A facile solvothermal route to synthesize S,N co‐doped graphene quantum dots (S,N‐GQDs) with unique optical properties is demonstrated. Three absorption bands are observed at 338, 467, and 557 nm, which different from any previous reports. The photoluminescent spectra display emissions in three primary colors that independent of the excitation wavelength, within wavelength ranges 340–420 460–540 560–620 nm. PL indicate each emission related a single band. It proposed luminescent centers...

A one-step microwave synthesis of N-doped hydroxyl-functionalized carbon dots (CDs) with ultra-high fluorescence quantum yields (QYs) 99% is reported. These QY CDs were synthesized using citric acid and amino compound-containing hydroxyls like ethanolamine tris(hydroxylmethyl)aminomethane. Amino carboxyl moieties can form amides through dehydration condensation reactions, these act as bridges between hydroxyl groups, modify groups on the surface CDs. The entire reaction be carried out within...

For practical applications of carbon dots (CDs), a major challenge is to prevent the notorious aggregation-caused quenching (ACQ) effect. Herein, new type CDs (CD1) has been developed that can transform from ACQ an enhancement fluorescence by aggregation-induced emission (AIE). The blue suppressed ACQ. However, this accompanied phenomenon AIE at longer wavelength, resulting in emergence and gradual yellow fluorescence. obtained CD1 solid powder shows bright with photoluminescence quantum...

Time‐dependent afterglow colored (TDAC) behavior differs from static by involving wavelength changes, enabling low‐cost, high‐level encryption and anti‐counterfeiting. However, the existing carbon dot (CD)‐based TDAC materials lack a clear mechanistic explanation controllable significantly hindering progress of practical applications in this field. In study, we synthesized CDs composites with customizable tunable wavelengths across visible region. Furthermore, elucidated underlying mechanism...

Methylammonium (MA) lead halide (MAPbX3, X = Cl, Br, I) perovskite quantum dots (PQDs) are very sensitive to environment (moisture, oxygen, and temperature), suffering from poor stability. To improve the stability, we synthesized silica-coated PQDs (SPQDs) by an improved ligand-assisted reprecipitation method through simply mixing stirring under room temperature in air without adding water catalyst, whole process took only a few seconds. The photoluminescence (PL) spectra of SPQDs can be...

Miniaturized solid-state lasers with a single longitudinal mode are vital for various photonic applications. Here we prepare red-emissive carbon dots (CDs) photoluminescence quantum yield (PLQY) of 65.5 % by combining graphitic nitrogen doping and surface modification. High-concentration alters the CDs' emission from blue to red, while electron-donating groups polymer coating on their surfaces improve PLQY photostability. The CDs exhibit excellent stimulated characteristics, low threshold...

Carbon dots (CDs) that exhibit emission over the whole visible spectrum are desired for use in light-emitting diodes (LEDs). Here, CDs displaying tunable fluorescence region synthesized. Different concentrations of uniformly dispersed epoxy resin and coated on 405 nm LED chips to obtain monochrome blue, cyan, green, yellow, red, deep red LEDs yield a color gamut covering 99.4% National Television Standards Committee (NTSC) standard. These display similar high stability. Furthermore, warm...

Time‐dependent afterglow colored (TDAC) behavior differs from static by involving wavelength changes, enabling low‐cost, high‐level encryption and anti‐counterfeiting. However, the existing carbon dot (CD)‐based TDAC materials lack a clear mechanistic explanation controllable significantly hindering progress of practical applications in this field. In study, we synthesized CDs composites with customizable tunable wavelengths across visible region. Furthermore, elucidated underlying mechanism...

Two classes of laterally azo-bridged H-shaped ferroelectric liquid crystals (FLCs), incorporating azobenzene and disperse red 1 (DR-1) chromophores along the FLC polar axes, were synthesized characterized by polarized light microscopy, differential scanning calorimetry, 2D X-ray diffraction analysis, electro-optical investigations. They represent first materials exhibiting ground-state, thermodynamically stable enantiotropic SmC* phase, i.e., ground-state ferroelectricity. Second harmonic...

Cloaking is a challenging topic in the field of wave motion, and significant theoretical value. In this article, type carpet cloak has been theoretically designed for water waves by using effective medium transformation theory. This device, created three-dimensional printer, composed periodic structure which realizes equivalent anisotropic depth. We demonstrate its excellent cloaking performance numerically experimentally wide range frequencies angles incidence, with low attenuation...

Abstract Miniaturized solid‐state lasers with a single longitudinal mode are vital for various photonic applications. Here we prepare red‐emissive carbon dots (CDs) photoluminescence quantum yield (PLQY) of 65.5 % by combining graphitic nitrogen doping and surface modification. High‐concentration alters the CDs’ emission from blue to red, while electron‐donating groups polymer coating on their surfaces improve PLQY photostability. The CDs exhibit excellent stimulated characteristics, low...

In the framework of theory non‐local elasticity, a model on buckling weakened nanobeam subjected to constant axial load is presented. Based this model, characteristic equation for simply supported obtained, through which value can be determined. The influences small length scale and junction are discussed. It shown that dependent upon coefficient, stiffness location.

We report the coexistence of TE and TM surface modes in certain same frequency domain at interface between one isotropic regular medium another biaxially anistotropic left-handed medium. The conditions for existence polarized waves anisotropic materials are identified, respectively. Poynting vector energy density associated with calculated. Depending on system parameters, either or can have time averaged directed to opposite mode phase velocity. It is seen that characteristics media...

Abstract Optical efficiency is of paramount importance to emerging ultra‐miniature projector products. We have developed experimental bistable ferroelectric‐liquid‐crystal‐on‐Silicon (FLCOS) projection microdisplay devices using newly FLC materials aligned on obliquely‐deposited SiO 2 . These enable doubling illumination duty cycle, and hence achievable light output, while maintaining DC‐balanced electrical drive.

In this paper, the Goos-H?nchen shift on interface of uniaxially anisotropic left-handed materials is investigated exhaustively, and analytical expressions presented for cases optical axis being perpendicular parallel to interface, respectively. Moreover, conditions existence sign are determined. Under Fresnel approximation, expression around critical angle obtained, result shows that a function beam waist incident angle. A simple approximate lateral with equals also presented. Thus, general...

This work studies the wave propagation in embedded single‐walled carbon nanotubes (CNTs) conveying fluid and placed multi‐physical fields based on non‐local higher‐order strain gradient model with surface effect considered. The are modelled as Timoshenko beams. Utilising Hamilton's principle, governing equations of motion CNTs derived. solution for phase velocity is obtained, which can not only consider stiffness softening but also reflect enhancement scale parameter observed by experiments....

In this study, 3 at.% Yb3+: CaxSr1−xF2 nanopowders were synthesized via the chemical co-precipitation method. Highly transparent ceramics with various CaF2 concentrations fabricated by hot-pressed sintering. The exhibited a spherical shape slight agglomeration, and their particle size ranged from 26 nm to 36 nm. With an increase of concentration, peak changed significantly width emission band increased inhomogeneously. minimal fluorescence lifetime at wavelength 1011 was higher than 3.25 ms,...

The short shelf life of litchi is due to its rapid metabolism after being harvested. Refrigeration not a suitable method for preserving litchi, as the browning process that has been cryogenic will accelerate when it brought room temperature. This study introduces an alginate-based coating solution control post-harvest litchi. achieves this by simultaneously establishing crosslink and percolation networks, both which act barriers. network created using rod-like cellulose nanocrystals, possess...