Synthesis and Characterization of Lightweight Beryllium Chloro Silicate Phosphor

2022 ◽  
pp. 89-100
Author(s):  
Khushbu Sharma
Keyword(s):  
Blue Emission ◽  
Emission Peak ◽  
Excitation Band ◽  
Photoluminescence Spectra ◽  
Strong Emission ◽  
White Leds ◽  
Long Afterglow ◽  
Silicate Phosphor ◽  
Low Weight

In this chapter, low weight barium-based cholorsilicate Ba5Cl6Si2O6:Eu2+ is prepared through a solid-state reaction. To confirm the structure of the synthesized phosphors, powder photographs were obtained using an x-ray diffractometer. Photoluminescence spectra and FTIR spectra were recorded. Photoluminescence spectra are studied. The emission peak is observed at 407 nm at excitation 275 nm. The intense violet-blue emission is obtained. The broad excitation band and strong emission indicate that Ba5Cl6Si2O6:Eu2+could be a good phosphor candidate for blue LED and white LEDs. Decay curve indicates the phosphor has a long afterglow feature.

Luminescence Reducing Mechanism of Cd Doped Y2O2S:Ti,Cd Long Afterglow Phosphor

2007 ◽  
Vol 336-338 ◽  
pp. 604-606
Author(s):  
Peng Yue Zhang ◽  
Zhang Lian Hong ◽  
Xian Ping Fan ◽  
Min Quan Wang
Keyword(s):  
Solid State ◽  
Trap Depth ◽  
Emission Peak ◽  
Trap Level ◽  
Structure Defect ◽  
Photoluminescence Spectra ◽  
Ion Content ◽  
Long Afterglow ◽  
Chromaticity Coordinate ◽  
Co Doped

Y1.97-xTi0.03CdxO2S (0≤x≤0.06) phosphors with long afterglow were synthesized by solid-state reaction. The photoluminescence spectra, decay curves, thermoluminescnece spectra and Chromaticity coordinate curves were investigated. Results showed that the luminescence and afterglow intensity of Y1.97-xTi0.03CdxO2S (0≤x≤0.06) reduced gradually with increasing Cd2+ ion content while the shape and position of emission peak remain unchanged. The Chromaticity coordinate of present phosphor keeps at (0.5497,0.4415). Furthermore, based on the results of thermoluminescence curves of Ti, Cd single doped and co-doped Y2O2S phosphors, the doped Cd ion reduces the inherent trap depth of Ti single doped Y2O2S:Ti, and induces simultaneously a new trap level in Y2O2S:Ti,Cd phosphor. Thus, it was proposed that the introduced new structure defect by Cd2+ ions should be responsible for the reducing luminescence and afterglow property.

Synthesis and blue emission properties of Co-doped CdS semiconductor nanoparticles

2021 ◽  
Vol 01 ◽  
Author(s):  
Sangaraju Sambasivam ◽  
Yedluri Anil Kumar ◽  
Chandu V.V. Muralee Gopi ◽  
Venkatesha Narayanaswamy ◽  
Ihab M. Obaidat
Keyword(s):  
Band Gap ◽  
Blue Emission ◽  
Semiconductor Nanoparticles ◽  
Emission Peak ◽  
Photoluminescence Spectra ◽  
Blue Emission Peak ◽  
Cubic Structure ◽  
Strong Blue Emission ◽  
Xrd And Tem ◽  
Co Doped

Background: Cadmium sulfide (CdS) based semiconductors are of great interest for different high-end applications because it poses direct bandgap (2.42 eV). CdS are the primary constituent material in many applications, namely solar cells, electroluminescent, and quantum dot light-emitting diodes. Transition metal-doped CdS revealed considerable influence in the bandgap, photoluminescence properties, and peak energy upon increasing the metal content. Objective: In this work, we study the single-phase cubic structure of CdS. Photoluminescence spectra revealed a strong blue emission peak located at about 445 nm. Methods: We investigate the Co-doping CdS semiconductor nanoparticles prepared via the chemical co-precipitation method using thiophenol as a template, 300 °C/2h in vacuum optimum temperature, and annealing period to yield nanosized particles. Morphology and structural studies of the particles were using XRD and TEM, respectively. Results: XRD and TEM studies for the calcined samples revealed a cubic structure. The crystalline size was in the range of 10-17 nm. Thermo gravimetric analysis (TGA) was employed to stabilize the temperature of annealing for the samples. Photoluminescence spectra revealed a strong blue emission peak around 445 nm, indicating surface states within the band gap region, a characteristic feature of nanoparticles. The blue shift in the spectra and the band gap value of Co-doped CdS nanoparticles was estimated using UV-vis absorption spectra. Conclusion: XRD analysis indicated zinc blende structure, and the intensity decreased with increasing Co content. TEM images show that the particles are spherical with average sizes around 13 nm. Luminescence of the synthesized nanoparticles exhibited blue emission between 400 – 500 nm, with the peak located at about 445 nm. The emission intensity increased with the increase in Co concentration.

Preparation of a New Red Long Afterglow Phosphor Strontium Aluminate Composition

2007 ◽  
Vol 336-338 ◽  
pp. 616-618 ◽  
Author(s):  
Ping Zhang ◽  
Ming Xia Xu ◽  
Jin Wei Zhao ◽  
Yu Xing Qin ◽  
Yi Wei Lv
Keyword(s):  
Broad Emission Band ◽  
Visible Range ◽  
Excitation Band ◽  
Photoluminescence Spectra ◽  
Strontium Aluminate ◽  
Excitation Light ◽  
Naked Eye ◽  
Reducing Atmosphere ◽  
Long Afterglow ◽  
Broad Emission

A new red afterglow phosphor Sr3Al2O6: Eu2+, Dy3+ was synthesized by solid-state reaction and sintered at 1150°C for 2h in reducing atmosphere. Red long lasting phosphorescence of the prepared materials is observed in the dark with naked eye after the removal of the excitation light. From the photoluminescence spectra, the broad emission band centered at 612 nm is confirmed. Excitation band chiefly lies in visible range and its maximum peak is at 473nm. Luminescence mechanism is studied.

Blue Emitting BaAl2O4:Ce3+ Nanophosphors with High Color Purity and Brightness for White LEDs

2019 ◽  
Vol 25 (6) ◽  
pp. 1466-1470 ◽  
Author(s):  
Rituparna Chatterjee ◽  
Subhajit Saha ◽  
Karamjyoti Panigrahi ◽  
Uttam Kumar Ghorai ◽  
Gopes Chandra Das ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Sol Gel ◽  
Blue Emission ◽  
Diffraction Field ◽  
White Leds ◽  
Display Devices ◽  
Transmission Electron ◽  
Structure Morphology ◽  
The Impact

AbstractIn this work, strongly blue emitting Ce3+-activated BaAl2O4 nanophosphors were successfully synthesized by a sol–gel technique. The crystal structure, morphology, and microstructure of the nanophosphors have been studied by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The photoluminescence spectra show the impact of concentration variation of Ce3+ on the photoluminescence emission of the phosphor. These nanophosphors display intense blue emission peaking at 422 nm generated by the Ce3+ 5d → 4f transition under 350 nm excitation. Our results reveal that this nanophosphor has the capability to take part in the emergent domain of solid-state lighting and field-emission display devices.

Fabrication and Properties of Zinc Silicate Phosphors through Solid State Reaction

2010 ◽  
Vol 160-162 ◽  
pp. 594-598
Author(s):  
Guo Jian Jiang ◽  
Jia Yue Xu ◽  
Hui Shen ◽  
Yan Zhang ◽  
Lin He Xu ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Emission Peak ◽  
Zinc Silicate ◽  
Red Phosphor ◽  
Reaction Method ◽  
Long Afterglow ◽  
Luminescent Mechanism ◽  
Silicate Phosphors

Zinc silicate-based (Zn2SiO4:Eu3+) long afterglow phosphors were produced by solid state reaction method. The effects of borax and Eu2O3 additive on the properties of fabricated products have been studied. The results show that, there is not much difference in phase compositions within the borax additive amount; however, their SEM morphologies are different. Borax additive can increase the grain size of the product. Some sintering phenomena could be observed in the sample with Eu2O3 addition. The fluorescence spectroscopy results indicate that, the emission peak of the sample with Eu3+ additive located at 612nm, which may be a good candidate for red phosphor applications. The luminescent mechanism of Zn2SiO4:Eu3+ is also discussed.

Photoluminescence Characterization of SiGe/Si Quantum-Well Wire Structures

1995 ◽  
Vol 379 ◽  
Author(s):  
S. Nilsson ◽  
H. P. Zeindl ◽  
A. Wolff ◽  
K. Pressel
Keyword(s):  
Quantum Well ◽  
Room Temperature ◽  
Molecular Beam ◽  
Optical Quality ◽  
Photoluminescence Spectra ◽  
Single Quantum Well ◽  
Quantum Well Wire ◽  
Carbon Interstitial

ABSTRACTLow-temperature photoluminescence measurements were performed in order to probe the optical quality of SiGe/Si quantum-well wire structures fabricated by electron-beam lithography and subsequent reactive ion etching, having the patterned polymethylmethacrylate resist as an etch mask. In addition, one set of quantum-well wire structures was post-treated by means of annealing in a hydrogen environment. Our results show that even for the smallest wires of about 100nm in width, the wires exhibit phonon-resolved photoluminescence spectra, similar to that from the molecular beam eptitaxially grown SiGe single quantum well which was used as starting material for the patterning process. After the patterning process a new sharp peak appears in the photoluminescence spectra at 0.97eV in photon energy. Our investigation suggests that this feature is introduced by damage during the patterning process and most probably identical to the G-line, which previously was identified as originating from the dicarbon centre (substitutional carbon-interstitial carbon) in Si. This centre is known to be a very common endproduct of irradiating Si near room temperature which is the case at our patterning process.

A novel red emitting phosphor LiBaB9 O15 :Sm2+ /Sm3+ , li+ with broad excitation band for white LEDs

Luminescence ◽  
2018 ◽  
Vol 33 (2) ◽  
pp. 438-442 ◽  
Author(s):  
Ting Li ◽  
Zhijun Wang ◽  
Panlai Li ◽  
Shuchao Xu ◽  
Qiongyu Bai ◽  
...  
Keyword(s):  
Excitation Band ◽  
Broad Excitation Band ◽  
White Leds ◽  
Red Emitting Phosphor

scholarly journals New Ni-Anthracene Complex for Selective and Sensitive Detection of 2,4,6-Trinitrophenol

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Kumbam Lingeshwar Reddy ◽  
Anabathula Manoj Kumar ◽  
Abhimanew Dhir ◽  
Venkata Krishnan
Keyword(s):  
Homeland Security ◽  
High Selectivity ◽  
Weak Acid ◽  
Simple Approach ◽  
Emission Peak ◽  
Sensitive Detection ◽  
Strong Emission ◽  
Explosive Materials ◽  
Quenching Efficiency ◽  
Strong Emission Peak

Selective and sensitive detection of explosive materials through a simple approach is an attractive area of research having implications on public safety and homeland security. Considering this implication in mind, a new Ni-anthracene complex was designed and synthesized and has been demonstrated as an efficient fluorescence chemosensor for the selective and sensitive detection of 2,4,6-trinitrophenol. Firstly, a fluorescent anthracene ligand (A) was synthesized by treating anthracene-9-carboxaldehyde with 1,3-diaminopropane in presence of a weak acid. To achieve superior selectivity and great quenching efficiency for 2,4,6-trinitrophenol (TNP), a Ni complex, namely, [Ni(μ2-L)(NO3)] (B), was synthesized via the reaction of A with Ni(NO3)2·6H2O. Complex B showed strong emission peak (λmax) at 412 nm and exhibited high selectivity towards TNP among other nitroaromatics and anions. 100 equivalents of TNP made 95% fluorescence quenching of B and its detection limit for TNP was calculated as 2.8 μM.

scholarly journals Near UV-Blue Excitable Green-Emitting Nanocrystalline Oxide

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
C. E. Rodríguez-García ◽  
N. Perea-López ◽  
G. A. Hirata
Keyword(s):  
Broad Band ◽  
Emission Peak ◽  
Electronic Transitions ◽  
Excitation Band ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Pl Emission ◽  
Intense Broad Band ◽  
Nanocrystalline Oxide

Green-emitting Eu-activated powders were produced by a two-stage method consisting of pressure-assisted combustion synthesis and postannealing in ammonia. The as-synthesized powders exhibited a red photoluminescence (PL) peak located at  nm when excited with  nm UV. This emission peak corresponds to the5D0→7F2transition in Eu3+. After annealing in ammonia, the PL emission changed to an intense broad-band peak centered at  nm, most likely produced by 4f65d1→4f7electronic transitions in Eu2+. This green-emitting phosphor has excitation band in the near UV-blue region (–450 nm). X-ray diffraction analysis reveals mainly the orthorhombic EuAlO3and Al2O3phases. Transmission electron microscopy observations showed that the grains are formed by faceted nanocrystals (~4 nm) of polygonal shape. The excellent excitation and emission properties make these powders very promising to be used as phosphors in UV solid-state diodes coupled to activate white-emitting lamps.

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