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Photoluminescence Behavior (photoluminescence + behavior)
Selected AbstractsPlasma Nanoparticle Synthesis: Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible Spectrum (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Mater. The cover picture shows a view into the plasma zone of a microwave plasma reactor, which is used to synthesize macroscopic quantities of single crystalline silicon nanoparticles with a very high production rate. These nanoparticles exhibit bright luminescence across the visible spectrum. On page 696, the authors report that the emission of such silicon nanoparticles can be tuned by changing their size and surface chemistry. [source] Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible SpectrumADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Anoop Gupta Abstract Aiming for a more practical route to highly stable visible photoluminescence (PL) from silicon, a novel approach to produce luminescent silicon nanoparticles (Si-NPs) is developed. Single crystalline Si-NPs are synthesized by pyrolysis of silane (SiH4) in a microwave plasma reactor at very high production rates (0.1,10,g,h,1). The emission wavelength of the Si-NPs is controlled by etching them in a mixture of hydrofluoric acid and nitric acid. Emission across the entire visible spectrum is obtained by varying the etching time. It is observed that the air oxidation of the etched Si-NPs profoundly affects their optical properties, and causes their emission to blue-shift and diminish in intensity with time. Modification of the silicon surface by UV-induced hydrosilylation also causes a shift in the spectrum. The nature of the shift (red/blue) is dependent on the emission wavelength of the etched Si-NPs. In addition, the amount of shift depends on the type of organic ligand on the silicon surface and the UV exposure time. The surface modification of Si-NPs with different alkenes results in highly stable PL and allows their dispersion in a variety of organic solvents. This method of producing macroscopic quantities of Si-NPs with very high PL stability opens new avenues to applications of silicon quantum dots in optoelectronic and biological fields, and paves the way towards their commercialization. [source] Synthesis, Electrochemical and Photophysical Properties, and Electroluminescent Performance of the Octa- and Deca(aryl)[60]fullerene DerivativesADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Yutaka Matsuo Abstract Three multifunctionalized organo[60]fullerene derivatives, C60Ph5(C6H4 - tBu-4)5Me2 (cyclophenacene, 1), C60Ph5(C6H4 - tBu-4)5Me2 (fused corannulene, 2), and C60Ph5(C6H4 - tBu-4)3Me2 (phenylene-bridged fused corannulene, 3) are synthesized by the reaction of C60Ph5Me with 4- tert -butylphenylcopper reagent in the presence of pyridine, followed by treatment with MeI. Compounds 1,3 undergo reduction in the range from ,1.8 to ,2.5,V versus Fc/Fc+ and exhibit photoluminescence behavior with fluorescent quantum yields of 18.5%, 2.5%, and 3.2% with fluorescent lifetimes of 67, 1.1, and 27,ns (1,3, respectively). Organic electroluminescent diode devices using 1,3 are fabricated with ,-conjugated polymers and show external electroluminescent efficiencies of 0.04%, 0.07%, and 0.03% emitting yellow, green, and red light, respectively. The device containing all three compounds emits white light. This result indicates that the bulky addends in 1,3 can effectively isolate the ,-conjugated systems of the molecules in the solid state and retard the intermolecular excited-state quenching process. [source] Photoluminescence of High-Aspect-Ratio PbTiO3 Nanotube ArraysJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Yang Yang High-aspect-ratio PbTiO3 nanotube arrays have been synthesized by the hydrothermal method. X-ray diffraction result shows that PbTiO3 nanotube arrays have a tetragonal perovskite structure without any other impurity. The photoluminescence property of PbTiO3 nanotube arrays studied at room temperature reveals a strong green emission band peaking at 550 nm (2.25 eV). Both Raman spectroscopy and X-ray photoelectron spectroscopy demonstrate the existence of local defects in PbTiO3 nanotube arrays, which act as emission source and result in the photoluminescence behavior of PbTiO3 nanotube arrays. [source] | ||||||||||