scholarly journals Color change upconversion mechanism of Y-=SUB=-6-=/SUB=-O-=SUB=-5-=/SUB=-F-=SUB=-8-=/SUB=-:Er-=SUB=-3+-=/SUB=-/Yb-=SUP=-3+-=/SUP=- microtubes by using time-resolve spectra -=SUP=-*-=/SUP=-

2018 ◽  
Vol 60 (7) ◽  
pp. 1370
Author(s):  
S. Wang ◽  
X.H. Cheng ◽  
J.Y. Wang ◽  
Z.C. Zhong
Keyword(s):  
Color Change ◽  
Green Emission ◽  
Luminescent Properties ◽  
Red Emission ◽  
Prepared Sample ◽  
Upconversion Mechanism ◽  
Back Transfer

AbstractThe mechanism of the upconversion processes in Y_6O_5F_8: 2%Er^3+/ X %Yb^3+ ( X = 3, 10, 20) microtubes has been explored. The luminescent properties of the as prepared sample is investigated by utilizing up- /downconversion, decay and time resolve spectra. The results indicate that the red and green emission are clearly competitive depending on the Yb^3+ concentration. High Yb^3+ concentration induces the enhancement of the energy-back-transfer (EBT), process, which leads to the quenching of green emission and enhances the red emission. So it is possible to utilize the temporal evolutions of emission bands to deeply understand the color change UC mechanisms.

Tuning Upconversion Emission of -NaGdF4:Yb3+/Ho3+ Nanorods Through Yb3+

2016 ◽  
Vol 16 (4) ◽  
pp. 3754-3758 ◽  
Author(s):  
Fangqi Gao ◽  
Wei Gao ◽  
Ruibo Wang ◽  
Longxiang Yan ◽  
Jinping Li ◽  
...  
Keyword(s):  
Sample Size ◽  
Relaxation Process ◽  
Solvothermal Method ◽  
Fluorescence Emission ◽  
Green Emission ◽  
Upconversion Emission ◽  
Cross Relaxation ◽  
Red Emission ◽  
Cross Relaxation Process ◽  
Upconversion Mechanism

Yb3+/Ho3+ doped hexagonal NaGdF4 nanocrystals are synthesized through solvothermal method, for which pure hexagonal phased nanorods are presented. The concentration influence of Yb3+ ions on the sample morphology and fluorescence emission of Ho3+ is investigated. It is found that the sample size is changed from 25 nm to 125 nm and the upconversion emission is tuned from green to yellow when the concentration of Yb3+ ions is increased from 5.0 mol% to 50.0 mol%. The possible upconversion mechanism and the improvement of crystallinity are carefully investigated. It is suggested that the cross-relaxation process between Ho3+ ions promotes the red emission and quenches the green emission.

Dual-mode conversion luminescent properties of PbF2:Er3+, Yb3+ phosphors

2019 ◽  
Vol 12 (03) ◽  
pp. 1950033
Author(s):  
Hong-Wei Liu ◽  
Jia-Liang Sun ◽  
Yi-Fan Wang ◽  
Xiao-Yi Ma ◽  
Biao Li ◽  
...  
Keyword(s):  
Mode Conversion ◽  
Energy Levels ◽  
Green Emission ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Enhancement Effect ◽  
X Ray Diffraction ◽  
Dual Mode ◽  
Red Emission ◽  
Source Excitation

PbF2: Er[Formula: see text], Yb[Formula: see text] phosphors with the property of dual-mode conversion were prepared successfully by the high-temperature solid-state reaction method. The structure and luminescence properties of the samples were characterized by X-ray diffraction (XRD) and fluorescence spectrum method. The luminescence mechanisms of the samples under single ultraviolet (UV) or infrared (IR) light source excitation and UV[Formula: see text]IR co-excitation were analyzed. Under 376, 980 and 1550[Formula: see text]nm excitation, the phosphors showed intense green and red emission, the green emission (520–570[Formula: see text]nm) and the red emission (650–680[Formula: see text]nm) originated from the 2H[Formula: see text]I[Formula: see text], 4S[Formula: see text]I[Formula: see text] and 4F[Formula: see text]I[Formula: see text] transitions of Er[Formula: see text] ions, respectively. The fluorescence enhancement effect was observed in the UV and IR co-excited samples, which is derived from the infrared photon reabsorption of the ions at metastable energy levels.

Fabrication of Bifunctional SiO2/Europium-Polyoxometalates/Ag Particles and their Luminescence and Catalysis Properties

2013 ◽  
Vol 575-576 ◽  
pp. 216-224
Author(s):  
Jun Wang ◽  
Shao Hua Fan ◽  
Wei Qian Zhao ◽  
Wu Ke Li ◽  
Xue Lian Lu
Keyword(s):  
Main Product ◽  
Catalytic Properties ◽  
Uv Light ◽  
Luminescent Properties ◽  
Silica Spheres ◽  
Hybrid Particles ◽  
Red Emission ◽  
Transmission Electron ◽  
Ag Particles ◽  
Luminescent Spectra

In this paper, Stöber silica particles were decorated with polyethyleneimine and silver nanoparticles and Eu-polyoxometalates were grafted on the surface of polyethyleneimine/silica spheres. The hybrid SiO2/Eu-polyoxometalates/Ag particles were characterized by IR, UVvis, luminescent spectra, scanning electron microscopy, transmission electron microscope, and cyclic voltammetry (CV), respectively. The hybrid particles show the bright red emission under UV light which can be observed by naked eyes. The luminescent properties of particles have been investigated which show that Ag nanoparticles have an influences on the luminescence of europium ions. The electrochemical activities of SiO2/Eu-polyoxometalates/Ag particles have been demonstrated by CV measurement. The catalytic results indicate that the hybrid particles show the catalytic properties in the oxidation of styrene and benzaldehyde is the main product of the reaction.

Synthesis and luminescent properties investigation of novel red emission phosphors Ca7Zn2(PO4)6: Re3+ (Re =Eu, Sm and Pr)

2019 ◽  
Vol 1181 ◽  
pp. 203-208 ◽  
Author(s):  
Shuangyu Xin ◽  
Faguang Zhou ◽  
Chuang Wang ◽  
Xuejiao Wang ◽  
Zhuowei Li ◽  
...  
Keyword(s):  
Luminescent Properties ◽  
Red Emission

Structure and Up-Conversion Luminescence Properties of Er3+-Yb3+Co-Doped TiO2 Nanocrystals Prepared by Sol-Gel Method

2009 ◽  
Vol 66 ◽  
pp. 167-170 ◽  
Author(s):  
Zhen Zhong Zhang ◽  
Ji Hong Zhang ◽  
Wei Zhou ◽  
Ming Xia Song ◽  
Wei Li ◽  
...  
Keyword(s):  
Titanium Tetrachloride ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Red Emission ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Co Doped

Er3+/Yb3+ co-doped TiO2 nanocrystals were prepared by Sol-gel method in which titanium tetrachloride was adopted as the precursor. The structure, particle size, and optical properties of samples were characterized by X-ray diffraction(XRD), Field emission-Scanning Electron Microscopy(FE-SEM) and photoluminescence(PL) spectra. Er3+ concentration was fixed at 1.0mol%, and Yb3+ concentration was changed from 3 to 10mol%. Intense upconversion luminescence was observed when the samples were excited by 980nm laser. The dependence of upconversion luminescence on Yb3+ concentration was presented. The results show that the upconversion luminescence increases with the Yb3+ concentration and gets its peak at 5%. The ratio of red emission to green emission(R/G) was strikingly enhanced with the increase of Yb3+ concentration. Under the excitation of 980nm, the green emission in the range of 520-570nm (2H11/2, 4S3/2→4I15/2) and the red emission in the range of 640~690nm (4F9/2 →4I15/2) are both due to two photons process. The possible upconversion mechanism was discussed.

scholarly journals Novel Tunable Green-Red Luminescence in Mn2+ Doped Ca9Tb(PO4)7 Phosphors Based on the Mn2+ Regulation and Energy Transfer

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 952
Author(s):  
Bingwen Yang ◽  
Yefeng Feng ◽  
Qinghu Zhao ◽  
Miao He ◽  
Yang Lv
Keyword(s):  
Energy Transfer ◽  
Green Emission ◽  
Energy Transfer Mechanism ◽  
Red Emission ◽  
Broadband Emission ◽  
Characteristic Emission ◽  
Potential Applications ◽  
Light Excitation ◽  
Red Luminescence ◽  
Thermal Stability Of

β-Ca3(PO4)2 type phosphors Ca9Tb(PO4)7:Mn2+ were fabricated by high temperature solid state reaction. Under 377 nm light excitation, the Ca9Tb(PO4)7 host displays the green emission attributable to the characteristic emission of Tb3+ ions peaking at 488, 542, 586, and 620 nm, respectively. The red broadband emission is observed when Ca9Tb(PO4)7 is doped with Mn2+ ions. The emission is attributed to the energy transfer from Tb3+ to Mn2+ ions; this facilitates the realization of the tunable green–red emission. The energy transfer mechanism from Tb3+ to Mn2+ is defined as quadrupole–quadrupole interaction. Furthermore, the thermal stability of Ca9Tb(PO4)7:Mn2+ samples has been studied, and it can maintain half the emission intensity exceeding 424 K. This demonstrates their potential applications in white light LEDs (w-LEDs).

Composition-Dependent Ultraviolet up-Conversion Luminescence in Yb3+-Ho3+ Co-Doped Germanium- Phosphate Glasses

2011 ◽  
Vol 266 ◽  
pp. 5-8 ◽  
Author(s):  
Yan Min Yang ◽  
Wei Zhang ◽  
Shan Du ◽  
Zhi Ping Yang
Keyword(s):  
Emission Intensity ◽  
Glass Sample ◽  
Green Emission ◽  
Phosphate Glasses ◽  
Ultraviolet Emission ◽  
Red Emission ◽  
Excitation Mechanisms ◽  
Uv Visible ◽  
Holmium Ion ◽  
Co Doped

Yb3+-Ho3+ co-doped germanium-phosphate glasses have been prepared and characterized for its optical properties through measuring photoluminescence and Raman spectra. UV-visible up-conversion emission of holmium ion in Yb3+-Ho3+ co-doped germanium-phosphate glasses has been observed on 980nm excitation. As phosphate was substituted for germanium the red emission Red I decreased at first and then increased later while the green emission Green I decreased and the ratio of Red I to Green I increased. Interestingly, the value of ultraviolet emission intensity was larger than that of the blue and green emission intensity in phosphate glass sample. We believe that Yb3+-Ho3+ co-doped germanium-phosphate glasses might be a potential host material for developing ultraviolet all–solid compact lasers. The possible excitation mechanisms involved in these emissions were discussed, too.

Synthesis, Characterization, and Luminescent Properties of a Red-Emitting Europium Complex

2012 ◽  
Vol 512-515 ◽  
pp. 1771-1775
Author(s):  
Li Ying Zhang ◽  
Bin Li ◽  
Gang Lv
Keyword(s):  
Photophysical Properties ◽  
Luminescent Properties ◽  
Europium Complex ◽  
Maximum Efficiency ◽  
Red Emission ◽  
Phenanthroline Ligand ◽  
Organic Devices ◽  
20 Nm

a fluorine functionalized 1,10-phenanthroline ligand, 3-ethyl-2-(2-fluorophenyl) imidazo[4,5-f]1,10-phenanthroline(EFPIP) and the corresponding red-emitting Eu(ΙΙΙ) complex Eu(DBM)3(EFPIP) (DBM = dibenzoylmethanate) was synthesized and the photophysical properties and electroluminescent(EL) performances were researched. When Eu(DBM)3(EFPIP) was used as emitting material in organic devices, the maximum efficiency and luminance of red emission achieved from the EL device with the configuration of ITO/m-MTDATA (30 nm)/NPB (20 nm)/ x wt% Eu(DBM)3(EFPIP) doped in CBP (30 nm)/Bphen (20 nm)/Alq3 (20 nm)/LiF (0.8 nm)/Al were 3.6 cd/A and 563 cd/m2, respectively. Compared with the previously reported devices based on methyl or chlorine substitute Eu(ΙΙΙ) complexes, the EL performances of the device using Eu(DBM)3(EFPIP) as an emitter was significantly enhanced due to the introduction of fluorine.

Synthesis of Nano-Sized Oxide Phosphor Particles Using an Ion-Exchange Polymer/Water/Oil Emulsion Method

2009 ◽  
Vol 421-422 ◽  
pp. 494-498
Author(s):  
Hiroyuki Sano ◽  
Seiichiro Harada ◽  
Mikio Shimizu ◽  
Makoto Kuwabara
Keyword(s):  
Ion Exchange ◽  
Carboxymethyl Cellulose ◽  
Solid Phase ◽  
Luminescent Properties ◽  
Chemical Solution ◽  
Phosphor Powder ◽  
Mechanical Grinding ◽  
Red Emission ◽  
Oil Emulsion ◽  
Emulsion Method

We synthesized nano-sized Eu-doped Y2O3 (Y2O3:Eu) phosphor powder by an ion-exchange po-lymer/water/oil (W/O) emulsion method using carboxymethyl cellulose (CMC) as the ion-exchange polymer, in which the CMC-(Y, Eu) gel formed was calcined at 800°C in air to convert into Y2O3:Eu particles. The obtained phosphor powder consists of unagglomerated particles with sizes in the range of 30-80 nm and exhibits strong red emission at 612 nm. This CMC/W/O method for producing nano-sized oxide powder has significant advantages over conventional solid-phase and chemical solution-based methods because this method can provide unagglomerated nanoparticles of oxide phosphor without employing any mechanical pulverizing process for reducing the particles’ size into the nanometer range; mechanical grinding, such as ball milling, of phosphor powders has been well known to cause a significant degradation of their luminescent properties.

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