scholarly journals Tunable white light emission by variation of composition and defects of electrospun Al2O3–SiO2 nanofibers

2015 ◽  
Vol 6 ◽  
pp. 313-320 ◽  
Author(s):  
Jinyuan Zhou ◽  
Gengzhi Sun ◽  
Hao Zhao ◽  
Xiaojun Pan ◽  
Zhenxing Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
White Light ◽  
Composite Nanofibers ◽  
Light Emission ◽  
Blue Emission ◽  
Green Emission ◽  
White Light Emission ◽  
Transmission Electron ◽  
The Individual ◽  
White Luminescence

Composite nanofibers consisting of Al2O3–SiO2 were prepared by electrospinning in combination with post-calcination in air. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to investigate the crystalline phase and microstructure of the composite nanofibers. Photoluminescence experiments indicated that the resulting white light emission can be tuned by the relative intensity of the individual spectral components, which are related to the individual defects such as: violet-blue emission from O defects, green emission from ≡Si(Al)–O–C∙=O, and red emission from intersystem radiative crossing. White light emission was realized at a Al/(Al–Si) ratio of 40 and 60 mol %. This research may offer a deeper understanding of the preparation of efficient and environmentally friendly, white luminescence materials.

scholarly journals Energy transfer-mediated white light emission from Nile red-doped 9,10-diphenylanthracene nanoaggregates upon excitation with near UV light

2019 ◽  
Vol 18 (11) ◽  
pp. 2748-2758 ◽  
Author(s):  
Biswajit Manna ◽  
Amitabha Nandi ◽  
Rajib Ghosh
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Light Emission ◽  
Uv Light ◽  
Nile Red ◽  
Blue Emission ◽  
Green Emission ◽  
White Light Emission ◽  
Bright White Light ◽  
Red Lead

The excitonic blue emission, excimeric green emission and energy transfer-mediated red emission of Nile red lead to bright white light emission upon the photoexcitation of Nile red-doped DPA nanoaggregates.

Near white light emission from ZnO nanostructures

2011 ◽  
Vol 1303 ◽  
Author(s):  
Sanjaya Brahma ◽  
P. Jaiswal ◽  
K. K. Nanda ◽  
L. M. Kukreja ◽  
S.A. Shivashankar
Keyword(s):  
Electron Microscopy ◽  
White Light ◽  
Light Emission ◽  
Color Space ◽  
White Light Emission ◽  
Blue Laser ◽  
Excitation Source ◽  
Zno Nanostructures ◽  
Structure Directing Agent ◽  
Yellow Region

ABSTRACTWe report white light emission from ZnO nanostructures in powder form, prepared by microwave irradiation-assisted chemical synthesis, in the presence of a structure directing agent. Determination of their crystallinity, actual shape, and orientation was made using X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and optical properties have been studied through photoluminescence (PL), measured using He-Cd laser (325 nm) as the excitation source. There is a noticeable variation in the luminescence correlated with variation of process parameters, such as microwave power, duration of irradiation, and the type/concentration of surfactants. The CIE (Commission Internationale l’Eclairage) diagram shows that the luminescence lies in yellow region of the color space. As the luminescence from the powder of ZnO lies in the yellow region, it is possible to produce white light from the powder of ZnO by using a blue laser as the excitation source.

scholarly journals Indium-antimony-halide single crystals for high-efficiency white-light emission and anti-counterfeiting

2021 ◽  
Vol 7 (34) ◽  
pp. eabg3989
Author(s):  
Jun-Hua Wei ◽  
Jin-Feng Liao ◽  
Lei Zhou ◽  
Jian-Bin Luo ◽  
Xu-Dong Wang ◽  
...  
Keyword(s):  
Single Crystals ◽  
White Light ◽  
High Performance ◽  
High Efficiency ◽  
Light Emission ◽  
Blue Emission ◽  
White Light Emission ◽  
Information Storage ◽  
Yellow Emission ◽  
Bright White Light

Although single-source white emissive perovskite has emerged as a class of encouraging light-emitting material, the synthesis of lead-free halide perovskite materials with high luminous efficiency is still challenging. Here, we report a series of zero-dimensional indium-antimony (In/Sb) alloyed halide single crystals, BAPPIn2–2xSb2xCl10 (BAPP = C10H28N4, x = 0 to 1), with tunable emission. In BAPPIn1.996Sb0.004Cl10, bright yellow emission with near 100% photoluminescence quantum yield (PLQY) is yielded when it was excited at 320 nm, which turns into bright white-light emission with a PLQY of 44.0% when excited at 365 nm. Combined spectroscopy and theoretical studies reveal that the BAPP4+-associated blue emission and inorganic polyhedron–afforded orange emission function as a perfect pair of complementary colors affording white light in BAPPIn1.996Sb0.004Cl10. Moreover, the interesting afterglow behavior, together with excitation-dependent emission property, makes BAPPIn2–2xSb2xCl10 as high-performance anti-counterfeiting/information storage materials.

PHOTOLUMINESCENCE SPECTRA AND MAGNETIC PROPERTIES OF HYDROTHERMALLY SYNTHESIZED MnO2 NANORODS

2013 ◽  
Vol 27 (29) ◽  
pp. 1350211 ◽  
Author(s):  
ARBAB MOHAMMAD TOUFIQ ◽  
FENGPING WANG ◽  
QURAT-UL-AIN JAVED ◽  
QUANSHUI LI ◽  
YAN LI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Blue Emission ◽  
Green Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Uv Emission ◽  
Transmission Electron

In this paper, single crystalline tetragonal MnO 2 nanorods have been synthesized by a simple hydrothermal method using MnSO 4⋅ H 2 O and Na 2 S 2 O 8 as precursors. The crystalline phase, morphology, particle sizes and component of the as-prepared nanomaterial were characterized by employing X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). The photoluminescence (PL) emission spectrum of MnO 2 nanorods at room temperature exhibited a strong ultraviolet (UV) emission band at 380 nm, a prominent blue emission peak at 453 nm as well as a weak defect related green emission at 553 nm. Magnetization (M) as a function of applied magnetic field (H) curve showed that MnO 2 nanowires exhibited a superparamagnetic behavior at room temperature which shows the promise of synthesized MnO 2 nanorods for applications in ferrofluids and the contrast agents for magnetic resonance imaging. The magnetization versus temperature curve of the as-obtained MnO 2 nanorods shows that the Néel transition temperature is 94 K.

Optical Properties and White Emission from Dy3+ Doped in Y2O3-CaO-SiO2-B2O3 Glasses

2016 ◽  
Vol 702 ◽  
pp. 62-65 ◽  
Author(s):  
Natthakridta Chanthima ◽  
Yotsakit Ruangtaweep ◽  
Jakrapong Kaewkhao
Keyword(s):  
Optical Properties ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
White Light Emission ◽  
Melt Quenching ◽  
Molar Composition ◽  
White Emission ◽  
Quenching Method ◽  
Luminescent Spectra

The Dy3+ doped Y2O3-CaO-SiO2-B2O3 glasses with molar composition 25Y2O3 : 10CaO : 10SiO2 : (55-x)B2O3, where x is 0.0 to 0.5 mol%, have been prepared by melt quenching method and are characterized through absorption, photoluminescence and decay analysis. From the luminescent spectra, observed a strong yellow and blue emission from 4F9/2→ 6H13/2 (575 nm) and 4F9/2 → 6H15/2 (482 nm) transition of Dy3+ ions respectively. The tunable white light emission at different excitation wavelengths are investigated through CIE 1931 diagram. The decay curves show the decreasing of lifetimes when addition of Dy2O3 concentration.

scholarly journals Fabrication and Characterization of a Light-Emitting Device Based on the CdS/ZnS Spherical Quantum Dots

2021 ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
Critical Factor ◽  
White Light Emission ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

Abstract In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of ITO/ ZnO / QD / CBP/ MoO 3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

scholarly journals Fabrication of a light-emitting device based on the CdS/ZnS spherical quantum dots

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
White Light Emission ◽  
Core Shell ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

AbstractIn this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of FTO/ ZnO / QD / CBP/ MoO3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums for core/shell structures get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

scholarly journals Nucleotide-based green synthesis of lanthanide coordination polymers for tunable white-light emission

2020 ◽  
Vol 9 (1) ◽  
pp. 578-585
Author(s):  
Yaoyao Zhang ◽  
Baoxia Liu ◽  
Qi Shen ◽  
Xiuhua Wei ◽  
Yanli Zhou ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Coordination Polymers ◽  
White Light ◽  
Light Emission ◽  
Synthesis Method ◽  
Adenosine Monophosphate ◽  
White Light Emission ◽  
Lanthanide Ions ◽  
Light Emitting ◽  
Transmission Electron

AbstractWhite-light emitting lanthanide(iii) metal-organic coordination polymers (LMOCPs) were prepared via a green synthesis method performed in pure aqueous solution at room temperature without using toxic solvent and reagents. This kind of LMOCP, denoted as adenosine monophosphate (AMP)/Ln-CIP, was composed of Ln3+ {Ln = Tb (1), Eu (2), and Gd (3)}, hydrosoluble biomolecule of AMP, and nonpoisonous antenna ligand of CIP (ciprofloxacin). The complex of Tb(1), Eu(2), and Gd(3) in AMP/Ln-CIP emits strong green, red, and blue light, respectively. With careful adjustment of the doping mole ratio of the three lanthanide ions {Ln = Tb:Eu:Gd = 0.1:0.9:99.0} in one framework, white light-emission can indeed be achieved. AMP/Ln-CIP is network-structural and amorphous by transmission electron microscope and X-ray diffraction analysis. The fluorescence lifetime and quantum yield of AMP/Ln-CIP are 4.36 ms and 36.5%, respectively.

Dy3+ doped LaInO3: A host-sensitized white luminescence phosphor with exciton-mediated energy transfer

2021 ◽  
Author(s):  
Tao Hu ◽  
Lei Xia ◽  
Wen Liu ◽  
Jiyang Xie ◽  
Zuimin Jiang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rare Earth ◽  
White Light ◽  
Single Phase ◽  
Light Emission ◽  
White Light Emission ◽  
The Self ◽  
Energy Transfer Mechanism ◽  
Rare Earth Ion ◽  
White Luminescence

Host-sensitized rare-earth-ion lighting has emerged as a promising route to realize single-phase white-light emission due to effectively overcoming the self-absorption problems within multiple phosphors. However, the involved energy transfer mechanism...

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