The energy transfer in 3He and 4He clusters electronically excited by monochromatic synchrotron radiation is investigated by luminescence spectroscopy. Depending on the cluster size and the isotopic constitution, either sharp, broadened, or shifted emission bands of single He molecules are observed. The spectral features show that He molecules emit light either within a bubble inside the cluste...

in this research work, we report a simple method called reflux condensation method for synthesizing co3o4 nanoparticles using cheap chemicals such as, cobalt acetate (precursor salt), sodium monododecyl sulphate - sds (surfactant) and n, n - dimethylformamide - dmf (solvent). the prepared materials were heat treated at 200, 400, 600 and 800 oc for each 2 h to get phase pure product. the calcine...

Poly(amidoamine) dendrimers are typical luminescent polymers containing unconventional chromophores. A series of novel siloxane-poly(amidoamine) (Si-PAMAM) dendrimers were synthesized and investigated in this study. Their structures and properties were determined by NMR, XPS, LC/MS, and fluorescence spectroscopy. The introduction of Si-O-Si units in Si-PAMAM changed the photophysical properties...

This work presents a simple method to generate ordered chromophore/dispersant nanoarrays through a pore-filling process for a nanoporous polymer template to enhance chromophore luminescence. Fluorescence results combining with the morphological evolution examined by scanning probe microscopy reveal that the enhanced luminescence intensity reaches the maximum intensity as the nanopores of the te...

The binding of asymmetrical and optically pure tridentate ligands (L = 1(S) and 1(R)) containing one carboxylic group and 2-naphthyl as an antenna to lanthanide ions (M = La(iii) and Eu(iii)) was studied in CH3CN, showing the successive formation of M:L, M:L2 and M:L3 stoichiometric species in solution. The europium complexes EuL3 were also synthesised, structurally characterised and their phot...

Using photo-luminescence, infrared spectroscopy, and electron spin resonance technique, the silicon dioxide films with embedded silicon nanocrystals (nc-Si/SiO2 structures) have been investigated after γ-irradiation with the dose 2 × 107 rad and subsequent annealing at 450 °C in hydrogen ambient. For the first time, it was shown that such a radiation-thermal treatment results in significant inc...

Bismuth doped yttrium niobate (YNbO4:Bi) is a potential blue phosphor for field emission displays application. It is observed after introducing Bi ions that cathodoluminescence efficiency of YNbO4:Bi becomes lower than that of YNbO4 . From the calculations of critical distance (RC) of energy transfer and Huang–Rhys parameter (SHR) of YNbO4:Bi, it is found that the energy transfer by a dipolar-t...

Cathodoluminescence (CL) imaging and spectroscopy have been used to characterize fully strained SiGe quantum wells grown on Si. At T-5 K, the CL spectra contain only band edge luminescence features. Monochromatic imaging with the no-phonon line attributed to the bound excitons in the quantum well, has shown that the distribution of the luminescence from the wells is not uniform. The thinnest we...

Direct excitation at 1064 nm and detection of singlet molecular oxygen at 1270 nm is made possible by the availability of powerful YAG-lasers and sensitive NIR photomultipliers. Singlet oxygen was generated in condensed phase at 77 K by direct excitation at 1064 nm (without the use of sensitizers). Several luminescing species were observed by time resolved luminescence spectroscopy and luminesc...

The preparation of two-component polymer composite nanoparticles encapsulating both Si quantum dots (SiQDs) and Au nanoparticles (AuNPs) by a single step miniemulsion polymerization of divinylbenzene is described. This simple and robust method affords well-defined polymer composite nanoparticles with mean diameters in a range of 100–200 nm and with narrow polydispersity indices as determined by...