Self-Assembly 3D Porous Crumpled MXene Spheres as Efficient Gas and Pressure Sensing Material for Transient All-MXene Sensors

Environmentally friendly degradable sensors with both hazardous gases and pressure efficient sensing capabilities are highly desired for various promising applications,including environmental pollution monitoring/prevention,wisdom medical,wearable smart devices,and artificial intelligence.However,the transient gas and pressure sensors based on only identical sensing material that concurrently meets the above detection needs have not been reported.Here,we present transient all-MXene NO_(2) and pressure sensors employing three-dimensional porous crumpled MXene spheres prepared by ultrasonic spray pyrolysis technology as the sensing layer,accompanied with water-soluble polyvinyl alcohol substrates embedded with patterned MXene electrodes.The gas sensor achieves a ppb-level of highly selective NO_(2) sensing,with a response of up to 12.11%at 5 ppm NO_(2) and a detection range of 50 ppb-5 ppm,while the pressure sensor has an extremely wide linear pressure detection range of 0.14-22.22 kPa and fast response time of 34 ms.In parallel,all-MXene NO_(2) and pressure sensors can be rapidly degraded in medical H_(2)O_(2) within 6 h.This work provides a new avenue toward environmental monitoring,human physiological signal monitoring,and recyclable transient electronics.

Interface Reversible Electric Field Regulated by Amphoteric Charged Protein-Based Coating Toward High-Rate and Robust Zn Anode

Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead to high anodic polarization.Here,we present a bio-inspired silk fibroin(SF)coating with amphoteric charges to construct an interface reversible electric field,which manipulates the transfer kinetics of Zn^(2+) and reduces anodic polarization.The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn^(2+) flux via the inter-play between the charged coating and adsorbed ions,endowing the Zn-SF anode with low polarization voltage and stable plating/stripping.Experimental analyses with theo-retical calculations suggest that SF can facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+) and provide nucleation sites for uniform deposition.Consequently,the Zn-SF anode delivers a high-rate performance with low voltage polarization(83 mV at 20 mA cm^(−2)) and excellent stability(1500 h at 1 mA cm^(−2);500 h at 10 mA cm^(−2)),realizing exceptional cumulative capacity of 2.5 Ah cm^(−2).The full cell coupled with Zn_(x)V_(2)O_(5)·nH_(2)O(ZnVO)cathode achieves specific energy of~270.5/150.6 Wh kg^(−1)(at 0.5/10 A g^(−1))with-99.8% Coulombic efficiency and retains~80.3%(at 5.0 A g^(−1))after 3000 cycles.

A highly efficient open-shell singlet luminescent diradical with strong magnetoluminescence properties

Developing open-shell singlet(OS)diradicals with high luminescent properties and exceptional single-molecule magnetoluminescence(ML)performance is extremely challenging.Herein,we propose a concept to enhance luminescent efficiency by adjusting the donor conjugation of OS diradicals,thereby achieving a highly luminescent diradical,DR1,with outstanding stability and making it a viable option for use in the emitting layer of organic light-emitting diodes(OLEDs).More importantly,the 0.5wt%-DR1 doped film demonstrates significant single-molecule magnetoluminescence(ML)properties.A giant ML value of 210%is achieved at a magnetic field of 7T,showing the great potential of DR1 in magneto-optoelectronic devices.

Excitation orthogonalized upconversion nanoprobe for instant visual detection of trinitrotoluene

Excitation-emission orthogonalized luminescent upconversion nanoparticles(OUCNPs),which can respond to changes in external stimuli accordingly,show great promise in many intelligent applications.However,the construction of such materials mostly relies on the selective absorption of Nd3+and Yb3+at different wavelengths and the long-range energy migration between the layers,resulting in complex structures and limited orthogonal luminescence intensity.Herein,we developed a relatively simple structure of OUCNPs(β-NaErF4@NaLuF4@NaYF4:20%Yb,2%Er@NaLuF4),where the fluorescence emission switches from red to green when the excitation wavelength is shifted from 808 to 980 nm.This structure exhibits high-quality,independent,and non-interfering orthogonal luminescence properties without Nd3+sensitization and long-range energy migration.As a proof of concept,we demonstrate the application of the designed OUCNPs in anti-counterfeiting.We also prepared OUCNPs@PEI(PEI=polyethylenimine)self-referencing fluorescent probes to enable quantitative analysis of trinitrotoluene(TNT)in solution with a detection limit of 3.04μM.The probes can be made into test strips for portable on-site visual detection of TNT,and can also be used to image latent fingerprints and detect explosive residues in fingerprints simultaneously.The concept proposed in this work can be extended to the visual detection of a larger range of organic and biological molecules,and is highly promising for practical applications.

Microwave-assisted hydrothermal synthesis of Pt/SnO2 gas sensor for CO detection

In this paper,the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route.The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated.The results from the TEM test reveal that Pt grows on the SnO2 nanostructure,which was not found for bulk in this situ method,constructing Pt/SnO2.The results indicated that the sensor using 3.0 wt%Pt/SnO2 to 100 ppm carbon monoxide performed a superior sensing properties compared to 1.5 wt%and 4.5 wt%Pt/SnO2 at 225℃.The response time of 3.0 wt%sensor is 16 s to 100 ppm CO at225℃.Such enhanced gas sensing performances could be attributed to the chemical and electrical factors.In view of chemical factors,the presence of Pt facilitates the surface reaction,which will improve the gas sensing properties.With respect to the electrical factors,the Pt/SnO2 plays roles in increasing the sensor’s response due to its characteristic configuration.In addition,the one-step in situ microwave assisted process provides a promising and versatile choice for the preparation of gas sensing materials.

Construction of self-sensitized LiErF4:0.5%Tm^3+@LiYF4 upconversion nanoprobe for trace water sensing

LiErF4 was commonly used as a dipolar-coupled antiferromagnet,and was rarely considered as a luminescent material.Herein,we achieved the strong red upconversion emission of LiErF4 simply by an inert shell coating,i.e.,LiErF4@LiYF4.Owing to the unique and intrinsic ladder-like energy levels of Er3+ions,this LiErF4 core–shell nanostructures present red emission(~650 nm)under multi-band excitation in the near-infrared(NIR)region(~808,~980,and^1,530 nm).A brighter and monochromic red emission can be further obtained via doping 0.5%Tm3+into the LiErF4 core,i.e.,LiErF4:0.5%Tm3+@LiYF4.The enriched Er3+ions and strong monochromic red emission natures make LiErF4:0.5%Tm3+@LiYF4 nanocrystals very sensitive for trace water probing in organic solvents with detection limit of 30 ppm in acetonitrile,50 ppm in dimethyl sulfoxide(DMSO),and 58 ppm in N,N-dimethylformamide(DMF)under excitation of 808 nm.Due to their superior chemical and physical stability,these nanoprobes exhibit excellent antijamming ability and recyclability,offering them suitable for real-time and long-term water monitoring.