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Introducing nanostructured metals with ultraviolet plasmonic characters has attracted much attention for fabricating high performance optoelectronic devices in the shorter wavelength spectrum. In this work, platinum nanoparticles (PtNPs) with controlled plasmonic responses in ultraviolet wavelengths were successfully synthesized. To demonstrate the promising availability, PtNPs with desired sizes were deposited on a hexagonal ZnO microwire via Ga-doping (PtNPs@ZnO:Ga MW). Under ultraviolet illumination, typical near-band-edge emission of ZnO:Ga MW was considerably enhanced; meanwhile, the photocurrent is much larger than that of the bare MW. Thereby, the enhanced phenomena of a ZnO:Ga MW is related to localized surface plasmon resonances of the decorated PtNPs. A single MW with a hexagonal cross-section can be a potential platform to construct a whispering gallery mode (WGM) cavity due to its total inner wall reflection. Given this, the influence of PtNPs via ultraviolet plasmons on lasing features of the ZnO:Ga MW was tested. The lasing characteristics are significantly enhanced, including lasing output enhancement, a clear reduction of the threshold and the improvement of the quality factor. To exploit the working principle, PtNPs serving as powerful ultraviolet plasmons can couple with ZnO:Ga excitons, accelerating radiative recombination. Since fabricating stable, typical nanostructured metals with ultraviolet plasmons remains a challenging issue, the results illustrated in the work may offer a low-cost and efficient scheme for achieving plasmon-enhanced wide-bandgap semiconductor based ultraviolet optoelectronic devices with excellent performances.

The collective oscillation of conduction electrons at the interface between metallic nanostructures and semiconductors has become one of the most attractive approaches to facilitate the luminous efficiency of light-emitting materials and devices. In this work, a single Ga-doped ZnO microwire covered by Ag nanowires (AgNWs@ZnO:Ga MW) was utilized to construct a promising ultraviolet light source, with p-GaN serving as a hole injection layer. In addition to substantially enhancing the light output, the electroluminescence (EL) features also illustrated that the dominating peak wavelength of the heterojunction diode was centered around 375.0 nm, accompanied by spectral linewidth narrowing to around 10 nm, suggesting that radiative recombination was primarily distributed in the single ZnO:Ga MW in the diode operation. The modulation of the emission features by the Ag nanowires, especially the typical near-band-edge (NBE) emission dominating the heterojunction diode, can be assigned to the near-perfect matching between the AgNWs-plasmons and the ZnO:Ga excitons, leading to the radiation recombination rate of the electron–hole in the ZnO:Ga MW channel being faster than the others. Therefore, the proposed strategy of incorporating ultraviolet plasmonic metallic nanostructures can be utilized to construct high-performance optoelectronic devices in the short wavelength spectral region.

In addition to the plasmon-mediated resonant coupling mechanism, plasmon-induced hot electron transfer can provide an alternative approach to construct high-performance optoelectronic devices for various applications, including photodetectors, photovoltaics, and molecular biology. In this work, a single Ga-doped ZnO microwire covered by large size (the diameter d ⋍ 200 nm) Ag nanoparticles (AgNP@ZnO:Ga MW) was prepared. Due to the excitation of hybrid quadrupole plasmons, ultraviolet whispering gallery mode lasing with a low threshold and significant enhancement of the optical output intensity was realized. Particularly, electron–hole plasma (EHP) lasing features, such as the redshift of the lasing band and the broadening of the spectral linewidth, could also be captured. This excellent phenomenon can be attributed to the hybrid quadrupole plasmon-induced generation and injection of hot electrons, resulting in bandgap renormalization due to the mismatch of the hybrid quadrupole plasmons and the ZnO:Ga excitons. The prompt hot electron generation and injection induced EHP-lasing characteristics can provide new possibilities for designing high-performance optoelectronic devices. More importantly, the proposed bandgap renormalization also enables the high-level engineering of the optoelectronic features by fine tuning the plasmonic behaviors.

MCo2O4 (M = Mn,Ni) microparticles were synthesised by a simple hydrothermal solvothermal method. The samples were characterised by X-ray diffraction, X-ray energy dispersive spectroscopy and scanni...

At present, museums are facing not only rare opportunities, but also many new challenges. In order to realize the scientific development of the museum, this paper proposes a design method of multi view virtual display system of Museum Cultural Relics based on AR-VR fusion technology. Through optimizing the hardware configuration structure of the system, improving the operation effect of the system, further optimizing the multi view virtual display algorithm, and optimizing the system software performance, the effective design of multi view virtual display system of Museum cultural relics is realized. Experiments show that the design of Museum Cultural Relics multi view virtual display system based on AR-VR fusion technology has high effectiveness in the practical application process, and fully meets the research requirements.

In emerging miniaturized applications, semiconductor micro/nanostructures laser devices have drawn great public attentions of late years. The device performances of micro/nanostructured microlasers are highly restricted to the different reflective conditions at various side surfaces of microresonators and junction interface quality. In this study, an electrically driven whispering-gallery-mode (WGM) microlaser composed of a Ga-doped ZnO microwire covered by a MgO layer (MgO@ZnO:Ga MW) and a p-type GaN substrate is illustrated experimentally. Incorporating a MgO layer on the side surfaces of ZnO:Ga MWs can be used to reduce light leakage along the sharp edges and the ZnO:Ga/GaN interface. This buffer layer incorporation also enables engineering the energy band alignment of n-ZnO:Ga/p-GaN heterojunction and manipulating the current transport properties. The as-constructed n-MgO@ZnO:Ga MW/p-GaN heterojunction device can emit at an ultraviolet wavelength of 375.5 nm and a linewidth of about 25.5 nm, achieving the excitonic-related recombination in the ZnO:Ga MW. The broadband spectrum collapsed into a series of sharp peaks upon continuous-wave (CW) operation of electrical pumping, especially for operating current above 15.2 mA. The dominant emission line was centered at 378.5 nm, and the line width narrowed to approximately 0.95 nm. These sharp peaks emerged from the spontaneous emission spectrum and had an average spacing of approximately 5.5 nm, following the WGM cavity modes. The results highlight the significance of interfacial engineering for optimizing the performance of low-dimensional heterostructured devices and shed light on developing future miniaturized microlasers.

Ultraviolet light-emitting materials and devices with high-efficiency are required for many applications. One promising way to enhance the ultraviolet luminescence efficiency is by incorporating plasmonic nanostructures. However, a large energy mismatch between the plasmons and the light emitters greatly limits the direct realization of light enhancement. In this work, a single Ga-doped ZnO microwire prepared with large-sized Ag nanoparticle (the diameter d ∼ 200 nm) deposition (AgNPs@ZnO:Ga MW) was utilized to construct a high-performance heterojunction diode, with p-GaN serving as the hole injection layer. In addition to enhanced optical output, the emission spectra also revealed that typical near-band-edge (NBE) emission with higher wavelength stability centered around 378.0 nm was achieved, accompanied by narrowing of the spectral linewidth to around 10 nm. Thus, the interfacial and p-GaN emissions were successfully suppressed. The spectral profile of the emission spectra of the heterojunction diodes precisely matched the photoluminescence spectrum of the single ZnO:Ga MW, which indicates that the single ZnO:Ga MW can act as the active region for the radiative recombination of electrons and holes in the diode operation. In the emission mechanism, hybrid quadrupole plasmons induce the generation of hot electrons, which are then injected into the conduction band of the neighboring ZnO:Ga and are responsible for the NBE-type emission of the single MW based heterojunction diode. This novel emission enhancement and modulation principle can aid in the design and development of new types of luminescent materials and devices with high-efficiency, spectral stability and spectral purity.

In this work, ultraviolet Fabry-Perot (FP) microlaser, made of an individual rectangular-shaped ZnO microwire, was achieved. The bilateral smooth facets and single-crystalline specificity of as-grown ZnO microwires can enable the realizing of lateral FP microresonators. By incorporating Ag nanowires (AgNWs), plasmon-enhanced FP lasing performances of an individual ZnO microwire, specifically for the sharply reduced threshold, increased lasing intensity and increased Q-factor, were achieved. Accordingly, the enhanced working principle was implemented, and is resorting to the confinement and enhancement of localized electromagnetic-field produced by AgNWs, which can make up the metal loss and accelerate more radiative recombination. Thereby, the incorporation of a rectangular-shaped microwire and AgNWs via desired ultraviolet plasmons can be used to exploit the modulation of metal nanostructures on lasing characteristics of wide bandgap semiconductors. Further, this study also suggestes that AgNWs with excellent ultraviolet plasmons can be generally utilized to modulate the optoelectronic characteristics of wide bandgap semiconductor materials and devices, indicating its underlying applications in fabricating high-performance light-emitting diodes and lasers, photodetectors and so on, working in the ultraviolet wavelengths.

Realizing dynamic regulation of specific optical components while being easy to integrate with photonic circuits will have a revolutionary impact on tunable laser sources, active filters, and all-optical switching/integration. Here, we demonstrate a temperature tunable Ga-doped ZnO microresonator with a conductivity of ∼1.75 S/cm controlled by the injection current and realize point-to-point heating. The shift in the resonant wavelength with a tuning range of 2 nm for TE66 mode is achieved by the effect of current-induced temperature rising on the refractive index of the microresonator crystal, namely, the thermo-optic effect. Meanwhile, the thermo-optic coefficient of 16.7 × 10−4/K around the bandgap energy of ZnO is also obtained. This operating mode of electronically controlled temperature establishes a solid foundation for the practicality and integration of tunable lasers.

Artificial muscles possess a vast potential in accelerating the development of robotics, exoskeletons, and prosthetics. Although a variety of emerging actuator technologies are reported, they suffer from several issues, such as high driving voltages, large hysteresis, and water intolerance. Here, a liquid metal artificial muscle (LMAM) is demonstrated, based on the electrochemically tunable interfacial tension of liquid metal to mimic the contraction and extension of muscles. The LMAM can work in different solutions with a wide range of pH (0-14), generating actuation strains of up to 87% at a maximum extension speed of 15 mm s-1 . More importantly, the LMAM only needs a very low driving voltage of 0.5 V. The actuating components of the LMAM are completely built from liquids, which avoids mechanical fatigue and provides actuator linkages without mechanical constraints to movement. The LMAM is used for developing several proof-of-concept applications, including controlled displays, cargo deliveries, and reconfigurable optical reflectors. The simplicity, versatility, and efficiency of the LMAM are further demonstrated by using it to actuate the caudal fin of an untethered bionic robotic fish. The presented LMAM has the potential to extend the performance space of soft actuators for applications from engineering fields to biomedical applications.

Owing to great luminescent monochromaticity, high stability, and independent of automatic color filter, low dimensional ultraviolet light-emitting diodes (LEDs) via the hyperpure narrow band have attracted considerable interest for fabricating miniatured display equipments, solid state lighting sources, and other ultraviolet photoelectrical devices. In this study, a near-ultraviolet LED composed of one Ga-doped ZnO microwire (ZnO:Ga MW) and p-GaN layer was fabricated. The diode can exhibit bright electroluminescence (EL) peaking at 400.0 nm, with a line width of approximately 35 nm. Interestingly, by introducing platinum nanoparticles (PtNPs), we achieved an ultraviolet plasmonic response; an improved EL, including significantly enhanced light output; an observed blueshift of main EL peaks of 377.0 nm; and a reduction of line width narrowing to 10 nm. Working as a powerful scalpel, the decoration of PtNPs can be employed to tailor the spectral line profiles of the ultraviolet EL performances. Also, a rational physical model was built up, which could help us study the carrier transportation, recombination of electrons and holes, and dynamic procedure of luminescence. This method offers a simple and feasible way, without complicated fabricating technology such as an added insulating layer or core shell structure, to realize hyperpure ultraviolet LED. Therefore, the proposed engineering of energy band alignment by introducing PtNPs can be employed to build up high performance, high spectral purity luminescent devices in the short wavelengths.

Three-dimensional (3D) micro/nano hierarchical structure semiconductor catalysts not only inherit the excellent properties of single nanometer-size building blocks resulting from their high specific surface area and high activity but also provide the merits of high dispersion and easy recovery of microstructures. Herein, the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres have been prepared via a one-step, environmentally friendly solvothermal method. Such interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres show an excellent photocatalytic activity, which is 121 times faster than that of the commercial Cu2O powders, and is one of the highest reported to date in the Ag/Cu2O composite materials for the degradation of Methyl Orange (MO) under visible light illumination. Our experimental results for photodegradation of MO also indicate that the existence of Cu in the products does not favor high photocatalytic activity for Ag/Cu2O composites, which may be due to the existence of excess metal in the products which provides the recombination centers for electron–hole pairs. After five consecutive cycles, the photocatalytic activity of the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres almost remains unchanged, indicating that they are photostable during the photodegradation of MO. Most importantly, such micrometer-sized overall structures of the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres enable them to be recycled and reused easily from solution by natural settlement in a short time. These results suggest that the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres had potential applications in visible light photocatalysis for environmental remediation.

Because of the superlattice structures comprising periodic and alternating crystalline layers, one-dimensional photon crystals can be employed to expand immense versatility and practicality of modulating the electronic and photonic propagation behaviors, as well as optical properties. In this work, individual superlattice microwires (MWs) comprising ZnO and Ga-doped ZnO (ZnO/ZnO:Ga) layers were successfully synthesized. Wavelength-tunable multipeak emissions can be realized from electrically driven single superlattice MW-based emission devices, with the dominant wavelengths tuned from ultraviolet to visible spectral regions. To illustrate the multipeak character, single superlattice MWs were selected to construct fluorescent emitters, and the emission wavelength could be tuned from 518 to 562 nm, which is dominated by Ga incorporation. Especially, by introducing Au quasiparticle film decoration, emission characteristics can further be modulated, such as the red shift of the emission wavelengths, and the multipeaks were strongly modified and split into more and narrower subbands. In particular, electrically pumped exciton-polariton emission was realized from heterojunction diodes composed of single ZnO/ZnO:Ga superlattice MWs and p-GaN layers in the blue-ultraviolet spectral regions. With the aid of localized surface plasmons from Au nanoparticles, which deposited on the superlattice MW, significant improvement of emission characteristics, such as enhancement of output efficiencies, blue shift of the dominant emission wavelengths, and narrowing of the spectral linewidth, can be achieved. The multipeak emission characteristics would be originated from the typical optical cavity modes, but not the Fabry-Perot mode optical cavity formed by the bilateral sides of the wire. The resonant modes are likely attributed to the coupled optical microcavities, which formed along the axial direction of the wire; thus, the emitted photons can be propagated and selected longitudinally. Therefore, the novel ZnO/ZnO:Ga superlattice MWs with a quadrilateral cross section can provide a potential platform to construct multicolor emitters and low-threshold exciton-polariton diodes and lasers.

The NiO/NiCo2O4 mixtures with unique yolk-shell structure were synthesized by a simple hydrothermal route and subsequent thermal treatment. The elemental distribution, composition, and microstructure of the samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscope (SEM), respectively. The microwave absorption property was investigated by using vector network analysis (VNA). The results indicated that the excellent electromagnetic wave absorption property of the NiO/NiCo2O4 mixtures was achieved due to the unique yolk-shell structure. In detail, the maximum reflection loss (RL) value of the sample reached up to − 37.0 dB at 12.2 GHz and the absorption bandwidth with RL below − 10 dB was 4.0 GHz with a 2.0-mm-thick absorber. In addition, the NiO/NiCo2O4 mixtures prepared at high temperature, exhibited excellent thermal stability. Possible mechanisms were investigated for improving the microwave absorption properties of the samples. Electronic supplementary material The online version of this article (10.1186/s11671-019-2988-9) contains supplementary material, which is available to authorized users.

Achieving high-brightness and high-efficiency low-dimensional light sources remains a challenging issue due to the lack of high electrical conductance electrodes, as well as the efficient charge injection into the luminescent layer. Herein, by employing chemical vapor deposition methods, individual ZnO microwires with heavily Ga-impurity (GZO MWs) have been successfully synthesized, and then directly assembled on p-GaN substrate to form a heterostructure light-emitting device. In the device, the single GZO MW, which possessing metallic behavior, can function as an outstanding conductance electrode, whilst an efficient luminescence layer. Electroluminescence (EL) characteristics of the single GZO MW-diode operated under forward bias were performed, yielding bright, blue/green lighting with the main peaks positioned at 450 nm and spectral line width of 90 nm. While it also can emit strong broadband, stable and monochromatic white emission under reverse bias. The dual-color-illuminating can be switched repeatedly by reversing the bias polarity. The bias-polarity-switched light source enables independent control over the EL illuminating-color and brightness. The fabrication of single MW based color-switchable light-emitting diode can afford a promising scheme toward the miniaturized, and smart light sources, which hold tremendous power in optical communication, optoelectronic devices and photoelectricity encoders.

Monodispersed and uniform hexagonal thin plate-like magnesium-aluminum layered double hydroxide intercalated with CO32− (MgAl–CO32−-LDH) is synthesized by an ethanol–water mediated solvothermal method. The maximum adsorption capacities of the as-synthesized and calcined MgAl − CO 3 2 − − LDH are 129.9 and 143.27 mg g−1, respectively, which are higher than those of the other metal oxide nanostructures reported to date. More importantly, although N2 adsorption–desorption analysis indicates that the BET surface area changed from 24.74 m2 g−1 for the as-synthesized MgAl − CO 3 2 − − LDH to 165.07 m2 g−1 for the calcined MgAl − CO 3 2 − − LDH , the as-synthesized and calcined hexagonal thin plate-like MgAl − CO 3 2 − − LDH structures show similar adsorption capacity of Congo red (CR) from aqueous solution. The adsorption mechanism for the as-prepared LDH is anion exchange while adsorption mechanism for the calcined LDH is reconstruction. Our study opens a new insight for understanding and preparing high-performance adsorbents for organic dye removal.

Over a long period of time, single iron oxide (Fe2O3) or cobalt oxide (Co2O3) has been extensively studied for magnetic absorbing materials. Recently, some nanoscale compounds composed of two ferrites have been reported for better electromagnetic absorbing properties because of collectively corporation. However, there are few reports about other magnetic absorbing materials. In addition, morphology control for better absorbing performance remains challenging. Here, the monodispersed, uniform rod-shaped FeCO3/CoCO3 microparticles are successfully synthesized by a facile one-step solvothermal method for the first time. The experimental results show that the reflection loss (RL) value of the paraffin composites with thickness of 2.0 mm is less than −10 dB in the frequency range of 6.72–15.92 GHz and the minimum RL value of −31.86 dB at 12.88 GHz is obtained, which demonstrates that the as-prepared FeCO3/CoCO3 microparticles have excellent magnetic and microwave absorbing properties.

Many nanomaterials have been reported for the removal of toxic inorganic metal ions. Some conventional micro- or nano-structured adsorbents are subject to serious aggregation. Here, well-dispersed, Fe(OH)3 colloid nanoparticles have been effectively deposited onto the surfaces of hierarchical γ-AlOOH nanostructures to form γ-AlOOH/Fe(OH)3 with hierarchical structures via an electrostatic attraction without forming large aggregates. The monodispersed γ-AlOOH/Fe(OH)3 with hierarchical structures have high specific surface areas and large pore volumes, which are used as adsorbents to remove anion species of As(V) and Cr(VI) from aqueous solution. The maximum capacities of the monodispersed γ-AlOOH/Fe(OH)3 with hierarchical structures for As(V) and Cr(VI) in this study are determined at 43.8 mg g−1 and 13.1 mg g−1, respectively, which are higher than those of the other metal oxide nanostructures reported to date. In addition, the adsorption rates of As(V) and Cr(VI) onto the monodispersed γ-AlOOH/Fe(OH)3 with hierarchical structures are rather fast. The γ-AlOOH/Fe(OH)3 hierarchical micro/nanoflower structures show high adsorption capacity for removing the anion species of As(V) and Cr(VI), demonstrating a promising potential in environmental remediation.

Tailored design of photocatalysts with complicated hollow structures is of great importance for promoting environmental remediation. Herein, a monodispersed CuO yolk-shelled structure is synthesized for the first time by simple calcination treatment of a pre-synthesized Cu–EG (ethylene glycol) complex with yolk-shelled structure using a simple, environmentally friendly and glycerol-mediated solvothermal method. Ostwald ripening is the main formation mechanism for the yolk-shelled structure. Such CuO yolk-shelled structures show excellent photocatalytic activity, which is 3.65 times faster than that of the commercial CuO powders and is one of the highest reported photocatalytic activities to date in the CuO nanomaterials for the degradation of rhodamine B (RhB) under visible light irradiation. Such a preferable photocatalytic activity is mainly attributed to the unique yolk-shelled structure, which can enable higher multiple light reflections and scattering between the outer spherical shell and the interior core compared with commercial CuO powders, to provide a more efficient way to enhance light-harvesting efficiency.

Some conventional micro- or nano-structured adsorbents are subject to the problem that they can hardly show most of their adsorption sites for adsorbing pollutants in solution because of serious aggregation of adsorbents. Here, monodispersed hollow aluminosilica microsphere (HAM)@hierarchical γ-AlOOH nanomaterials have been first synthesized via a simple one-step template method. Positively charged Fe(OH)3 colloid nanoparticles with a diameter of about 4 nm have been effectively deposited onto the negatively charged surfaces of the hierarchical γ-AlOOH nanosheets to form HAM@γ-AlOOH/Fe(OH)3 with hierarchical structure via electrostatic attraction without forming large aggregates. Both the HAM@γ-AlOOH and HAM@γ-AlOOH/Fe(OH)3 with hierarchical structure have high specific surface areas and large pore volumes. The HAM@γ-AlOOH with the electronegative surface and the HAM@γ-AlOOH/Fe(OH)3 with the electropositive surface are used as adsorbents to remove methylene blue (MB) (cationic dye) and congo red (CR) (anionic dye) from aqueous solution, respectively. The maximum capacities of the monodispersed HAM@γ-AlOOH and HAM@γ-AlOOH/Fe(OH)3 with hierarchical structure for MB and CR are determined to be 87.80 mg g−1 and 252.53 mg g−1, respectively, which are higher than those of other metal oxide nanostructures reported to date. In addition, the adsorption rates of MB and CR onto the monodispersed HAM@γ-AlOOH and HAM@γ-AlOOH/Fe(OH)3 with hierarchical structure are rather fast. This study also shows that efficient adsorbents for organic pollutant removal can be designed by depositing nanoparticles with high adsorption capacity on mesoporous supports with abundant surface hydroxyl groups and a large surface area.

Due to their outstanding surface-to-volume ratio, highly smooth surface, and well-defined crystal boundary, semiconducting micro-/nanocrystals have been used as a pivotal platform to fabricate multifunctional optoelectronic devices, such as superresolution imaging devices, solar concentrators, photodetectors, light-emitting diodes (LEDs), and lasers. In particular, micro-/nanocrystals as key elements can be employed to tailor the fundamental optical and electronic transport properties of integrated hetero-/homostructures. Herein, ZnO microcrystal-decorated pre-synthesized Ga-doped ZnO microwire (ZnO@ZnO:Ga MW) was prepared. The single ZnO@ZnO:Ga MW can be used to construct optically pumped Fabry–Perot (F–P) mode microlasers, with the dominating lasing peaks centered in the violet spectral region. Stabilized exciton-polariton emissions from single ZnO@ZnO:Ga MW-based heterojunction diode can also be realized. The deposited ZnO microcrystals can facilitate the strong coupling of F–P optical modes with excitons, leading to the formation of exciton-polariton features in the ZnO@ZnO:Ga MW. Therefore, the waveguiding lighting behavior and energy-band alignment of ZnO microcrystal-sheathed ZnO:Ga MW radial structures should be extremely attractive for potential applications in semiconducting microstructure-based optoelectronic devices, such as micro-LEDs, laser microcavities, waveguides, and photodetectors.

Monodispersed LaCO3OH microgears with a novel plum blossom-like structure are prepared by a simple, reliable, environmentally-friendly and glycerol-mediated solvothermal method for the first time. By studying the effect of the experimental parameters on the morphology of LaCO3OH structures, we find that urea and glycerol at high concentration play a significant role in the formation of the plum blossom-like LaCO3OH microgears. In addition, we observe that the morphology evolution of the LaCO3OH microgears is from wires, spheres composed of rods, to plum blossom-like products with the increase of reaction time. More importantly, PL results demonstrate that the LaCO3OH microgears show a stronger PL than that of other structures, such as wires and spheres.