We prepared novel photoanodes structured as FTO/ZnO nanoflowers/ZnTiO3/CdS/CdTeS/ZnS quantum dots (QDs) with highly exposed large specific area and energy coupling. The design of the photoanode expressed significant enhanced photoelectrochemical (PEC) performance such as improved absorption efficiency, reduced recombination rate, and enhanced charge transportation state, resulting in a significant increase in photoelectron current. The multinanoheterostructures photoanode provides a high photocatalytic activity and a maximum photocurrent density up to 9.41 mA/cm2 under AM 1.5 G illumination. The novel cosensitized multinanoheterostructures photoanodes lead to a remarkable and promising application in photoelectrochemical and water splitting reactions.

We prepared novel photoanodes structured as FTO/ZnO nanoflowers/ZnTiO3/CdS/CdTeS/ZnS quantum dots (QDs) with highly exposed large specific area and energy coupling. The design of the photoanode expressed significant enhanced photoelectrochemical (PEC) performance such as improved absorption efficiency, reduced recombination rate, and enhanced charge transportation state, resulting in a significant increase in photoelectron current. The multinanoheterostructures photoanode provides a high photocatalytic activity and a maximum photocurrent density up to 9.41 mA/cm2 under AM 1.5 G illumination. The novel cosensitized multinanoheterostructures photoanodes lead to a remarkable and promising application in photoelectrochemical and water splitting reactions.

Guided by the hexagonal lattice symmetry, triangles and hexagons are the most basic morphological units for two-dimensional (2D) transition metal dichalcogenides (TMDs) synthesized by chemical vapor deposition (CVD). Also, it is widely acknowledged that these units start from the single nucleation site and then grow epitaxially. Accordingly, the triangular monolayer (ML) samples are generally considered as single crystals. Here, we report a 2D core–shell growth mode in the CVD process for ML-MoS2, which leads to one kind of “pseudo” single-crystal triangles containing triangular outline grain boundaries (TO-GBs). It is difficult to be optically distinguished from the “true” single-crystal triangles. The weakening of Raman peaks and the remarkable enhancement of photoluminescence (PL) are found at the built-in TO-GBs, which could be useful for high-performance optoelectronics. In addition, the electrical measurements indicate that the TO-GBs are conductive. Furthermore, TO-GBs and the common grain boundaries (CO-GBs) can coexist in a single flake, whereas their optical visibility and optical modifications (Raman and PL) are quite different. This work is helpful in further understanding the growth mechanism of 2D TMD materials and may also play a significant role in related nanodevices.Keywords: 2D core−shell growth mode; MoS2; photoluminescence; Raman; TO-GBs;

•Tunable perfect absorber constituted by square graphene-dielectric arrays is proposed and numerically simulated.•Complete graphene layer is utilized in the arrays without demand of cutting into periodic patterns.•The arrays achieve two perfect absorption peaks within a wide range of specific geometric parameters.•Both the two absorption peaks have sensitive response to chemical potential ranging from 0.5 to 1.0 eV.As a two dimensional material with extraordinary optoelectronic properties, graphene has been persistently focused and studied. Inspired by the effects of prominent near-field enhancement and tight field confinement of graphene surface plasmons, tunable perfect absorber constituted by square graphene-dielectric arrays is proposed in this work and investigated with numerical simulation. Complete monolayer graphene is utilized in the arrays, without demand of manufacture process to cut graphene layer into periodic patterns. Within a wide range of specific geometric parameters, the arrays achieve two absorption peaks with near unity absorbance at near-infrared wavelengths. The absorption performance of the arrays is also independent of polarization. It's discovered that surface plasmonic modes are simultaneously excited on graphene and gold-dielectric interface, and there is a strong coupling between such two modes. Moreover, both of the two peaks can be dynamically tuned by adjusting chemical potential of graphene, without salient absorption reduction. With these excellent features, the arrays may provide prospects in development of new sensors and switches.Download high-res image (367KB)Download full-size image

•We successfully fabricate micro-floriated AgBr/Bi2O3 composites by one simple hydrothermal react with precusor BiOBr. This micro-floriated Bi2O3 heterojunction composite is rarely reported by others.•Heterojunction AgBr/Bi2O3 composite exhibits highly efficient photocatalytic activity to decompose pollutant.•The enhanced photocatalytic activity was attributed to the improved visible light harvesting ability and higher separation efficiency of photogenerated electron–hole pairs by the introduction of AgBr.•This composite is beneficial to industrial applications to eliminate the organic pollutants from waste water.Semiconductor with photocatalytic property is the potential solution to solve the problem about water pollution. Novel floriated AgBr/Bi2O3 fabricated through a facile simple two-step hydrothermal method is an efficient photocatalyst. The eminent performance for degradation of methyl orange (MO) was evaluated under visible light irradiation. Many characterization methods, including XPS, XRD, FT-IR, SEM, TEM and UV–vis diffuse reflection spectroscopy, were used to investigate the structure, elemental composition, morphology and catalytic activity. Broad contact between AgBr and Bi2O3 interface enabled hybrid materials possess superior efficiency for the decomposition of MO under visible light irradiation. The optimum photocatalytic activity of samples was approximately 11.7 times higher than pure Bi2O3. In addition, the photo-generated reactive species were identified based on free radicals trapping experiments, which revealed that superoxide radical is the key factor to the photocatalytic process.Download high-res image (123KB)Download full-size image

•Samples possess excellent SH property, i.e. high contact angle (150°) and low roll-off angle (8°).•Fabricate nano-micro surface by one-step procedure, which is green and easy to operate.•SH surfaces show remarkable anti-ice property and stability in acidic and alkaline conditions.•Corrosion resistance capacity of the aluminum and zinc plates was achieved after the treatment.•The procedure can be applied to other metal easily.Superhydrophobic surfaces on metal materials play a significant role in considerable industries because of its eminent water-repel and anti-pollutant ability. A facile green methodology is proposed to in situ fabricate superhydrophobic surface on aluminum surface by simply immersing the plate in an aqueous mixture solution of HCl and stearic acid. Sample possesses high contact angle (150°) and low roll-off angle (8°), because the surface simultaneously combines rough structure with low surface energy. SEM images and contact angle measurements directly show the rough structures and contact angles. It did not require any toxic chemical agents, sophisticated techniques or equipments. The surface modification and ligand bonding of stearic acid on aluminum surface were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. More importantly, the obtained superhydrophobic surfaces show remarkable stability in acidic and alkaline conditions, and the contact angle can stay above 150° without apparent fluctuation for water droplet with pH value ranging from 1 to 14. A prominent enhancement on the corrosion resistance capacity of the aluminum and zinc plates was achieved after the superhydrophobic treatment.

Dust greatly influences the light transmittance of solar panels and their corresponding photovoltaic (PV) performance. However, this critical issue (dust resistance for PV devices) has not been given much attention. In this work, a new self-cleaning coating is proposed to address this problem. The coating consists of patterned scallion-like zinc oxide (ZnO), which is hydrothermally grown on a colloidal monolayer template. The crystallization and fluorescence properties of the scallion-like ZnO are quite good. This self-cleaning coating can reduce the light reflection of the PV device as well as convert the ultraviolet (UV) photons into visible photons, thus reducing light-induced degradation of amorphous silicon PV devices. Also, the surface of this coating possesses superhydrophobic properties, with a water contact angle (CA) larger than 150° and a sliding angle (SA) less than 10°, after modification with heptadecafluorodecyltrimethoxysilane (HTMS). Most importantly, a predictive self-assembly method enabled by Monte Carlo (MC) simulation is developed to obtain a wafer-scale colloidal monolayer consisting of hexagonal-close-packed polystyrene (PS) spheres. This method combines spin-coating with thermal treatment which plays a key role in forming a high-quality colloidal monolayer. As commonly known, identifying the optimized self-assembly temperature through experiments is a great challenge and no studies are located in the literature investigating predictive self-assembly of the colloidal monolayer. Herein, we develop MC simulation to predict the optimized temperature of the colloidal monolayer self-assembly, which can effectively reduce experimental burden, and then fabricate a wafer-scale colloidal monolayer with high quality for the first time.

Attention on semiconductor nanocrystals have been largely focused because of their unique optical and electrical properties, which can be applied as light absorber and luminophore. However, the band gap and structure engineering of nanomaterials is not so easy because of their finite size. Here we demonstrate an approach for preparing ternary AgInS2 (AIS), quaternary AgZnInS (AZIS), AgInS2/ZnS and AgZnInS/ZnS nanocompounds based on cation exchange. First, pristine Ag2S quantum dots (QDs) with different sizes were synthesized in one-pot, followed by the partial cation exchange between In3+ and Ag+. Changing the initial ratio of In3+ to Ag+, reaction time and temperature can control the components of the obtained AIS QDs. Under the optimized conditions, AIS QDs were obtained for the first time with a cation disordered cubic phase and high photoluminescence (PL) quantum yield (QY) up to 32% in aqueous solution, demonstrating the great potential of cation exchange in the synthesis for nanocrystals with excellent optical properties. Sequentially, Zn2+ ions were incorporated in situ through a second exchange of Zn2+ to Ag+/In3+, leading to distinct results under different reaction temperature. Addition of Zn2+ precursor at room temperature produced AIS/ZnS core/shell NCs with successively enhancement of QY, while subsequent heating could obtain AZIS homogeneous alloy QDs with a successively blue-shift of PL emission. This allow us to tune the PL emission of the products from 483 to 675 nm and fabricate the chemically stable QDs core/ZnS shell structure. Based on the above results, a mechanism about the cation exchange for the ternary nanocrystals of different structures was proposed that the balance between cation exchange and diffusion is the key factor of controlling the band gap and structure of the final products. Furthermore, photostability and in vitro experiment demonstrated quite low cytotoxicity and remarkably promising applications in the field of clinical diagnosis.Keywords: alloy; band and structure engineering; cation exchange; core/shell; nanocrystals; targeted labeling

The issue of oil/water separation has recently become a global concern due to the frequency of oil spills and the increase in industrial waste water. Thus, membrane-based materials with unique wettability are desired to separate both of these from a mixture. Nevertheless, the fabrication of energy efficient and stable membranes appropriate for the separation process remains challenging. Herein, synergistic superhydrophilic–underwater superoleophobic inorganic membranes were inventively created by a maneuverable galvanic displacement reaction on copper mesh. The “water-loving” meshes were then used to study gravity driven oil–water separation, where a separation efficiency (the ratio of the amount of oil remaining above the membrane after the separation process to the amount of oil in original mixture) of up to 97% was achieved for various oil–water mixtures, and furthermore the wetting properties and separating performances were maintained without further attenuation after exposure to corrosive environments. Notably, the “repelling-oil” mode can switch to a superhydrophobic mode which acts as a supplementary “oil slick absorbing” material floating above the water surface and has potential in tackling oil slick clean-up issues, in comparison to the former mode which possesses better “separation ability”. In addition, the original “repelling-oil” state can be reinstated with ease. The novel method involving a “one-cyclic transformation course” abandons extra chemical addition. The facile and green route presented here acts as an excellent test for the fabrication of a dual-functioning membrane with potential use in efficient oil–water separation, even in harsh environments, and off-shore oil spill cleanup.

•Potential of ZnTiO3 photoanode was predicted on theory for the first time.•QDSSC of ZnTiO3/CdS/CdSe was synthesized for the first time.•Optimal grown times of different quantum dots were meticulously researched.•Comparisons with other emerging photoanodes were carefully made.For the first time, ZnTiO3 applied as an innovative photoanode material in quantum-dot-sensitized solar cells (QDSSCs) has been systematically researched both theoretically and experimentally in this paper. The electron mobility (150–400 cm2/vs) of this material, achieved via the deformation potential theory, is much higher than that of most known photoanodes, including TiO2 and ZnO which have been heavily researched. The preparation of QDSSCs with the structure of ZnTiO3/CdS/CdSe yielded a high energy conversion efficiency of 1.95% and a large short-circuit current density of 5.96 mA/cm2, which are also superior to the characteristics of other emerging photoanode materials, such as SnO2, Zn2SnO4, BaTiO3, and so on, indicating the good potential of this material for using in QDSSCs.

As a rising star in two-dimensional (2D) layered materials, transition metal dichalcogenides (TMDs) have attracted tremendous attention for their potential applications in nanoelectronics, optoelectronics and photonics. Driven by the high standards of practical devices, alloying theory has been proposed for modulating the electronic structure of TMDs materials as well as their physical and chemical properties. To date, however, very limited alloy materials can be synthesized by chemical vapor deposition (CVD) and a very limited band gap range can be achieved. Herein, for the first time, we report a one-step CVD strategy for the growth of ternary alloy Mo(1−x)WxS2 monolayers (ML) on SiO2/Si substrates with controllable composition. Both Mo(1−x)WxS2 and MoS2(1−x)Se2x alloy materials with high crystallinity were synthesized in this study. Therefore, the bandgap photoluminescence (PL) can be broaden from 1.97 eV (for ML-WS2) to 1.55 eV (for ML-MoSe2). Furthermore, density functional theory calculations were performed to reveal the important role of alloying in tailoring the electronic structure of 2D materials.

Cu doped Zn–In–S quantum dots (CZIS QDs) were synthesized by a hydrothermal method. The absorption and fluorescence peaks of CZIS QDs shifted monotonically to longer wavelengths with the increase of the Cu precursor and the decrease of Zn and In precursors. The dopant emission wavelength can be easily tuned in the whole visible region ranging from 465 nm to 700 nm by changing the molar ratio of Cu/Zn/In/S. On the basis of experimental results, it was testified that the emission of CZIS QDs was the trap state emission rather than the excitonic emission. The emission mechanisms of CZIS QDs were attributed to three kinds of approaches: (i) photogenerated holes efficiently move to trap states induced by Cu defects and recombine with the electrons in the energy level of sulfur vacancies; (ii) the holes in Cu trap states recombine with the electrons in the surface defect state; (iii) the electrons in the conduction band recombine with the holes in levels caused by Zn vacancies. After coating the ZnS shell around the CZIS core, the fluorescence quantum yield of CZIS QDs can reach 25–35%. CZIS/ZnS QDs conjugated with antibodies were successfully applied for labeling Hep-G2 liver cancer cells. The cytotoxicity studies revealed that the viabilities of the cells incubated with different concentrations of CZIS/ZnS QDs and at different times all remained at a high level of more than 90%. Hence, the CZIS/ZnS nanoparticle is a promising material as the fluorescent probe for biological applications.

Despite the fact that Au–Ag hollow nanoparticles (HNPs) have gained much attention as ablation agents for photothermal therapy, the instability of the Ag element limits their applications. Herein, excess Au atoms were deposited on the surface of a Au–Ag HNP by improving the reduction power of l-ascorbic acid (AA) and thereby preventing the reaction between HAuCl4 and the Ag element in the Au–Ag alloy nanostructure. Significantly, the obtained Au–Ag@Au HNPs show excellent chemical stability in an oxidative environment, together with remarkable increase in extinction peak intensity and obvious narrowing in peak width. Moreover, finite-difference time-domain (FDTD) was used to simulate the optical properties and electric field distribution of HNPs. The calculated results show that the proportion of absorption cross section in total extinction cross section increases with the improvement of Au content in HNP. As predicted by the theoretical calculation results, Au–Ag@Au nanocages (NCs) exhibit a photothermal transduction efficiency (η) as high as 36.5% at 808 nm, which is higher than that of Au–Ag NCs (31.2%). Irradiated by 808 nm laser at power densities of 1 W/cm2, MCF-7 breast cancer cells incubated with PEGylated Au–Ag@Au NCs were seriously destroyed. Combined together, Au–Ag@Au HNPs with enhanced chemical stability and improved photothermal transduction efficiency show superior competitiveness as photothermal agents.Keywords: absorption; alloy; hollow nanostructure; photothermal therapy; stability

Here we demonstrate a novel and facile strategy of highly luminescent water-soluble Zn-doped AgIn5S8 (ZAIS) nanocrystals and ZAIS/ZnS core/shell structures, which were based on hydrothermal reaction between the acetate salts of the corresponding metals and sulfide precursor in the presence of l-cysteine at 110 °C in a Teflon-lined autoclave. The photoluminescent (PL) emission wavelength can be conveniently tuned from 560 to 650 nm by tailoring the stoichiometric ratio of [Ag]/[Zn]. The as prepared nanocrystals were characterized systematically and exhibit long PL lifetimes more than 100 ns. The influence of experimental conditions, including concentration of l-cysteine and reaction temperature, was investigated. In addition, we performed a coating procedure with the ZnS shell outside the ZAIS core and showed excellent PL quantum yields up to 35%. The in vitro experiment exhibited quite low cytotoxicity and marvelous biocompatibility, revealing their promising prospect in bioscience. Furthermore, the obtained ZAIS/ZnS nanocompounds (NCs) were covalently conjugated to alpha-fetoprotein antibodies and targeted fluorescent imaging for hepatocellular carcinoma cells was realized.

Superhydrophobic surfaces were prepared on Cu substrates via a facile surface oxidation approach and subsequent chemical modification with low surface energy materials. In this paper, antiformin solution, as one of the most commonly used low cost disinfectants, is introduced for preparing bionic microstructures on copper surfaces for the first time. A short-time oxidation reaction soaking the Cu foil in antiformin liquid can result in the formation of a bean sprout-like structure. Moreover, regulating the morphology of the microstructure can be realized by changing the reaction duration and solution concentration under a wide range of experimental conditions. A possible growth mechanism is also proposed here. After being modified by stearic acid, all as-etched surfaces possess superhydrophobic properties, with a water contact angle (CA) larger than 150° and a sliding angle (SA) less than 10°. Simultaneously superoleophobic interfaces can be obtained after the etched surfaces are modified with heptadecafluorodecyltrimethoxysilane (HTMS). The resultant samples present good thermal stability at ambient temperatures below 150 °C. The same approach is also suitable for brass materials. This offers an effective and practical route for large scale industrial production of superhydrophobic materials.

•A new mechanism for enhancing fluorescence is proposed.•A new versatile method is developed to achieve engineered fluorescence.•FDTD simulation is employed to reveal plasmonics spots.•It is the first time to incorporate QDs into the spherical triangle gold arrays.•Engineered fluorescence is demonstrated via the resultant plasmonic nanostructures.Engineered metallic nanostructures, namely, plasmonic nanostructures, have broad application prospects. Herein, we develop a versatile and reliable method, which combines slope self-assembly colloidal crystal with metal deposition, to harvest the engineered metallic nanostructures. The method possesses the advantages of low-cost, high sample output and being compatible with industrial process. Colloidal semiconductor quantum dots (QDs) are integrated within pre-designed engineered metallic nanostructures. Impressed results (an approximate 15 fold increase of photoluminescence intensity), have been realized. Moreover, field distribution of the periodic metal nanostructures is simulated via finite-difference time domain (FDTD). Importantly, a new mechanism, in addition to conventional theory, is proposed to illustrate the large enhancement of fluorescence efficiency. Additionally, engineered fluorescence, including controlled emission linewidth, peak and intensity, is achieved through the coupling of engineered metallic nanostructures and QDs. It is demonstrated that plasmonic nanostructures and engineered fluorescence has the potential to provide promise for a range of applications, including solar cell, light-emitting diodes, and single-molecule studies.

In this paper, we innovatively propose a facile and controllable way to prepare a superhydrophobic Zn/ZnO film on a zinc substrate. In this approach, we soak the acid etched Zn substrate in pure warm water, resulting in the formation of a hierarchical configuration with micron-sized grooves and nanorods. The lotus-like hierarchical Zn/ZnO micro/nano structure can be acquired and tailored under a wide range of reaction conditions by controlling the reaction temperature and duration. The formation mechanism of the hierarchical structure has been discussed. The wettability of as-modified surfaces has been studied through three aspects: superhydrophobicity, oleophobicity (for oily liquids), and oil–water separation properties. What's more, the as-prepared superhydrophobic samples show good thermal stability (under 200 °C) and recoverability. This approach offers potential for industrial application of self-cleaning surfaces because of its features such as time-saving, low cost, easy preparation and so on.

Hydrofluoric acid (HF)-assisted one-step synthesis of pompon-like/chip-like FeSe2 particles by a solvothermal method has been studied for the first time in this paper. By adjusting the dosage of HF used, FeSe2 particles with pompon-like and chip-like morphologies were obtained. The reaction mechanism was presented based on the experimental phenomena, and the roles played by HF in the synthesis were clearly explained, proving that HF had a significant influence on controlling the morphologies of the FeSe2 particles. By altering the iron sources without changing any other conditions (similar experimental results were observed). We further demonstrated that this method was universally applicable. The wettability and light-trapping effects of the pompon-like/chip-like particles were also investigated, respectively. After modification with heptadecafluorodecyltrimethoxy-silane (HTMS), the pompon-like particles exhibited excellent superhydrophobic/superoleophobic (superamphiphobic) properties with water/oil contact angle of about 156.0°/154.6° and water/oil sliding angle of about 2.0°/5.0°. Ultralow reflectance of the samples (lower than 3%) in the entire wavelength range of 300–1800 nm was also observed in our experiments. Utilizing HF to control the morphologies of FeSe2 particles is an innovative attempt and is expected to show promising potential in controlling the morphologies of other transition metal chalcogenides.

Au nanoparticle@SiO2@CdTe/CdS/ZnS quantum dot (QD) composite structures were synthesized by a liquid phase synthesis method. In this paper, three steps were adopted to gradually grow PVP-stabilized Au seeds from which PVP-stabilized Au nanoflower (NF) structures were successfully synthesized. For the sake of controlling the distance between Au NFs and QDs, silica was used as the shell material for coating Au NFs. The applications of this multi-functional nanoprobe in photothermal treatment and bio-labeling were demonstrated on MCF-7 and MDA-MB-231 breast cancer cells labeled with Au NF@SiO2@QDs. The experimental results of viability staining indicate that Au NF@SiO2@QDs composites with an excitation threshold of the photothermal effect of only 1.0 W cm−2 exhibit excellent photothermal conversion efficiency owing to the large absorption cross sections of Au NFs. Compared with that of pure QDs, the fluorescence efficiency of Au NF@SiO2@QDs was increased by 40%, which could be attributed to localized surface plasmon enhanced dipole radiation. Fluorescence imaging results reveal that Au NF@SiO2@QDs targeted the membrane of cancer cells showing strong fluorescence. Therefore, it can be concluded that the composite structure combines the therapeutic and diagnostic modalities.

We present a new style extraordinary optical transmission (EOT) nano optical filter combined by two kinds of subwavelength holes array on a gold film. In the design, a square array of non-penetrating holes (hollow holes) inlays into another square array of penetrating holes ordered by a central arrange mode. We numerically calculated the transmission spectra of the patterned gold films by finite-difference time-domain (FDTD) method. Results show that the transmission of the filter can be manipulated by changing the depth of non-penetrating holes. The (1, 1) peak can be enhanced when the incident light normally illuminates one side of the filter with the hollow holes, yet the (1, 1) peak can be suppressed when the light illuminates the other side without hollow holes. It also depicts that the hollow hole array results in energy level splitting of (1, 0) mode propagating on the surface of the filter. What’s more, the splitting can be eliminated by modulating the depth of the hollow holes. Our study further reveals the role of suface plasmon effect in the EOT.

•Silver nanosphere with good homogeneity and dispersity was synthetized.•The enhancement ratio was relative to the thickness of dye-doped silica layer.•The strongest fluorescence signal obtained as dye-SiO2 layer tuned to 10 nm.•An 11-fold enhancement was realized, compared with the sample without silver core.Enhancement of the light emission of dye molecules (Ru(bpy)32+) was studied by coating dye-doped SiO2 layer on Ag core. The enhancement ratio was found to be relative to the thickness of dye-doped silica layer. The core–shell Ag@dye-SiO2 nanocomposites have the strongest fluorescence intensities when the thickness of dye-SiO2 layer was tuned to 10 nm. It was found that an 11-fold enhancement of fluorescence signal was realized with Ag@dye-SiO2 nanoparticles, compared to the sample without silver core.Graphical abstract

We developed a simple and general approach for constructing a wafer-scale monolayer, close-packed polystyrene (PS), and SiO2 sphere arrays, namely colloidal crystals, which have significant potential in various applications. The method combines slope self-assembly and thermal treatment to achieve large-area and high-quality colloidal crystal with a proper slant angle (θ) and latex concentration (volume fraction, φ). The dependence of the structures of colloidal crystals on a dispersion system was also investigated. Moreover, a theoretical analysis of the slope self-assembly method was proposed. In addition, we applied the method to assemble PS spheres on different kinds of substrates, which indicates that the method is a versatile and reliable way to fabricate monolayer colloidal crystals.

An electrolysis method for preparation of Ag nanoparticle (NP) films on the transparent conductive substrates was developed. The morphologies and sizes of Ag NPs can be controlled by the electrolysis time and thermal treatment modes. The enhancement of photoluminescence from CdSe quantum dots due to the localized surface plasmons (LSPs) of Ag nanoparticles was also investigated. The strongest enhancement is as high as 10 times. Additionally, the effect of thermal treatment process, including the rapid thermal treatment and slow thermal process, on the morphology of the Ag nanoparticle was also studied. The result shows that the slow thermal treatment process would be favorable for the formation of larger Ag NPs and increasing the ratio of worm-like Ag NPs, which contain most of the “hot spots”, increases the quantum yields of LSPs.Highlights► We developed an electrolysis method to prepare Ag nanoparticle (NP) films. ► Ag NP morphology and size are controlled by electrolysis time and thermal treatment modes. ► Worm-like Ag NPs lead to stronger photoluminescence enhancement in CdSe/Ag system.

Enhancement of the light emission of CdSe quantum dots was observed by coupling through localized surface plasmons from Au nanoparticles. The enhancement was found to be relative to the shapes and sizes of Au nanoparticles. Au nanoparticles of different sizes were synthesized by a citrate-seeded method. By varying the annealing temperature, worm-like Au nanoparticles of different aspect ratios from 1 to 5 were obtained. Samples of the CdSe coupled with Au with an aspect ratio of 2 and annealed at 500 °C exhibited the best photoluminescence emission efficiency. Furthermore, a stronger photoluminescence enhancement was observed with increasing the size of Au nanoparticles. It was also found that when the localized surface plasmons resonance absorption wavelength of Au nanopartiles was just a little smaller than the emission peak of CdSe, the CdSe quantum dots exhibited the strongest photoluminescence intensity, with an enhancement of 6 times.

Localized surface plasmon resonance (LSPR) enhanced photoluminescences (PL) from CdSe quantum dots (QDs) on worm-like or quasi-spherical silver colloids have been investigated. The shape of silver colloid film is controlled by annealing temperature (200 °C∼350 °C). Strong PL enhancements of CdSe QDs on both as-grown and annealed silver colloid films are observed. The results show that the PL enhancement factor of CdSe QDs on worm-like silver colloid film reaches as high as 15-fold. Moreover, the enhancement factor is 5 times larger than that obtained from the quasi-spherical silver colloids. The superiority of worm-like silver nanostructure on LSPR enhanced photoluminescence is attributed to its larger size, hot spots and multiple dipole resonance modes coupling, which are induced by aggregation effect.

We present a hydrothermal approach for the preparation of biocompatible and high-quality Zn3In2S6 (ZIS) quantum dots (QDs) in the presence of glutathione (GSH) as a stabilizer at different reaction temperatures. The as-prepared QDs exhibited small particle diameters (from 3.3 to 7.5 nm) with a hexagonal structure and size-dependent optical properties. The combination of the pH value and the amount of GSH played a crucial role in the enhancement of PL intensity. After the incorporation of Ag via cation exchange, the obtained Ag–Zn–In–S (AZIS) QDs demonstrated both red-shifted photo-luminescence (PL) emission and higher quantum yield. Furthermore, based on the investigations of PL lifetimes and excitation intensity-dependent PL spectra, we concluded that PL emission of ZIS QDs originated from shallow donor–acceptor (D–A) pair recombination, and intrinsic trap state-related deep D–A pair transition dominated the main emission of AZIS QDs. Furthermore, the biocompatible AZIS QDs with high quantum yield were applied to targeted labeling and imaging in the cytoplasm of hepatocellular carcinoma cells, indicating their promising applications in single-cell monitoring.

The issue of oil/water separation has recently become a global concern due to the frequency of oil spills and the increase in industrial waste water. Thus, membrane-based materials with unique wettability are desired to separate both of these from a mixture. Nevertheless, the fabrication of energy efficient and stable membranes appropriate for the separation process remains challenging. Herein, synergistic superhydrophilic–underwater superoleophobic inorganic membranes were inventively created by a maneuverable galvanic displacement reaction on copper mesh. The “water-loving” meshes were then used to study gravity driven oil–water separation, where a separation efficiency (the ratio of the amount of oil remaining above the membrane after the separation process to the amount of oil in original mixture) of up to 97% was achieved for various oil–water mixtures, and furthermore the wetting properties and separating performances were maintained without further attenuation after exposure to corrosive environments. Notably, the “repelling-oil” mode can switch to a superhydrophobic mode which acts as a supplementary “oil slick absorbing” material floating above the water surface and has potential in tackling oil slick clean-up issues, in comparison to the former mode which possesses better “separation ability”. In addition, the original “repelling-oil” state can be reinstated with ease. The novel method involving a “one-cyclic transformation course” abandons extra chemical addition. The facile and green route presented here acts as an excellent test for the fabrication of a dual-functioning membrane with potential use in efficient oil–water separation, even in harsh environments, and off-shore oil spill cleanup.

Superhydrophobic surfaces were prepared on Cu substrates via a facile surface oxidation approach and subsequent chemical modification with low surface energy materials. In this paper, antiformin solution, as one of the most commonly used low cost disinfectants, is introduced for preparing bionic microstructures on copper surfaces for the first time. A short-time oxidation reaction soaking the Cu foil in antiformin liquid can result in the formation of a bean sprout-like structure. Moreover, regulating the morphology of the microstructure can be realized by changing the reaction duration and solution concentration under a wide range of experimental conditions. A possible growth mechanism is also proposed here. After being modified by stearic acid, all as-etched surfaces possess superhydrophobic properties, with a water contact angle (CA) larger than 150° and a sliding angle (SA) less than 10°. Simultaneously superoleophobic interfaces can be obtained after the etched surfaces are modified with heptadecafluorodecyltrimethoxysilane (HTMS). The resultant samples present good thermal stability at ambient temperatures below 150 °C. The same approach is also suitable for brass materials. This offers an effective and practical route for large scale industrial production of superhydrophobic materials.

Dust greatly influences the light transmittance of solar panels and their corresponding photovoltaic (PV) performance. However, this critical issue (dust resistance for PV devices) has not been given much attention. In this work, a new self-cleaning coating is proposed to address this problem. The coating consists of patterned scallion-like zinc oxide (ZnO), which is hydrothermally grown on a colloidal monolayer template. The crystallization and fluorescence properties of the scallion-like ZnO are quite good. This self-cleaning coating can reduce the light reflection of the PV device as well as convert the ultraviolet (UV) photons into visible photons, thus reducing light-induced degradation of amorphous silicon PV devices. Also, the surface of this coating possesses superhydrophobic properties, with a water contact angle (CA) larger than 150° and a sliding angle (SA) less than 10°, after modification with heptadecafluorodecyltrimethoxysilane (HTMS). Most importantly, a predictive self-assembly method enabled by Monte Carlo (MC) simulation is developed to obtain a wafer-scale colloidal monolayer consisting of hexagonal-close-packed polystyrene (PS) spheres. This method combines spin-coating with thermal treatment which plays a key role in forming a high-quality colloidal monolayer. As commonly known, identifying the optimized self-assembly temperature through experiments is a great challenge and no studies are located in the literature investigating predictive self-assembly of the colloidal monolayer. Herein, we develop MC simulation to predict the optimized temperature of the colloidal monolayer self-assembly, which can effectively reduce experimental burden, and then fabricate a wafer-scale colloidal monolayer with high quality for the first time.

Cu doped Zn–In–S quantum dots (CZIS QDs) were synthesized by a hydrothermal method. The absorption and fluorescence peaks of CZIS QDs shifted monotonically to longer wavelengths with the increase of the Cu precursor and the decrease of Zn and In precursors. The dopant emission wavelength can be easily tuned in the whole visible region ranging from 465 nm to 700 nm by changing the molar ratio of Cu/Zn/In/S. On the basis of experimental results, it was testified that the emission of CZIS QDs was the trap state emission rather than the excitonic emission. The emission mechanisms of CZIS QDs were attributed to three kinds of approaches: (i) photogenerated holes efficiently move to trap states induced by Cu defects and recombine with the electrons in the energy level of sulfur vacancies; (ii) the holes in Cu trap states recombine with the electrons in the surface defect state; (iii) the electrons in the conduction band recombine with the holes in levels caused by Zn vacancies. After coating the ZnS shell around the CZIS core, the fluorescence quantum yield of CZIS QDs can reach 25–35%. CZIS/ZnS QDs conjugated with antibodies were successfully applied for labeling Hep-G2 liver cancer cells. The cytotoxicity studies revealed that the viabilities of the cells incubated with different concentrations of CZIS/ZnS QDs and at different times all remained at a high level of more than 90%. Hence, the CZIS/ZnS nanoparticle is a promising material as the fluorescent probe for biological applications.