NbCT nanosheets are prepared by a facile strategy of electrochemical etching (E-etching) exfoliation.

Efficient Energy Conversion and Storage Based on Robust Fluoride-Free Self-Assembled 1D Niobium Carbide in 3D Nanowire Network.

Owing to their high robustness and conductivity, 2D transition metal carbides and nitrides known as MXenes are considered as a promising material class for electrochemical catalysis, energy conversion, and storage applications. Nevertheless, conventional hazardous fluoride-based synthesis routes and the intense intralayer bonding restrict the development of MXenes. Herein, a fluoride-free, facile, and rapid method for synthesizing self-assembled 1D architecture from an MXene-based compound is reported.

A General Wet Transferring Approach for Diffusion-Facilitated Space-Confined Grown Perovskite Single-Crystalline Optoelectronic Thin Films.

Hybrid perovskite single-crystalline thin films are promising for making high-performance perovskite optoelectronic devices due to their superior physical properties. However, it is still challenging to incorporate them into multilayer devices because of their on-substrate growth. Here, a wet transfer method is used in transferring perovskite single-crystalline films perfectly onto various target substrates.

Universal Strategy for HF-Free Facile and Rapid Synthesis of Two-dimensional MXenes as Multifunctional Energy Materials.

Two-dimensional MXenes are promising for various energy-related applications such as energy storage devices and electrocatalysis of water-splitting. MXenes prepared from hydrofluoric (HF) acid etching have been widely reported. Nonetheless, the acute toxicity of HF acid impedes the large-scale fabrication of MXenes and their wide utilization in energy-related applications.

Electrochemically assisted flexible lanthanide upconversion luminescence sensing of heavy metal contamination with high sensitivity and selectivity.

Heavy metal contamination in water can pose lethal threats to public health; therefore it is highly desired to develop a rapid and sensitive sensor for monitoring water quality. Owing to their superior optical features, upconversion nanoparticles (UCNPs) are widely explored to detect metal ions based on resonance energy transfer to dye quenchers. However, these schemes heavily rely on the optical properties of the molecules, which limits the flexibility of the probe design.