Ultra-broadband microwave absorber and high-performance pressure sensor based on aramid nanofiber,polypyrrole and nickel porous aerogel

Electronic devices have become ubiquitous in our daily lives,leading to a surge in the use of microwave absorbers and wearable sensor devices across various sectors.A prime example of this trend is the aramid nanofibers/polypyrrole/nickel(APN)aerogels,which serve dual roles as both microwave absorbers and pressure sensors.In this work,we focused on the preparation of aramid nanofibers/polypyrrole(AP15)aerogels,where the mass ratio of aramid nanofibers to pyrrole was 1:5.We employed the oxidative polymerization method for the preparation process.Following this,nickel was thermally evaporated onto the surface of the AP15 aerogels,resulting in the creation of an ultralight(9.35 mg·cm^(-3)).This aerogel exhibited a porous structure.The introduction of nickel into the aerogel aimed to enhance magnetic loss and adjust impedance matching,thereby improving electromagnetic wave absorption performance.The minimum reflection loss value achieved was-48.7 dB,and the maximum effective absorption bandwidth spanned 8.42 GHz with a thickness of 2.9 mm.These impressive metrics can be attributed to the three-dimensional network porous structure of the aerogel and perfect impedance matching.Moreover,the use of aramid nanofibers and a three-dimensional hole structure endowed the APN aerogels with good insulation,flame-retardant properties,and compression resilience.Even under a compression strain of 50%,the aerogel maintained its resilience over 500 cycles.The incorporation of polypyrrole and nickel particles further enhanced the conductivity of the aerogel.Consequently,the final APN aerogel sensor demonstrated high sensitivity(10.78 kPa-1)and thermal stability.In conclusion,the APN aerogels hold significant promise as ultra-broadband microwave absorbers and pressure sensors.

Composites of In/C hexagonal nanorods and graphene nanosheets for high-performance electromagnetic wave absorption

In recent years,electromagnetic wave(EMW)absorption has been extensively investigated for solving EMW radiation and pollution.The metal-organic frameworks(MOFs)have attracted attention due to their low density and unique structure,which can meet the requirements of strong reflection loss(RL)and wide absorption bandwidth of EMW absorption materials.In this manuscript,indium nanoparticles/porous carbon(In/C)nanorods composites were prepared via the pyrolysis of nanorods-like In-MOFs at a low temperature of450°C.Indium nanoparticles are evenly attached and embedded on porous carbon.Low electrical conductivity of In/C nanorods is unfavorable to EMW absorption performance,which is due to the low temperature carbonization.Thus,graphene(Gr)nanosheets with high electrical conductivity are introduced to adjust electromagnetic parameters of In/C nanorods for enhancing EMW absorption.The minimum RL of the In/C-Gr-4 composite is up to-43.7 dB with a thin thickness of 1.30 mm.In addition,when the thickness is further reduced to 1.14 mm,the minimum RL of-39.3 dB at 16.1 GHz and effective absorption bandwidth of 3.7 GHz(from 14.3 to 18.0 GHz)can be achieved.This work indicates that In/C-Gr composites show excellent EMW absorption performance.

Photoemission oscillation in epitaxially grown van derWaalsβ-In_(2)Se_(3)/WS_(2) heterobilayer bubbles

Thin films of millimeter-scale continuous monolayer WS_(2) have been grown on SiO_(2)/Si substrate,followed by the deposition ofβ-In_(2)Se_(3) crystals on monolayer WS2 to prepare In_(2)Se_(3)/WS_(2) van deWaals heterostructures by a two-step chemical vapor deposition(CVD)method.After the growth of In_(2)Se_(3) at elevated temperatures,high densities of In_(2)Se_(3)/WS_(2) heterostructure bubbles with monolayer to multilayerβ-In_(2)Se_(3) crystals atop are observed.Fluorescence of the resultantβ-In_(2)Se_(3)/WS_(2) heterostructure is greatly enhanced in intensity upon the formation of bubbles,which are evidenced by the Newton’s rings in optical image owing to constructive and destructive interference.In photoluminescence(PL)mapping images of monolayerβ-In_(2)Se_(3)/monolayer WS2 heterobilayer bubble,significant oscillatory behavior of emission intensity is demonstrated due to constructive and destructive interference.However,oscillatory behaviors of peak position are also observed and come from a local heating effect induced by an excitation laser beam.The oscillatory mechanism of PL is further verified by changing the exterior pressure of bubbles placed in a home-made vacuum chamber.In addition,redshifted in peak position and broadening in peak width are observed due to strain effect during decreasing the exterior pressure of bubbles.

Microwave Synthesized In2S3@CNTs with Excellent Properties in Lithium-Ion Battery and Electromagnetic Wave Absorption

The three-dimensional nanoflower-like β-In2S3 composited with carbon nanotubes {CNTs） has been synthesized by a single mode micro- wave-assisted hydrothermal technique. The In2S3 and CNTs nanocomposites （In2S3@CNTs） were investigated as the anode materials of lithium batteries （LIBs） and the electromagnetic wave absorption materials. For LIBs applications, the In2S3@CNTs nanocomposite exhibited excellent cycling stability with a high reversible charge capacity of 575 mA·h·g-1 after 300 cycles at 0.S A·g^-1, In addition, the In2S3@CNTs used as electromagnetic wave absorber displayed a maximum reflection loss of-42.75 dB at 11.96 GHz with a thickness of 1.55 ram.

Broadband photodetector of high quality SbS nanowire grown by chemical vapor deposition

Low dimensional semiconductors can be used for various electronic and optoelectronic devices because of their unique structure and property.In this work,one-dimensional Sb2 S3 nanowires(NWs)with high crystallinity were grown via chemical vapor deposition(CVD)technique on SiO2/Si substrates.The Sb2 S3 NWs exhibited needle-like structures with inclined cross-sections.The lengths of Sb2S3 nanowires changed from 7 to 13μm.The photodetection properties of Sb2 S3 nanowires were comprehensively and systematically characterized.The Sb2S3 photodetectors show a broadband photoresponse ranging from ultraviolet(360 nm)to near-infrared(785 nm).An excellent specific detectivity of 2.1×10^(14)Jones,high external quantum efficiency of 1.5×10^(4)%,sensitivity of 2.2×10^(4)cm^(2)W^(-1)and short response time of less than 100 ms was achieved for the Sb2 S3 NW photodetectors.Moreover,the Sb2S3 NWs showed outstanding switch cycling stability that was beneficial to the practical applications.The high-quality Sb2S3 nanowires fabricated by CVD have great application potential in semiconductor and optoelectronic fields.

Broadband light absorption and photoresponse enhancement in monolayer WSe_(2) crystal coupled to Sb_(2)O_(3) microresonators

Monolayer(1L)transition metal dichalcogenides(TMDCs)have been attracting tremendous interest in recent years as promising candidate materials in atomic-scale optoelectronic devices due to their direct band gaps(1.5-2.2 eV)and strong light-matter interactions.Unfortunately,their practical applications are limited by low visible light absorption stemming from atomic thickness and negligible infrared response.Here,we report the triangular Sb_(2)O_(3) microresonators in wide thickness and lateral size distributions grown on 1L TMDCs and their created significant broadband enhancement of light adsorption and photoresponse in 1L WSe_(2) crystal via coexisting Fabry-Perot and whispering gallery type resonances.As an example of demonstration,1L WSe_(2) crystal coupled to Sb_(2)O_(3) microresonators with widely distributed sizes exhibits the enhanced visible light absorption by up to 5 folds and the simultaneously extended near infrared(NIR)one of more than 50%.For application of 1L WSe_(2) in photodetection,incorporation of Sb2O3 microresonators leads to significantly enhanced visible light responsivity by~10^(4) order and expanded NIR one of more than 400 mA·W^(-1).Similar results have been observed in the other 1L W(Mo)dichalcogenides coupled to Sb2O3 microresonators.This work provides a new route for development of the high-performance monolayer TMDCs-based optoelectronic devices.