Here in this contribution, blue and red luminescent 1-dodecanethiol (DT) terminated gold nanoclusters (AuNC) were prepared by a simple two-step synthesis route where the first step involved the surfactant-free synthesis of bare AuNC in N,N′-dimethylformamide (DMF) and the second step is the termination of the as-prepared bare AuNC by 1-dodecanethiol. The blue and red luminescent DT-terminated AuNC were isolated by a solvent-induced precipitation followed by an ultra-centrifugation technique. Both the bare AuNC and the blue and red luminescent DT-terminated AuNC exhibit stable photoluminescence and good solubility in various solvents. The photo-physical, electronic, structural, and morphological properties of the bare AuNC and the blue and red luminescent DT-terminated AuNC were examined by performing UV-Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy (XPS), femtosecond transient absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR-ATR), and high-resolution transmission electron microscopy (HRTEM) experiments.

In this paper, we reported a very simple and environmentally friendly procedure for the synthesis of bright luminescent and nearly monodisperse Ag nanoclusters stabilized by a poly(N-vinylpyrrolidone) homopolymer. In this synthesis route acetonitrile or N,N-dimethylformamide (DMF) acts as both solvent and a reducing agent at their respective reflux temperatures. The as-prepared Ag clusters were found to be highly stable in various solvents as well as show nearly no changes in their emission intensity in solutions with different pH values and ionic strengths. Remarkably, the acetonitrile method predominantly produces blue emitting Ag clusters with a photoluminescence (PL) emission maximum at 424 nm (quantum yield 3.5%), whereas mainly blue-green emitting Ag clusters with the PL emission maximum at 450 nm (quantum yield 2.7%) were formed using the DMF method. The photo-physical, electronic, structural and morphological properties of the Ag clusters were investigated by performing UV/Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and transmission electron microscopy experiments.

Here in this paper, we reported of a facile photo-induced one-step method for synthesizing highly luminescent Au(I)–thiolate complexes (size ~2–3 nm) and thiolated Au nanocluster (AuNC, size ~1.6 nm). The hydrophilic thiol being 3-mercaptopropanoic acid (3-MPA) was used as stabilizing agent. The as-prepared Au(I)–thiolate complexes exhibit bright red photoluminescence (PL) and were used as an efficient sensor for the selective detection of Cu2+ ions. We also observed the formation of thiol-stabilized Au nanoparticles through continuous electron beam irradiation of Au(I)–thiolated complexes. The Au(I)–thiolate complexes show a PL lifetime on the μs time scale, whereas the PL lifetime of the thiolated AuNC is on the ns time scales. The photo-physical, electronic, structural and morphological properties of the thiolated AuNC and Au(I)–thiolate complexes were examined upon performing UV–Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy and transmission electron microscopy experiments.

Superparamagnetic iron oxide nanoparticles (SPIONs) with a mixed phase composition (γ-Fe2O3)1–x(Fe3O4)x and sizes between 9 and 20 nm were synthesized via coprecipitation and were either left uncoated or subsequently surface-stabilized with citrate or malate anions. The sizes, morphology, surface chemistry, and magnetic properties of the nanoparticles were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and superconducting quantum interference device measurements, respectively. Cellular uptake and intracellular distribution in normal tissue and tumor cells were verified by TEM images. X-ray-induced changes of the oxidation state and site geometries of surface iron ions of uncoated and citrate-coated SPIONs were explored by collecting Fe K-edge X-ray absorption spectroscopy data. The potential applicability of citrate- and malate-coated SPIONs as an X-ray enhancer for radiation cancer therapy was substantiated by their drastic enhancement of the concentration of reactive oxygen species (ROS) in X-ray irradiated tumor cells.

The adsorption behavior and electronic interactions of bovine serum albumin (BSA) with ZnO nanorod surfaces were investigated using high-resolution transmission electron microscopy as well as stationary and time-resolved optical spectroscopy techniques. Transmission electron microscopy shows that ZnO nanorod surfaces are surrounded by a homogeneous amorphous BSA film with thicknesses between ∼2.5 and 5.0 nm. The electronic structure and adsorption geometry of BSA were examined using high-angle annular dark field scanning transmission electron microscopy combined with electron energy loss spectroscopy. The adsorption process was observed to result into an unfolded conformation of BSA becoming predominantly bound in the side-on orientation at the ZnO surface. This adsorption mode of the BSA molecules allows for a strong interaction with surface states of the ZnO nanorods. This is obvious from its efficient quenching of the defect-center photoluminescence of ZnO. Complementary information of electronic interactions across the ZnO nanorod interface was obtained from femtosecond transient absorption spectroscopy experiments. The rise dynamics of the measured transients revealed altered hole trapping dynamics and, thus, indicated to heterogeneous charge transfer as emerging from adsorbed BSA molecules to defect centers of the ZnO interface.

Here in this contribution, blue and red luminescent 1-dodecanethiol (DT) terminated gold nanoclusters (AuNC) were prepared by a simple two-step synthesis route where the first step involved the surfactant-free synthesis of bare AuNC in N,N′-dimethylformamide (DMF) and the second step is the termination of the as-prepared bare AuNC by 1-dodecanethiol. The blue and red luminescent DT-terminated AuNC were isolated by a solvent-induced precipitation followed by an ultra-centrifugation technique. Both the bare AuNC and the blue and red luminescent DT-terminated AuNC exhibit stable photoluminescence and good solubility in various solvents. The photo-physical, electronic, structural, and morphological properties of the bare AuNC and the blue and red luminescent DT-terminated AuNC were examined by performing UV-Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy (XPS), femtosecond transient absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR-ATR), and high-resolution transmission electron microscopy (HRTEM) experiments.

In this paper, we reported a very simple and environmentally friendly procedure for the synthesis of bright luminescent and nearly monodisperse Ag nanoclusters stabilized by a poly(N-vinylpyrrolidone) homopolymer. In this synthesis route acetonitrile or N,N-dimethylformamide (DMF) acts as both solvent and a reducing agent at their respective reflux temperatures. The as-prepared Ag clusters were found to be highly stable in various solvents as well as show nearly no changes in their emission intensity in solutions with different pH values and ionic strengths. Remarkably, the acetonitrile method predominantly produces blue emitting Ag clusters with a photoluminescence (PL) emission maximum at 424 nm (quantum yield 3.5%), whereas mainly blue-green emitting Ag clusters with the PL emission maximum at 450 nm (quantum yield 2.7%) were formed using the DMF method. The photo-physical, electronic, structural and morphological properties of the Ag clusters were investigated by performing UV/Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and transmission electron microscopy experiments.