scholarly journals Role of the triplet state in the green emission peak of polyfluorene films: A time evolution study

2010 ◽  
Vol 132 (4) ◽  
pp. 044104 ◽  
Author(s):  
S. Mukhopadhyay ◽  
S. Ramasesha ◽  
S. Guha
Keyword(s):  
Triplet State ◽  
Time Evolution ◽  
Green Emission ◽  
Emission Peak ◽  
Green Emission Peak ◽  
Evolution Study

Photoluminescent Properties of Al Doped ZnO by Microwave Induced Combustion Method

2012 ◽  
Vol 554-556 ◽  
pp. 644-648
Author(s):  
Yuan Cao ◽  
Ya Tao Wang ◽  
Ping Li
Keyword(s):  
Deep Level ◽  
Green Emission ◽  
Combustion Method ◽  
Zinc Nitrate ◽  
Emission Peak ◽  
Aluminum Nitrate ◽  
Molar Ratio ◽  
Green Emission Peak ◽  
Zno Nanomaterials ◽  
Doped Zno

Al-doped ZnO nanomaterials were synthesized by microwave-induced combustion method using urea as main fuel, aluminum nitrate provide doping ions and zinc nitrate as oxidant. The effects of microwave power, amount of urea and ratio aluminum nitrate to zinc nitrate on the properties of synthesized sampler were investigated .X-ray, diffraction(XRD), scanning electron microscope(SEM), and photoluminescence(PL) were used to characterize the properties of the sample respectively. The experimental results show that ZnO nanomaterials with cubic ZnO crystal phase of best optical property are obtained at 340W when molar ratio of the zinc nitrate to aluminum nitrate is 40% and fuel just completely reaction. The average primary granularity of the synopsized sample is about 56rnm estimated according to Scherrer Equation. PL test results indicate that the Ultraviolet(UV) emission peak in 360nm can be attributed to the recombination of free excitations through an excitation-excitation collision process, and the green emission peak in 470nm is commonly referred to a deep-level or trap-state.

Non-Linear Optical Properties of Zinc Oxide Nanowires

2008 ◽  
Vol 8 (3) ◽  
pp. 1150-1154
Author(s):  
C. F. Tang ◽  
H. Deng ◽  
B. Tang ◽  
H. Cheng ◽  
J. C. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Second Harmonic ◽  
Rabi Oscillation ◽  
Green Emission ◽  
Pump Intensity ◽  
Zno Nanowires ◽  
Emission Peak ◽  
Photon Absorption ◽  
Optical Process ◽  
Green Emission Peak

High quality zinc oxide (ZnO) nanowires were grown on n-type Si (100) using vapor-liquid-solid process. We obtained the photoluminescence spectra of ZnO nanowires based on nonlinear optical process using an ultrashort wavelength femtosecond laser as a pumping source. The spectra shows the second harmonic generation phenomenon, as well as the exciton–exciton collision peak at 388 nm and the green emission peak at 515 nm caused by oxygen vacancy. A laser emission peak near 392 nm was observed when pump intensity surpassed 52 mJ/cm2 and a sharp peak about 0.5 nm wide emerged when the energy intensity reached 700 mJ/cm2. We attribute this excitation process to a two-photon absorption process enhanced by Rabi oscillation.

Structural and Photoluminescence Characteristics of Cu Doped CdS Nanoparticles

2018 ◽  
Vol 24 (8) ◽  
pp. 5657-5660
Author(s):  
K Raviteja ◽  
N Sreelekha ◽  
D. Amaranatha Reddy ◽  
R. P Vijayalakshmi ◽  
K Subramanyam
Keyword(s):  
Green Emission ◽  
Host Lattice ◽  
Emission Peak ◽  
Cds Nanoparticles ◽  
Stoichiometric Ratio ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Green Emission Peak ◽  
Diffraction Patterns

EDTA surfactant assisted bare and Cu doped CdS nanoparticles were prepared by simple chemical coprecipitation method. As the prepared samples were characterized by energy dispersive analysis of X-rays (EDAX), X-ray diffraction patterns (XRD), transmission electron microscopy (TEM), Raman spectroscopy and photoluminescence spectroscopy (PL). Existence of Cu in host lattice with near stoichiometric ratio was corroborated by EDAX spectra. X-ray diffraction patterns revealed that cubic structure as that of CdS host lattice. TEM images suggested that spherical nature of nanoparticles with a size ranging from 4–6 nm. Room temperature photoluminescence (PL) spectra revealed that pristine host lattice nanoparticles demonstrate a strong green emission peak located at 525 nm as well as weak red emission shoulder situated at 598 nm. Auxiliary in Cu doped CdS samples, the luminescence intensity was gradually reduced as well as the green emission peak was shifted to red region (660 nm). With increase of Cu content in host matrix a red shift is found in the PL emission peak.

Photoluminescence Properties of (Ba1-(x+y)SrxEuy)2Si6O12N2 Phosphors for White LED Applications

2015 ◽  
Vol 36 ◽  
pp. 1-7 ◽  
Author(s):  
Narendra G. Sarda ◽  
Hiroshi Fujigaki ◽  
Yuma Ogita ◽  
Andrew Chan ◽  
Kei-Ichiro Murai ◽  
...  
Keyword(s):  
Green Emission ◽  
Solid State Reaction Method ◽  
Emission Peak ◽  
White Led ◽  
Photoluminescence Properties ◽  
Lattice Volume ◽  
Green Emission Peak ◽  
Potential Alternative ◽  
Light Excitation ◽  
The Eu

(Ba1-(x+y)SrxEuy)2Si6O12N2 oxynitride phosphors were successfully synthesized by the solid-state reaction method at 1200°C under a H2(5%) + N2(95%) atmosphere. The Sr2+ content (x) was varied in the range 0-0.6 and the Eu2+ content varied in the range 0.05-0.25, with the Si/(Ba+Sr+Eu) ratio fixed at 3. Results showed that the emission characteristics of (Ba1-(x+y)SrxEuy)2Si6O12N2 phosphors under UV or blue-light excitation was strongly dependent on the chemical composition. The phosphor (Ba0.95Eu0.05) Si6O12N2 showed an intense green emission peak at 520 nm, whilst the phosphor (Ba0.45Sr0.5Eu0.05)Si6O12N2 had a weaker emission maximum at 548 nm. Ba2+ substitution with Sr2+ decreased the lattice volume of the (Ba1-(x+y)SrxEuy)2Si6O12N2 phosphors and was responsible for the red-shift in the emission peak. Optimization of the Eu2+ concentration at a fixed Sr2+ content of 0.2 identified the phosphor (Ba0.65Sr0.2Eu0.15)2Si6O12N2 as a potential alternative to YAG:Ce yellow phosphors for white LED applications.

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