Luminescent Properties and Thermometry of CaWO4:Nd3+ in Near Infrared Region

2017 ◽  
Vol 893 ◽  
pp. 156-160
Author(s):  
Rong Xue Wang ◽  
Xiao Bing Luo
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Infrared Region ◽  
Excitation Spectra ◽  
Efficient Energy Transfer ◽  
Fluorescent Intensity ◽  
Sensor Device ◽  
The Matrix ◽  
Increasing Temperature

CaWO4: xNd3+ (x = 0.005, 0.008, 0.01, 0.015, 0.02, 0.025 0.03) powders have been synthesized by high-temperature solid state reaction. The results of the XRD indicate that Nd3+ ions have entered into the crystal lattice in all compounds successfully. The reflectance spectra show that the matrix has strong absorption. The emission spectra, excitation spectra and different lifetimes between CaWO4 and CaWO4: 0.5% Nd3+ indicate that efficient energy transfer occurs from WO42- cluster to Nd3+ ions. On the basis of the above work, the dependence of fluorescent spectra on temperature was studied. It turned out that, not only the excitation spectra appeared red shift with increasing temperature, but also the dependence of the near infrared fluorescent intensity on temperature is fitting with a linear function. It might be served as a promising phosphor for temperature sensor device.

Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing

2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Organic Additive ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Close Relationship ◽  
Dip Coating Technique

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.

scholarly journals Synthesis and Luminescent Properties of Eu3+/Tb3+ Rare Earth Ions Doped Li2SrSiO4 Phosphors

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaitao Yu ◽  
Lifang Wei ◽  
Jiaqi Shen
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Uv Visible

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

Photo and Electroluminescent Properties of a Porphyrin-Poly(p-Phenylene Vinylene) Derivative

1999 ◽  
Vol 598 ◽  
Author(s):  
J. Morgado ◽  
R. Iqbal ◽  
G. Yahioglu ◽  
L. R. Milgrom ◽  
S. C. Moratti ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Solid State ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Phenylene Vinylene ◽  
Efficient Energy Transfer ◽  
Light Emitting ◽  
Efficient Energy ◽  
Small Absorption ◽  
Pl Emission

ABSTRACTThe solid state luminescent properties of new statistical copolymers of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and a porphyrin-substituted phenylene vinylene are reported. The photoluminescence, PL, emission shows an efficient energy transfer to the porphyrin, in spite of the small absorption coefficient of the porphyrin in the wavelength range of the poly [2-methoxy-5-(2'- ethylhexyloxy)-1,4-phenylene vinylene], MEH-PPV, emission. At a porphyrin content of 0.25%, by weight, the emission is already dominated by the porphyrin. The PL efficiency of these copolymers is significantly reduced from the value of 13% for MEH-PPV down to 3% for the copolymer with 10.84% of porphyrin. Efficient energy transfer is also observed in the emission spectra of light-emitting diodes.

scholarly journals New Multicolor Tungstate-Molybdate Microphosphors as an Alternative to LED Components

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6608
Author(s):  
Justyna Czajka ◽  
Agata Szczeszak ◽  
Nina Kaczorowska ◽  
Stefan Lis
Keyword(s):  
Color Change ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Luminescence Spectroscopy ◽  
Solid State Method ◽  
Light Emitting ◽  
Tetragonal Crystal ◽  
Emission Color ◽  
The Matrix ◽  
Cie Chromaticity

Due to the ongoing need to create phosphors with the appropriate emission color for the production of light emitting diodes, we decided to synthesize a series of multicolour microphosphors with tunable visible emissions, depending on the composition of dopant ions. In this work, we investigated the structure, morphology, and luminescent properties of new molybdate–tungstate phosphors co-doped with Tb3+ and Eu3+ ions. The conventional high temperature solid state method was used to prepare a series of CaMoyW1−yO4:Eu3+x/Tb3+1−x materials. In order to obtain phosphors with the most promising luminescent properties, the experiment was planned by taking into account the different composition of the matrix and the concentration of the particular dopant ions (Eu3+x/Tb3+1−x, x = 0.001, 0.003, 0.005, 0.007, 0.009). As a result, luminescent materials were obtained with a pure tetragonal crystal structure, the space group of I41/a, confirmed by X-ray diffraction (XRD). The size and shape of the particles obtained from the materials were analyzed based on scanning electron microscopy images. Luminescence spectroscopy (excitation and emission spectra, decay lifetimes) was utilized to characterize the luminescence properties of the as-prepared phosphors. The color change of the emission from green-yellow to orange-red was confirmed using the 1931 Comission Internationale de l’Eclairage (CIE) chromaticity coordinates and color correlated temperature (CCT).

scholarly journals Defect Related Emission in Calcium Hydroxide: The Controversial Band at 780 cm−1

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 266 ◽  
Author(s):  
Francesca Assunta Pisu ◽  
Daniele Chiriu ◽  
Pier Carlo Ricci ◽  
Carlo Maria Carbonaro
Keyword(s):  
Cultural Heritage ◽  
Calcium Hydroxide ◽  
Raman Spectra ◽  
Near Infrared ◽  
Specific Treatment ◽  
Emission Spectra ◽  
Infrared Region ◽  
Carbonation Process ◽  
Composite Band ◽  
Post Synthesis

Calcium hydroxide, a crystal involved in the cycle of calcination and carbonation of calcium oxide, finds several applications from cultural heritage to the dentistry branch or to the construction industry. When excited at 1064 nm, Raman spectra of calcium hydroxide show a broad composite band peaked at about 780 cm−1, corresponding to 1170 nm. Since it is not observed with visible excitation, the origin of this band is debated, being assigned to some pre-existent luminescent impurities or some structural defect of the lime formed after the synthesis of the material. To shed light on the formation of this band, we synthetised the lime paste starting from pure calcite powders. The obtained fresh Ca(OH)2 samples did not show any band in the investigated range, irrespective of the laser excitation applied. A detailed analysis of the excitation and emission spectra in the near infrared region did not show the 1170 nm band, supporting the hypothesis of a post-synthesis origin. Thus, we carried out thermal treatments at different temperatures (90–500 °C) and under different environments (in air or under nitrogen flux) on synthesised fresh Ca(OH)2 powders. We also investigated the time evolution of the samples, monitoring the Raman spectra over 90 days after a specific treatment. The collected data support the hypothesis of a defect-related luminescence centre, whose formation depends on the temperature and environment of the treatment, which appears as a preferential site for the carbonation process of the calcium hydroxide. These results can be useful in the field of Cultural Heritage for dating purposes, and to determine the conservation state of Ca(OH)2 containing relics to prevent the possible activation of degradation processes.

Hydrothermal Synthesis and Size-Enhanced Chromaticity of Sr2ZnSi2O7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1449-1453 ◽  
Author(s):  
Junxi Wan ◽  
Youwei Yao ◽  
Guoyi Tang ◽  
Yitai Qian
Keyword(s):  
Bulk Material ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Blue Shift ◽  
Average Diameter ◽  
Hydrothermal Route ◽  
Excitation Spectra ◽  
Red Phosphor ◽  
Red Phosphors ◽  
20 Nm

Red phosphor Sr2ZnSi2O7:Eu3+ nanoparticles with an average diameter of 20 nm were successfully synthesized via a low-temperature hydrothermal route in order to understand the underlying relationship between size and luminescent properties. The nanometer-sized particles result in a distinct improvement in chromaticity and a high quenching concentration. According to emission spectra, the relative intensity of the 5D0 → 7F2 to 5D0 → 7F1 transitions in nanometer-sized phosphors is higher than that of the corresponding bulk material. The better chromaticity results from the more distorted lattices and relatively lower crystal symmetry around the Eu3+ ions, which is ascribed to the large surface area due to the nanometer size of the phosphor. Moreover, the nanometer-sized Sr2ZnSi2O7:Eu3+ red phosphor exhibits a shorter fluorescent lifetime and a blue-shift in excitation spectra compared to that of its bulk counterpart. These results indicate that size-induced enhancement of luminescent properties is an efficient way to obtain red phosphors with better chromaticity.

Luminescent Properties of La3PO7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1410-1413 ◽  
Author(s):  
Shaozhe Lü ◽  
Jishen Zhang
Keyword(s):  
Charge Transfer Band ◽  
Emission Spectra ◽  
Local Environment ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Time Resolved ◽  
Transmission Electron ◽  
Light Excitation ◽  
Average Size

La3PO7:Eu3+ samples were prepared by combustion and annealing and characterized by X-ray diffraction and transmission electron microscopy. It was found that the average size of the particles is about 80 nm. The red emission from the 5D0 → 7F2 transition of the Eu3+ ions under ultraviolet light excitation is much stronger than the orange emission from the 5D0 → 7F1 transition. The emission spectra, charge transfer band, laser selective excitation spectra, and time-resolved spectra indicate that symmetry of the local environment of Eu3+ lacks an inversion center and Eu3+ ions occupy at least two types of sites in the La3PO7 crystal. The superior color chromaticity compared to other phosphates and borates doped with Eu3+ means La3PO7:Eu3+ may have potential as a luminescent material.

The formation and detection of some low-lying excited electronic states of BrCl and other halogens

1967 ◽  
Vol 298 (1455) ◽  
pp. 424-452 ◽  
Keyword(s):  
Ground State ◽  
Near Infrared ◽  
Transfer Reaction ◽  
Potential Energy Curve ◽  
Emission Spectra ◽  
Infrared Region ◽  
Band Head ◽  
Energy Curve ◽  
Chlorine Atoms ◽  
Formula Type

Forty-nine bands arising from have been detected in the emission spectrum of from two sources: (i) the reaction of Br or Br 2 with ClO 2 , in which is populated in the transfer reaction, 3 and (ii) the radiative combination of bromine and chlorine atoms, 5 The populations of the higher levels of formed in reaction (3) are less than in reaction (5). In reaction (3), is evidently formed via a triangular transition state similar to that postulated previously; the rate constant, k 3 , was found to be The combination of ground state iodine , and chlorine atoms was also found to be chemiluminescent in the red and near infrared region, and fifty-seven bands of the system , with , have been recorded. The radiative combination of ground-state chlorine atoms has been reinvestigated, and transitions of from v ' ≼ 14 have been detected. Combining band head analyses of these emission spectra with previous data, the following constants (in cm -1 ) are reported: The reasons for the predominant radiation, during atom combination processes, from type states for Cl 2 and BrCl, and from the 3 II 1 state for ICl, are discussed in relation to Brown & Gibson’s (1932) finding of a maximum in the potential energy curve of leading to and as dissociation products.

Characterization of Near-Infrared Nonmetal Atomic Emission from an Atmospheric Helium Microwave-Induced Plasma Using a Fourier Transform Spectrophotometer

1986 ◽  
Vol 40 (6) ◽  
pp. 759-766 ◽  
Author(s):  
Joseph Hubert ◽  
Huu Van Tra ◽  
Khanh Chi Tran ◽  
Frederick L. Baudais
Keyword(s):  
Fourier Transform ◽  
Near Infrared ◽  
Microwave Plasma ◽  
Emission Spectra ◽  
Plasma Source ◽  
Atomic Emission ◽  
Infrared Region ◽  
Emission Lines ◽  
Helium Plasma ◽  
Microwave Induced Plasma

A new approach for using Fourier transform spectroscopy (FTS) for the detection of atomic emission from an atmospheric helium plasma has been developed and the results obtained are described. Among the different types of plasma source available, the atmospheric pressure microwave helium plasma appears to be an efficient excitation source for the determination of nonmetal species. The more complete microwave plasma emission spectra of Cl, Br, I, S, O, P, C, N, and He in the near-infrared region were obtained and their corrected relative emission intensities are reported. This makes qualitative identification simple, and aids in the quantitative analysis of atomic species. The accuracy of the emission wavelengths obtained with the Fourier transform spectrophotometer was excellent and the resolution provided by the FTS allowed certain adjacent emission lines to be resolved. These atomic emission lines were found to be adequate for analytical applications.

Sign in / Sign up

Export Citation Format

Share Document