Exfoliation and functionalisation of two-dimensional (2D) nanosheets are highly desired for the improvement of their chemical and physical properties. Herein, we propose a novel and efficient method for the preparation of fluorinated graphite carbon nitride (F-C3N4) nanosheets with enhanced photocatalytic activities. A one-step route was used to exfoliate and fluorinate the graphite carbon nitride (g-C3N4) nanosheets by using g-C3N4 powder combined with ammonium fluoride (NH4F). Through related instrumental characterisation, we confirmed that few-layered F-C3N4 nanosheets were produced successfully. Meanwhile, the enhanced hydrogen evolution rate of F-C3N4 nanosheets (477.6 µmol h−1 g−1) also confirmed the feasibility of this exfoliation method. This report not only opens up new possibilities for the rational design of metal-free F-C3N4 nanosheets with stable photochemical applications but also provides a potential method for producing functionalised 2D materials.

With hydrogen storage methods advancing, “hydrogen economy” has been attracting considerable attention from scientists. It is therefore essential to develop efficient and stable methods for photocatalytic hydrogen evolution (PHE). Although some photocatalysts are highly efficient, they often contain noble or heavy metals, which are either expensive or not environmentally friendly. Therefore, fabricating economical and environmental-friendly photocatalysts is still a challenge. ZnS is an inefficient photocatalyst for hydrogen evolution due to its inability to absorb light at wavelengths longer than the ultraviolet range of the solar spectrum, a high recombination rate for photoinduced electron–holes, and photocorrosion as a result of photogenerated holes. WS2 nanosheets are known as excellent cocatalysts. Herein, we report the first demonstration of ZnS/WS2 nanosheet-composites (several layers) for use as economical and environmental-friendly photocatalysts. Combining ZnS with WS2 nanosheets together can broaden the absorption spectrum and improve the electron–hole pairs separation efficiency. WS2 nanosheets serve as an electron transporter, PHE activity sites, and also a ZnS nanoparticle immobilization scaffold in the composite. The PHE activity of ZnS/WS2 nanocomposite is three times higher than that of pure ZnS nanoparticles under Xe lamp (300 W) irradiation, and the catalyst shows excellent photostability. The strategy presented in this study may have potential use in fabricating economical and environmental-friendly photocatalysts.

Efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) are central to the development of renewable energy. In this study, a photoresponse electrocatalyst Ni3(VO4)2 with a sea-urchin shaped structure was prepared by a facile solvothermal procedure. Numerous thin nanoflakes on the spherical surface increased active sites which play a promoting role in the photocatalytic or electrocatalytic reactions. Under visible light irradiation, the sea-urchin shaped Ni3(VO4)2 demonstrated improved HER activity without using any cocatalysts, featured by a small overpotential of −90 mV at 10 mA cm−2, a high current density, a small Tafel slope of 50 mV per decade and good stability in 0.5 M H2SO4. The results may offer a simple and mild methodology for the preparation of HER electrocatalysts exhibiting excellent photo-enhanced electrocatalytic activity.

Novel UV and visible light photocatalytic carbon dots/BiOBr nanocomposites were prepared for the first time. The structures, morphologies, optical, photoelectrochemical and photocatalytic properties were investigated. The results indicated that the carbon dots (CDs) combined well with BiOBr. An appropriate amount of introduced CDs can significantly enhance the photocatalytic activities under both UV and visible light irradiation. The enhanced activities were mainly attributed to the enhanced light absorption and the interfacial transfer of photogenerated electrons. The corresponding photocatalytic mechanism was proposed based on the results.

Highly biocompatible near-infrared-emitting CdSeTe alloyed quantum dots (QDs) were fabricated in aqueous medium with octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) as the capping agent. By changing the size and composition of CdSeTe alloyed QDs the fluorescence emission peak reached the near infrared (NIR) region (681 nm) with a photoluminescent quantum yield (QY) of 26.4%. POSS–CdSeTe QDs were prepared by conjugating OA-POSS to CdSeTe QDs through condensation reaction utilizing EDC. And the optical properties of CdSeTe QDs were retained with improved biocompatibility. Furthermore, the as-prepared NIR-emitting POSS–CdSeTe alloyed QDs have been successfully applied to SiHa cell imaging, which demonstrates their promising applications in the biomedical field.

A series of reduced graphene oxide and CdS nanocomposites (RGO–CdS) with different weight ratios of RGO have been synthesized by a facile microwave-assisted solvothermal method, in which the room temperature ionic-liquid 1-butyl-3-methylimidazolium thiocyanate ([BMIM]·SCN) served as sulfur source as well as stabilizing agent. RGO sheets were uniformly decorated by CdS nanospheres in the as-prepared samples. Only aggregates of CdS particles over 100 nm were obtained, when graphene oxides were not employed. The existence of RGO could effectively enhance the photocatalytic activity for the degradation of rhodamine B (RhB) under visible light irradiation and the RGO–CdS-10% sample possessed the highest activity and excellent stability. The improved photocatalytic efficiency of RGO–CdS nanocomposites could be attributed to the enhanced adsorbability of RhB molecules, a broadened light response range in the visible spectrum and improved separation efficiency of electron–hole pairs, all of which result from the introduction of RGO. It is hoped that this facile and efficient synthesis route can promote the exploration and utilization of graphene-based semiconductor nanocomposites as visible-light photocatalysts.

The CdTe QDs coated by octa-mercaptopropyl polyhedral oligomeric silsesquioxane (OM-POSS) were successfully applied in cell labeling as a fluorescent probe. SiHa cells and mouse preosteoblast cells MC3T3-E1 were employed to evaluate the cell toxicity of the POSS-CdTe QDs and CdTe QDs. The cells incubated with POSS-CdTe QDs show higher viability than those with CdTe QDs under the same conditions. More POSS-CdTe QDs are internalized into cells via endocytosis than CdTe QDs during the same incubation time, which is vividly exhibited in laser confocal images. The highly biocompatible CdTe QDs with amphiphilic OM-POSS coating allow rapid intracellular uptake, enabling the use of lower concentrations of QDs for an overall reduced toxicity. The as-prepared POSS-CdTe QDs have enormous potential for long-term live cell and in vivo imaging applications.

CdTe quantum dots coated by octamercaptopropyl polyhedral oligomeric silsesquioxane (OM-POSS) were applied to detect trace Cu2+. This detection method is based on selectively quenching the fluorescence originating from the CdTe QDs in the presence of Cu2+. The research showed a low interference response of the POSS-coated CdTe QDs towards other metal ions. The POSS-coated CdTe QDs obtained a higher sensitivity than NAC-coated CdTe QDs. The quenching mechanism is discussed on the basis of the competitive binding of the thiol groups of the OM-POSS between the CdTe QDs and the metal ions. The Stern–Volmer plots at different temperatures show that the fluorescence of the POSS-coated CdTe QDs was quenched by Cu2+ through a static quenching mechanism. The response of the QDs fluorescence intensity is linearly proportional to the Cu2+ concentration ranging from 1 × 10−8 to 1 × 10−6 mol L−1 with a detection limit of 2.3 × 10−9 mol L−1. Furthermore, the method has been successfully applied to the detection of Cu2+ in water samples.

Owning many peculiar properties, hexagonal boron nitride nanosheets (BNNSs) have lots of potential applications, such as electronic devices and deep ultraviolet emitters. In this article, a chemical exfoliation method to prepare few-layer and large size BNNSs is reported. Through related instrument characterizations, we demonstrated that this preparation method can allow the exfoliation of BNNSs from bulk BN powder successfully. From CL spectra, the as-prepared BNNSs were proved to show stronger CL emission ability than BN powder. Based on the experiment results analysis, we proposed an exfoliation mechanism and verified it through in situ SEM detection.

A low cost and simple route was presented to fabricate large-scale ordered microlens arrays on gallium phosphide light emitting diodes with enhanced extraction efficiency. The different morphological microlens arrays were simply fabricated by controlling heat treatment temperature. Light extraction efficiency and light output power of gallium phosphide light emitting diodes were enhanced by different array structures of the polystyrene microlens. Compared to conventional gallium phosphide light emitting diodes, light intensity of the light emitting diodes covered by hemispherical polystyrene microlens shows 1.32 times enhancement under the forward current of 20 mA. The mechanism of enhanced light output with microlens arrays is discussed in detail.

In this paper, a microwave-assisted synthesis method has been used to prepare highly luminescent GSH-capped Zn1−xCdxTe alloyed quantum dots, with pollutant-free sodium tellurite (Na2TeO3) as the Te source. The size and composition-dependent absorption and photoluminescence spectra of the as-prepared alloyed QDs can be tuned from 500 nm to 610 nm, and the photoluminescent quantum yield of our synthesized alloyed QDs can reach up to 90%. The in vitro cytotoxicity studies (MTT-assay) demonstrate that the cytotoxicity of the GSH-capped Zn1−xCdxTe alloyed QDs can be reduced to a small extent due to the incorporation of the Zn ions. Green emitting GSH-capped Zn1−xCdxTe alloyed QDs are successfully used for A549 cellular imaging on a laser scanning confocal microscopy. Our systematic investigation clearly shows that these high-performance Zn1−xCdxTe alloyed QDs are highly promising biological fluorescent labels in biological applications.

TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells and photocatalysis. In this paper, single-crystalline rutileTiO2 nanorod arrays were fabricated on the GaN based light emitting diodes (LEDs) with a TiO2 seed layer by an acid hydrothermal process. The morphologies and the crystallinity of the rutileTiO2 nanorod arrays on GaN wafer were characterized by scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction. The optical properties of surface-textured TiO2/GaN were measured and analyzed by photoluminescence. The influence and dependence of the TiO2 nanorod array with the different densities and diameters on the light output of the fabricated GaN wafers were investigated. The light extraction efficiency of GaN LEDs was enhanced by the single-crystalline rutileTiO2 nanorod array, which showed an eight-fold increase in photoluminescence intensity compared to the normal planar surface. The mechanisms for the enhanced light output of GaN LEDs by the single-crystalline rutileTiO2 nanorod arrays were discussed.

Uniform and well-dispersed Y2O3:Eu/YVO4:Eu composite microspheres were prepared by hydrothermal chemical corrosion Y2O3:Eu microspheres with Na3VO4 solution. Effects of pH, molar ratio of Na3VO4 to the Y2O3:Eu precursor (R), and reaction time (t) on the morphology and the crystal structure of the composite were investigated in detail. The photoluminescence intensity of the products synthesized under the optimum condition was much higher than that of the YVO4:Eu nanocrystals prepared by direct hydrothermal method and comparable to that of the bulk YVO4:Eu.Graphical abstractUniform and well-dispersed Y2O3:Eu/YVO4:Eu composite microspheres were prepared by hydrothermal chemical corrosion Y2O3:Eu precursor with Na3VO4 solution. The luminescence intensity of the composite is much higher than that of YVO4:Eu nanocrystals prepared by direct hydrothermal method and closed to that of the bulk YVO4:Eu.Highlights► Y2O3:Eu microspheres acted as precursor. ► Y2O3:Eu/YVO4:Eu microspheres were prepared by chemical corrosion approach. ► The composite microspheres exhibited much high luminescence intensity.

Water-soluble CdTe QDs modified by thioglycolic acid were synthesized with a facile one-pot method. Two-photon excited fluorescence spectroscopic technique was used to study the interaction between TGA-capped CdTe quantum dots and folic acid. Experiments results showed that the two-photon fluorescence of TGA-capped CdTe QDs in PBS buffer solution was quenched in the presence of folic acid. A good linear relationship was observed between the two-photon fluorescence intensity of TGA-capped CdTe QDs and the concentration of folic acid. The two-photon excited fluorescence quenching mechanism was also presented.Highlights► Two-photon excited fluorescence has minimum autofluorescence interference. ► The technique has wider linear range of detecting FA. ► The technique has better precision. ► Application of two-photon excited fluorescence broadens.

We have investigated the catalytic effect of boron nitride (h-BN) nanoparticles. The experiments prove that p-terphenyl can be synthesized from benzene at 400 °C in the presence of h-BN nanoparticles, thereby implying that the observed catalytic property of the h-BN nanoparticles may expand the application field of inorganic nanocrystals. The paper also discusses the mechanism of the structural rearrangement and oligomerization from benzene to p-terphenyl.

A distorted honeycomb-like cadmium–thiocyanate framework with the formular [BMIM]2[Cd2(SCN)6] has been synthesized by self-assembling through electrostatic interaction between cadmium–thiocyanate network and N,N′-dialkylimidazolium ions. The [BMIM]+ cations acting as the spacers and controllers dominate the dimension of the complex.A distorted honeycomb-like cadmium-thiocyanate framework with the formular [BMIM]2[Cd2(SCN)6] has been synthesized by self-assembling through electrostatic interaction between cadmium–thiocyanate network and N,N′-dialkylimidazolium ions. The [BMIM]+ cations acting as the spacers and controllers dominate the dimension of the complex.

CdTe quantum dots coated by octamercaptopropyl polyhedral oligomeric silsesquioxane (OM-POSS) were applied to detect trace Cu2+. This detection method is based on selectively quenching the fluorescence originating from the CdTe QDs in the presence of Cu2+. The research showed a low interference response of the POSS-coated CdTe QDs towards other metal ions. The POSS-coated CdTe QDs obtained a higher sensitivity than NAC-coated CdTe QDs. The quenching mechanism is discussed on the basis of the competitive binding of the thiol groups of the OM-POSS between the CdTe QDs and the metal ions. The Stern–Volmer plots at different temperatures show that the fluorescence of the POSS-coated CdTe QDs was quenched by Cu2+ through a static quenching mechanism. The response of the QDs fluorescence intensity is linearly proportional to the Cu2+ concentration ranging from 1 × 10−8 to 1 × 10−6 mol L−1 with a detection limit of 2.3 × 10−9 mol L−1. Furthermore, the method has been successfully applied to the detection of Cu2+ in water samples.

TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells and photocatalysis. In this paper, single-crystalline rutileTiO2 nanorod arrays were fabricated on the GaN based light emitting diodes (LEDs) with a TiO2 seed layer by an acid hydrothermal process. The morphologies and the crystallinity of the rutileTiO2 nanorod arrays on GaN wafer were characterized by scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction. The optical properties of surface-textured TiO2/GaN were measured and analyzed by photoluminescence. The influence and dependence of the TiO2 nanorod array with the different densities and diameters on the light output of the fabricated GaN wafers were investigated. The light extraction efficiency of GaN LEDs was enhanced by the single-crystalline rutileTiO2 nanorod array, which showed an eight-fold increase in photoluminescence intensity compared to the normal planar surface. The mechanisms for the enhanced light output of GaN LEDs by the single-crystalline rutileTiO2 nanorod arrays were discussed.

In this paper, a microwave-assisted synthesis method has been used to prepare highly luminescent GSH-capped Zn1−xCdxTe alloyed quantum dots, with pollutant-free sodium tellurite (Na2TeO3) as the Te source. The size and composition-dependent absorption and photoluminescence spectra of the as-prepared alloyed QDs can be tuned from 500 nm to 610 nm, and the photoluminescent quantum yield of our synthesized alloyed QDs can reach up to 90%. The in vitro cytotoxicity studies (MTT-assay) demonstrate that the cytotoxicity of the GSH-capped Zn1−xCdxTe alloyed QDs can be reduced to a small extent due to the incorporation of the Zn ions. Green emitting GSH-capped Zn1−xCdxTe alloyed QDs are successfully used for A549 cellular imaging on a laser scanning confocal microscopy. Our systematic investigation clearly shows that these high-performance Zn1−xCdxTe alloyed QDs are highly promising biological fluorescent labels in biological applications.