scholarly journals Ce3+:CaSc2O4 Crystal Fibers for Green Light Emission: Growth Issues and Characterization

2014 ◽  
Vol 1655 ◽  
Author(s):  
Detlef Klimm ◽  
Jan Philippen ◽  
Toni Markurt ◽  
Albert Kwasniewski
Keyword(s):  
Melting Point ◽  
Light Emission ◽  
Green Light ◽  
Optical Emission ◽  
Charge Compensation ◽  
Scanning Calorimetry ◽  
Co Doping ◽  
Emission Growth ◽  
Crystal Fibers ◽  
Alkaline Oxides

ABSTRACTCe3+ is known to show broad optical emission peaking in the green spectral range. For the stabilization of 3-valent cerium in ceramic phosphors such as calcium scandate CaSc2O4, often co-doping with sodium for charge compensation is performed (Na+, Ce3+ ↔ 2 Ca2+). At the melting point of CaSc2O4 (≈2110°C), however, alkaline oxides evaporate completely and co-doping is thus no option for crystal growth from the melt. It is shown that even without co-doping Ce3+:CaSc2O4 crystal fibers can be grown from the melt by laser-heated pedestal growth (LHPG) in a suitable reactive atmosphere. Reactive means here that the oxygen partial pressure is a function of temperature and pO2(T) rises for this atmosphere in such a way that Ce3+ is kept stable for all T. Crystal fibers with ≈1 mm diameter and ≤50 mm length were grown and characterized. Differential thermal analysis (DTA) was performed in the pseudo-binary system CaO–Sc2O3, and the specific heat capacity cp(T) of CaSc2O4 was measured up to 1240 K by differential scanning calorimetry (DSC). Near and beyond the melting point of calcium scandate significant evaporation of calcium tends to shift the melt composition towards the Sc2O3 side. Measurements and thermodynamic calculations reveal quantitative data on the fugacities of evaporating species.

Azomethine ether-based potential curing agent for epoxy resin (diglycidyl ether of bisphenol A): Synthesis and characterization

2020 ◽  
pp. 009524432092857
Author(s):  
Fozia Noreen ◽  
Ahtaram Bibi ◽  
Naila Khalid ◽  
Imran Ullah Khan
Keyword(s):  
Spectral Analysis ◽  
Bisphenol A ◽  
Light Emission ◽  
Condensation Reaction ◽  
Stokes Shift ◽  
Green Light ◽  
Diglycidyl Ether ◽  
Proton Nuclear Magnetic Resonance ◽  
Curing Agent ◽  
Scanning Calorimetry

Novel azomethine ether-based compounds (A: N-((4-(9-(4-(phenylimino)methyl)phenoxy)nonyloxy)benzylidene)bezenamine and B: N-((4-(9-(4-(p-hydroxyphenylimino)methyl)phenoxy)nonyloxy)benzylidene)-4-hydroxybenzenamine) were synthesized by condensation reaction of dialdehyde, 4,4-(1,9-nonandiyle)bis(oxy)dibenzaldehyde with aromatic amines. Structures of synthesized compounds were successfully characterized by Fourier transform infrared (FTIR), ultraviolet–visible, proton nuclear magnetic resonance imaging and photoluminescence (PL) spectroscopy. The PL spectral analysis revealed that emission maxima of compounds A and B are at 475 and 500 nm, respectively, indicate blue and green light emission with large Stokes shift range (Δ λ ST, 109–138 nm). Two series of polymers: one azomethine-based polymers (C1–C5) and other without azomethine (H1–H4) were prepared by curing diglycidyl ether of bisphenol A with a synthesized curing agent (B) and commercial curing agent, respectively, in various proportions. The structural characterization of the resulting polymers was carried out by FTIR spectral analysis. Thermal properties revealed that azomethine-based polymers (C1–C5) were thermally stable up to 400°C as compared to H1–H4. The glass transition temperature of the polymers, determined by differential scanning calorimetry, was in the range 121–123°C.

scholarly journals Green Light Emission ofZnxCd1-xSeNanocrystals Synthesized by One-Pot Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Hong-Shuo Chen
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Light Emission ◽  
Green Light ◽  
Particle Size Effect ◽  
Partial Replacement ◽  
Face Centered Cubic ◽  
One Pot ◽  
Zn Content ◽  
High Emission

We present a facile one-pot synthesis to prepare ternaryZnxCd1-xSe(x= 0.2, 0.5, 0.8, and 1) nanocrystals (NCs) with high emission quantum yield (QY, 45~89%). The effect of Zn content (x) ofZnxCd1-xSeNCs on their physical properties is investigated. The NCs have a particle size of 3.2 nm and face centered cubic structure. However, the actual compositions of the NCs are Zn0.03Cd0.97Se, Zn0.11Cd0.89Se, and Zn0.38Cd0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. In terms of the optical properties, the emission wavelength shifts from 512 to 545 nm with increasing Zn content from 0 to 0.8 while the QY changes from 89 to 45, respectively. Partial replacement of Cd by Zn is beneficial to improve the QY of Zn0.2and Zn0.5NCs. The optical properties of ternary NCs are affected by compositional effect rather than particle size effect.

MICROSTRUCTURAL EVOLUTION OF Al-Cu-Mg-Ag ALLOY WITH TRACE Zr ADDITION DURING TWO-STEP HOMOGENIZATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 855-862 ◽  
Author(s):  
FEIYUE MA ◽  
ZHIYI LIU
Keyword(s):  
Melting Point ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Cast Alloy ◽  
Scanning Calorimetry ◽  
Zr Addition ◽  
Homogenization Time ◽  
The Matrix ◽  
Higher Temperature ◽  
Lower Temperature

The microstructural evolution in an Al - Cu - Mg - Ag alloy with trace Zr addition during homogenization treatment was characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). It was shown that the low-melting-point phase segregating toward grain boundaries is Al 2 Cu , with a melting point of 523.52°C. A two-step homogenization process was employed to optimize the microstructure of the as-cast alloy, during which the alloy was first homogenized at a lower temperature, then at a higher temperature. After homogenized at 420°C for 6 h, Al 3 Zr particles were finely formed in the matrix. After that, when the alloy was homogenized at an elevated temperature for a longer time, i.e., 515°C for 24 h, most of the precipates at the grain boundaries were removed. Furthermore, the dispersive Al 3 Zr precipitates were retained, without coarsening greatly in the final homogenization step. A kinetics model is employed to predict the optimal homogenization time at a given temperature theoretically, and it confirms the result in present study, which is 420°C/6h+515°C/24h.

scholarly journals Effect of the dispersion of the chromophore on the optical performances of polarizers from polyethylene and 5”-thio- (3-butyl)nonyl-2,2’:5’,2”-terthiophene

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Pucci ◽  
Letizia Moretto ◽  
Giacomo Ruggeri ◽  
Francesco Ciardelli
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Melting Point ◽  
Drawing Ratio ◽  
Scanning Calorimetry ◽  
Affine Deformation ◽  
Ultra High Molecular Weight ◽  
Scanning Electron

AbstractA new polyethylene-compatible terthiophene chromophore, 5”-thio-(3- butyl)nonyl-2,2’:5’,2”-terthiophene, with melting point lower than 0°C was prepared and used for linear polarizers based on ultra-high-molecular-weight polyethylene (UHMWPE). Differential scanning calorimetry and scanning electron microscopy indicate that the new chromophore is dispersed uniformly in films of UHMWPE obtained by casting from solution. The films show excellent dichroic properties (dichroic ratio 30) at rather low drawing ratio (≈ 20) . Moreover, qualitative agreement is observed with the Ward pseudo-affine deformation scheme.

Visible Light Emission from Erbium Doped Yttria Stabilized Zirconia

2003 ◽  
Vol 789 ◽  
Author(s):  
Michael Cross ◽  
Walter Varhue
Keyword(s):  
Band Gap ◽  
Light Emission ◽  
Green Light ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Rare Earth Ion ◽  
Device Structure ◽  
Insulating Layer ◽  
Light Emitting ◽  
Erbium Doped

ABSTRACT: One of the major shortcomings of silicon (Si) as a semiconductor material is its inability to yield efficient light emission. There has been a continued interest in adding rare earth ion impurities such as erbium (Er) to the Si lattice to act as light emitting centers. The low band gap of Si however has complicated this practice by quenching and absorbing this possible emission. Increasing the band gap of the host has been successfully tried in the case of gallium nitride (GaN) [1] and Si-rich oxide (SRO) [2] alloys. A similar approach has been tried here, where Er oxide (ErOx) nanocrystals have been formed in a yttria stabilized zirconia (YSZ) host deposited on a Si (100) substrate. The YSZ is deposited as a heteroepitaxial, insulating layer on the Si substrate by a reactive sputtering technique. The Er is also incorporated by a sputtering process from a metallic target and its placement in the YSZ host can be easily controlled. The device structure formed is a simple metal contact/insulator/phosphor sandwich. The device has been found to emit visible green light at low bias voltages. The advantage of this material is that it is much more structured than SiO2 which can theoretically lead to higher emission intensity.

High-efficiency circularly polarized green light emission from GaN-based laser diodes integrated with GaN metasurface quarterwave plate

2021 ◽  
Vol 119 (24) ◽  
pp. 241103
Author(s):  
Miao Wang ◽  
Yu Lin ◽  
Jue-Min Yi ◽  
De-Yao Li ◽  
Jian-Ping Liu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emission ◽  
Laser Diodes ◽  
Green Light ◽  
Circularly Polarized ◽  
Green Light Emission

scholarly journals Electroluminescence and photo-response of inorganic halide perovskite bi-functional diodes

Nanophotonics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 1981-1988 ◽  
Author(s):  
Ning Li ◽  
Ying Suet Lau ◽  
Yanqin Miao ◽  
Furong Zhu
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Light Emission ◽  
Forward Bias ◽  
Green Light ◽  
Visible Light Communication ◽  
Light Emitting ◽  
Response Characteristics ◽  
Photo Response ◽  
Halide Perovskite

AbstractIn this work, we report our efforts to develop a novel inorganic halide perovskite-based bi-functional light-emitting and photo-detecting diode. The bi-functional diode is capable of emitting a uniform green light, with a peak wavelength of 520 nm, at a forward bias of >2 V, achieving a high luminance of >103 cd/m2 at 7 V. It becomes an efficient photodetector when the bi-functional diode is operated at a reverse bias, exhibiting sensitivity over a broadband wavelength range from ultraviolet to visible light. The bi-functional diode possesses very fast transient electroluminescence (EL) and photo-response characteristics, e.g. with a short EL rising time of ~6 μS and a photo-response time of ~150 μS. In addition, the bi-functional diode also is sensitive to 520 nm, the wavelength of its peak EL emission. The ability of the bi-functional diodes for application in high speed visible light communication was analyzed and demonstrated using two identical bi-functional diodes, one performed as the signal generator and the other acted as a signal receiver. The dual functions of light emission and light detection capability, enabled by bi-functional diodes, are very attractive for different applications in under water communication and visible light telecommunications.

Blue-Green Light Emission from Self-Assembled Bipyridinium Thin Films

1998 ◽  
Vol 27 (9) ◽  
pp. 909-910 ◽  
Author(s):  
Haipeng Zheng ◽  
Ruifeng Zhang ◽  
Ying Wu ◽  
Jiacong Shen
Keyword(s):  
Thin Films ◽  
Light Emission ◽  
Green Light ◽  
Green Light Emission ◽  
Self Assembled

scholarly journals Luminescence of SiO2-BaF2:Tb3+, Eu3+ Nano-Glass-Ceramics Made from Sol–Gel Method at Low Temperature

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 259
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Three Dimensional ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Scanning Calorimetry ◽  
Light Emitting ◽  
Co Doping ◽  
Dsc Measurements ◽  
Decay Times

The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE3+) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF2 nanocrystals co-doped with Tb3+, Eu3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol–gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol–gel materials was carried out by excitation and emission spectra along with decay analysis from the 5D4 level of Tb3+. As a result, the visible light according to the electronic transitions of Tb3+ (5D4 → 7FJ (J = 6–3)) and Eu3+ (5D0 → 7FJ (J = 0–4)) was recorded. It was also observed that co-doping with Eu3+ caused the shortening in decay times of the 5D4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb3+/Eu3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.

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