Highly intense room-temperature photoluminescence in V2O5 nanospheres.

Room-temperature photoluminescence (PL) in V2O5 nanospheres with zero-like dimensional structure was investigated. A large number of V4+ oxidation states in the nanospheres were observed by X-ray photoelectron spectroscopy (XPS) measurements. The nanospheres revealed high PL intensity compared with previous studies. In particular, they showed intense ultraviolet (UV) PL near a wavelength of 396 nm (3.13 eV). The intense UV PL was attributed to the enhanced transition probability due to the large number of V4+ (3d1) oxidation states. The PL properties showed strong dependencies on the oxidation states and their distribution.

Electron beam-formed ferromagnetic defects on MoS2 surface along 1 T phase transition.

1 T phase incorporation into 2H-MoS2 via an optimal electron irradiation leads to induce a weak ferromagnetic state at room temperature, together with the improved transport property. In addition to the 1T-like defects, the electron irradiation on the cleaved MoS2 surface forms the concentric circle-type defects that are caused by the 2 H/1 T phase transition and the vacancies of the nearby S atoms of the Mo atoms. The electron irradiation-reduced bandgap is promising in vanishing the Schottky barrier to attaining spintronics device. The simple method to control and improve the magnetic and electrical properties on the MoS2 surface provides suitable ways for the low-dimensional device applications.

Viscosity-dependent diffusion of fluorescent particles using fluorescence correlation spectroscopy.

Fluorescent particles show the variety characteristics by the interaction with other particles and solvent. In order to investigate the relationship between the dynamic properties of fluorescent particles and solvent viscosity, particle diffusion in various solvents was evaluated using a fluorescence correlation spectroscopy. Upon analyzing the correlation functions of AF-647, Q-dot, and beads with different viscosity values, the diffusion time of all particles was observed to increase with increasing solvent viscosity, and the ratio of diffusion time to solvent viscosity, τ D /η, showed a linear dependence on particle size. The particle diffusion coefficients calculated from the diffusion time decreased with increasing solvent viscosity. Further, the hydrodynamic radii of AF-647, Q-dot, and beads were 0.98 ± 0.1 nm, 64.8 ± 3.23 nm, and 89.8 ± 4.91 nm, respectively, revealing a linear dependence on τ D /η, which suggests that the hydrodynamic radius of a particle strongly depends on both the physical size of the particle and solvent viscosity.