We analyze long-slit spectral observations of 39 Wolf-Rayet (WR) galaxies with heavy element mass fraction ranging over 2 orders of magnitude, from Z⊙/50 to 2Z⊙. Nearly all galaxies in our sample show broad WR emission in the blue region of the spectrum (the blue bump) consisting of an unresolved blend of N III λ4640, C III λ4650, C IV λ4658 and He II λ4686 emission lines. Broad C IV λ5808 emis...

Photoluminescence (PL) emission and excitation (EPL) spectra of un-doped and indium (1%) doped 1D zinc oxide nanostructures are studied at different temperatures. The nanostructures reveal a blue emission band attributed to localized donor states. Indium doping enhances the blue emission. While at low temperatures (< 50 K) PL spectra are dominated by the emission attributed to the recombination...

Highly efficient light-emitting diodes (LEDs) emitting ultraviolet (UV), blue, green, amber and red light have been obtained through the use of InGaN active layers instead of GaN active layers. Red LEDs with an emission wavelength of 675 nm, whose emission energy was almost equal to the band-gap energy of InN, were fabricated. The dependence of the emission wavelength of the red LED on the curr...

A facile method of preparing stable blue-emitting silicon nanoparticles that are dispersible in common organic solvents is presented. Oxidation of yellow-emitting silicon nanoparticles with an organic monolayer grafted to their surface, using either UV irradiation in solution or heating in air, converted them to blue-emitting particles. The evolution of the PL spectrum and infrared absorption s...

22GHz water vapor ‘kilomaser’ emission is reported from the central region of the Whirlpool galaxy M51 (NGC5194). The red-shifted spectral features (VLSR∼ 560 km s ), flaring during most of the year 2000, originate from a spatially unresolved maser spot of size < ∼ 30mas (< ∼ 1.5 pc), displaced by < ∼ 250mas from the nucleus. The data provide the first direct evidence for the association of an ...

Blue-emitting heteroleptic aluminum(III) bis(2-methyl-8-quinolinolate)phenolate complexes were synthesized. A tunable, blue-to-green emission is achieved by attaching electron-withdrawing modulators to the emisssive quinaldinate ligand. The electronic nature of modulator substituents attached to the position of the highest HOMO (highest occupied molecular orbital) density is used to modulate li...

In this study, water-soluble silicon quantum dots have quasi-blue emission at 390 nm by being capped with 1-vinylimidazole in resese micelles. As-obtained silicon quantum dots have a diameter of 2~5 nm and high crystallinity. The quasi-blue emission of the silicon quantum dots is likely attributed to the polarity of the capping ligands. Moreover, the silicon quantum dots are water-soluble and h...

We report on the synthesis of gallium oxide nanowires by pulsed laser deposition using a gold catalyst. In the vapor-liquid-solid process, gold thickness was the crucial parameter for deciding the morphology of nanowires. In the case of 1 nm thick gold, homogeneous nanowire growth was confirmed at temperatures of 700 ̊C to 850 ̊C. Transmission electron microscopy and selected area electron diffra...

Simple mononuclear Cu(I)-halide complexes, [CuX(PPh3)2(4-Mepy)] (X = Cl(-), Br(-), I(-); PPh3 = triphenylphosphine; 4-Mepy = 4-methylpyridine), were prepared. They exhibit blue light emission, with extremely high photoluminescence quantum yields approaching 100% in the crystals. Emission lifetime analyses and density functional theory calculations revealed that the bright blue light emission at...

Ultra-thin quantum wells of CdTe and CdSe and fractional monolayer quantum dots of CdSe present very strong excitonic emission covering the red-blue spectral range. They are grown by atomic layer epitaxy and the thickness fluctuations can be completely avoided in many cases by choosing the appropriate substrate temperature. These systems appear as promising candidates for the elaboration of red...