scholarly journals Excitation-Independent Emission of Carbon Quantum Dot Solids

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Xuan-Dung Mai ◽  
Yen Thi Hai Phan ◽  
Van-Quang Nguyen
Keyword(s):  
Solid State ◽  
Solvothermal Method ◽  
Blue Emission ◽  
Carbon Quantum Dots ◽  
Solid State Lighting ◽  
Optical And Electrical Properties ◽  
Red Emission ◽  
Solid Films ◽  
Carbon Quantum Dot ◽  
S States

Solid assemblies of carbon quantum dots (CQDs) are important for diverse applications including LEDs, solar cells, and photosensors; their optical and electrical properties have not been explored yet. Herein, we used amphiphilic CQDs synthesized from citric acid and thiourea by a solvothermal method to fabricate CQD solid films. Optical properties of CQDs studied by UV-Vis and photoluminescence spectroscopies indicate that CQDs possess three different emission centers at 425 nm, 525 nm, and 625 nm originating from C sp2 states, N-states, and S-states, respectively. In a solid state, π-π stacking quenched the blue emission, while the red emission increased. Importantly, CQD films exhibited excitation independence, which is important to design solid-state lighting applications.

Blue Upconversion Luminescence from Phosphor Tm3+/Yb3+ Co-Doped Gd2Mo3O9

2013 ◽  
Vol 683 ◽  
pp. 3-6
Author(s):  
Jia Yue Sun ◽  
Bing Xue ◽  
Guang Chao Sun ◽  
Dian Peng Cui ◽  
Hai Yan Du
Keyword(s):  
Solid State ◽  
Upconversion Luminescence ◽  
Blue Emission ◽  
Solid State Reaction Method ◽  
Solid State Lighting ◽  
Red Emission ◽  
Reaction Method ◽  
X Ray ◽  
Strong Blue Emission ◽  
Co Doped

The upconversion (UC) luminescence properties of phosphor Tm3+/Yb3+co-doped Gd2Mo3O9were investigated in detail. Tm3+/Yb3+co-doped Gd2Mo3O9was prepared by solid-state reaction method using Na2CO3as flux and characterized by powder X-ray diffractometry. Under 980nm excitation, Tm3+/Yb3+co-doped Gd2Mo3O9has exhibited a weak red emission near 651nm and strong blue emission at 476nm. Tm3+/Yb3+co-doped Gd2Mo3O9phosphor has been considered as a better candidate in solid-state lighting applications.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

Intense multi-state visible absorption and full-color luminescence of nitrogen-doped carbon quantum dots for blue-light-excitable solid-state-lighting

2016 ◽  
Vol 4 (38) ◽  
pp. 9027-9035 ◽  
Author(s):  
Daqin Chen ◽  
Weiwei Wu ◽  
Yongjun Yuan ◽  
Yang Zhou ◽  
Zhongyi Wan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solid State ◽  
Carbon Quantum Dots ◽  
Solid State Lighting ◽  
Visible Absorption ◽  
Nitrogen Doped ◽  
Full Color ◽  
Potential Applications ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon dots with multi-state visible absorption and full-color blue/yellow/red emissions are synthesized, and show potential applications in solid-state-lighting.

Novel Mn4+-activated layered oxide-fluoride perovskite-type KNaMoO2F4 red phosphor for wide gamut warm white light-emitting diodes backlight

2021 ◽  
Author(s):  
Jiao Wu ◽  
Bo Wang ◽  
Zhiyuan Liu ◽  
Kang Zhang ◽  
Xiaoshuang Li ◽  
...  
Keyword(s):  
Solid State ◽  
White Light ◽  
Light Emitting Diodes ◽  
Solid State Lighting ◽  
Red Phosphor ◽  
Red Emission ◽  
Light Emitting ◽  
Warm White Light ◽  
White Light Emitting Diodes ◽  
Perovskite Type

Mn4+-activated oxidefluoride phosphors are attractive for application in wide solid-state lighting devices because of its distinct red emission at about 630 nm and the abundant storage of Mn4+ ion. However,...

Spectroscopic behavior of Eu3+ in SnO2 for tunable red emission in solid state lighting devices

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 51102-51109 ◽  
Author(s):  
M. Chowdhury ◽  
S. K. Sharma
Keyword(s):  
Solid State ◽  
Spectroscopic Investigation ◽  
Solid State Lighting ◽  
Red Emission ◽  
Spectroscopic Behavior

This paper reports a spectroscopic investigation of Eu3+ doped SnO2 nanoparticles.

Host-sensitized luminescence properties of KLa5O5(VO4)2:Eu3+ for solid-state lighting applications

2016 ◽  
Vol 4 (30) ◽  
pp. 7277-7285 ◽  
Author(s):  
Marie Colmont ◽  
Sébastien Saitzek ◽  
Arturas Katelnikovas ◽  
Houria Kabbour ◽  
Jacob Olchowka ◽  
...  
Keyword(s):  
Solid State ◽  
Blue Emission ◽  
Solid State Synthesis ◽  
Solid State Lighting ◽  
Luminescence Properties ◽  
Sensitized Luminescence ◽  
Synthesis Route ◽  
Uv Excitation

K1La5−xEuxO5(VO4)2 compounds were prepared by a solid state synthesis route. Their luminescence properties were studied. The non-substituted sample that exhibits blue emission under UV excitation switched to orange/red as soon as a small amount of europium is inserted in the phosphor.

scholarly journals Effect of Eu3+Concentration on the Luminescent Properties of SrTiO3Phosphors Prepared by Pressure-Assisted Combustion Synthesis

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
C. R. García ◽  
J. Oliva ◽  
M. T. Romero ◽  
R. Ochoa-Valiente ◽  
L. A. Garcia Trujillo
Keyword(s):  
Solid State ◽  
Combustion Synthesis ◽  
Luminescent Properties ◽  
Solid State Lighting ◽  
Sem Images ◽  
Red Emission ◽  
Red Phosphors ◽  
Field Emission Displays ◽  
Potential Applications

This work presents the structural, morphological, and luminescent characterization of pure SrTiO3and SrTiO3:Eu3+powders doped with different europium atomic concentrations from 3.0 to 7.0 a.t.%. Those phosphors were prepared by pressure-assisted combustion synthesis using titanium oxide as precursor and were subjected to postannealing at 1200°C. XRD measurements indicated that undoped and Eu3+doped samples presented a single cubic crystalline phase and SEM images demonstrated that we have particles with sizes in the range of 0.2 µm–1.0 µm. Moreover, the size of the grains increases as the content of Eu3+dopant increases. A strong red emission from Eu3+ions was obtained by photoluminescence under excitation at 396 nm and confirmed by cathodoluminescence. All those results indicate that our red phosphors could be useful for potential applications in solid state lighting and field emission displays.

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