Search results for " Luminescence"
showing 10 items of 159 documents
Active Media for Optical Data Processing
2002
Peculiarities of colour centre production and their recombination in photostimulated processes in doped alkali halide systems were examined in connection with their practical use as active photostimulable media in miniaturised optoelectronic and photonic devices. The specific interaction of unrelaxed H-centres and electrons with the dopants in different valence and electronic states open a way for widening the scope of multifunctional (logical and mathematical) optical data processing, including the optical chips.
Photostimulated luminescence properties of neutron image plates
2016
Abstract The luminescence properties of two commercial neutron-sensitive image-plates based on Gd 2 O 3 -doped BaFBr:Eu 2 + storage phosphors are examined. These are white Fuji plates and blue Fuji plates (BAS-ND) with Gd 2 O 3 content by weight of 34% and 50%, respectively. Both plates show two maxima in the photostimulation spectrum near 500 nm and 600 nm, with the ratio of the peak responses ( I 600 nm / I 500 nm ) 1.39 and 0.53 for the white and blue plates respectively. The optimum wavelengths for photostimulation for the two phosphors are therefore different. The response of the blue plate is only 25% that of the white plate, if each is stimulated at its optimum wavelength.
Time resolved luminescence spectroscopy of CsPbBr3 single crystal
2020
Abstract The work reports the results of spectroscopic and luminescence-kinetic studies of CsPbBr3 single crystal over 14–300 K temperature range. It is shown that at low temperatures the luminescence spectrum contains three narrow bands at 534, 537, and 541.5 nm exhibiting a fast decay and a broad emission band at ca. 560 nm with long decay. The evolution of the luminescence bands and their temporal characteristics with temperature are discussed from the viewpoint of possible emission mechanisms. The origin of the luminescence bands is discussed in relation with the observed features of their temporal characteristics. The mechanism of luminescence quenching for different emission band is s…
Recombination luminescence of X-ray induced paramagnetic defects in BaY2F8
2020
This research is funded by the Latvian Council of Science , project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1–0335 . The crystal growth research was funded by the CNPq (Brazil), project NO 421581/2016–6 .
Luminescence of phosphorus doped silica glass
2017
This work is supported by Material Science program IMIS2 of Latvia.
UV and X-ray excited red persistent luminescence in Mn2+ doped MgGeO3 material synthesized in air and reducing atmosphere
2021
Abstract Materials with long persistent luminescence (PersL) have caused widespread interest among scientists and industry for decades. Currently, there is widely available information on the long persistent luminescence materials with emission in the blue and green spectral range, while the number of publications on the afterglow in the red and near-infrared spectral range is considerably lower. In the course of this work MgGeO3 material doped with 0.1 mol% Mn2+ was produced using solid-state reaction synthesis in ambient and reducing atmospheres. The material exhibits a broad luminescence band with a peak around 680 nm, excited by either X-rays or UV. After cessation of irradiation, the a…
Enhancement of persistent luminescence in Ca2SnO4: Sm3+
2021
Abstract Reddish-orange persistent luminescent Ca2SnO4: 0.1% Sm3+ co-doped with 0–10% Gd3+ was prepared using solid state synthesis. The phase formation and morphology was analyzed using X-ray diffraction and scanning electron microscopy. Incorporation of Sm3+ and Gd3+ in Ca2SnO4 lattice was investigated using site-selective spectroscopy and electron paramagnetic resonance. In all samples reddish-orange persistent luminescence and photochromic effect was observed after excitation with UV as well as X-rays. The thermostimulated luminescence curves indicated that the introduction of Gd3+ increases the number of shallow traps of charges which enhance the intensity of persistent luminescence. I…
Luminescent silicon nanocrystals produced by near-infrared nanosecond pulsed laser ablation in water
2014
Abstract We report the investigation of luminescent nanoparticles produced by ns pulsed Nd:YAG laser ablation of silicon in water. Combined characterization by AFM and IR techniques proves that these nanoparticles have a mean size of ∼3 nm and a core–shell structure consisting of a Si-nanocrystal surrounded by an oxide layer. Time resolved luminescence spectra evidence visible and UV emissions; a band around 1.9 eV originates from Si-nanocrystals, while two bands centered at 2.7 eV and 4.4 eV are associated with oxygen deficient centers in the SiO 2 shell.
Visible luminescence peculiar to sintered silica nanoparticles: Spectral and decay properties
2015
We report that the sintering at 1000 degrees C of silica nanoparticles (an average diameter of 14 nm) produces a transparent sample that exhibits a bright visible emission under UV excitation. The use of time resolved luminescence spectroscopy and a tunable laser source allows us to single out three contributions centered at 1.96 eV, 2.41 eV and 3.43 eV. The excitation spectra of these emissions evidence bell shaped bands consistent with transitions between localized defects' states. For each emission we study the intensity and the lifetime in the temperature range from 300 K down to 10 K, thus evidencing the competition between radiative and non-radiative processes in the optical cycle of …
Optical studies of Y3(Al,Ga)5O12:Ce3+,Cr3+,Nd3+ nano-phosphors obtained by the Pechini method
2019
The Y-3(Al,Ga)(5)O-12:Ce3+,Cr3+,Nd3+ (YAGG) nano-phosphors with homogeneous particle-size distribution, low aggregation and average crystalline size of about 65 nm were obtained using a modified Pechini method. Only slight aggregation of the crystallites occurs after post-annealing at 1100 degrees C. The intense Ce3+ bands in the excitation spectra of the Ce3+,Cr3+,Nd3+ co-doped materials monitoring the Cr3+ emission at 690 nm indicate energy transfer from Ce(3+ )to Cr3+. Weak Nd3+ lines are observed, as well. In addition, the emission of Nd3+ at 1060 nm with excitation of Ce3+ and Cr3+ confirms the Ce3+/Cr3+ to Nd3+ energy transfer. The short average luminescence decay times for the Ce3+ e…