scholarly journals Effects of Li+ Doping Concentration on Structure and Photoluminescence of the Y2O3: Ho3+/Yb3+ Up-conversion Film

2019 ◽  
pp. 1-8 ◽  
Author(s):  
Min Sun ◽  
Wenbo Hou ◽  
Juncheng Liu ◽  
Lifang Nie
Keyword(s):  
Doping Concentration ◽  
Crystal Size ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Optical Transmittance ◽  
Li Doping ◽  
Maximum Value ◽  
Size Of Particles ◽  
Co Doped

The Li+ co-doped Y2O3: Ho3+/Yb3+ films were prepared with sol-gel method and spin-coating technique. The effects of Li+ on the structure and luminescent properties of the films were investigated. The results show the grain size increased first and then decreased with the increase of Li+ doping concentration. The crystal size of particles composing the film got the maximum value when Li+ concentration took 4 mol%. As Li+ doping concentration increased, the optical transmittance of the Y2O3: Ho3+/Yb3+ film improved at first then reduced and got the maximum at 3 mol%. Excited with a 980-nm laser, there were two green emissions in the up-conversion emission spectra, one centered at 535 nm, the other at 550 nm, which ascribed to the 5F4→5I8 and 5S2→5I8 transitions of Ho3+, respectively. The up-conversion luminescence intensity also increased firstly and then decreased with the Li+ doping concentration increase, and got the highest value at 2 mol%.

scholarly journals PENGARUH PENAMBAHAN CO-DOPING Mg/La TERHADAP KARAKTERISASI TiO2 SEBAGAI FOTOELEKTRODA

2021 ◽  
Vol 9 (1) ◽  
pp. 79-86
Author(s):  
Mursal Mursal ◽  
◽  
Nurul Azmi ◽  
Ismail Ismail ◽  
◽  
...  
Keyword(s):  
Doping Concentration ◽  
Crystal Size ◽  
Energy Gap ◽  
Dopant Concentration ◽  
Sol Gel ◽  
Pure Tio2 ◽  
Tio2 Sample ◽  
Doped Tio2 ◽  
Co Doping ◽  
Co Doped

The effect of Mg/La co-doping addition on the caracteristics of TiO2 as photoelectrode have been studied. This study aims to investigate the effect of Mg/La co-doping concentration on the characteristics of TiO2. This study aims investigate the effect of Mg/La co-doping concentration on the characteristics of TiO2. Mg/La was varied from 0% mol, 0.4 / 0.6% mol, and 0.6 / 0.4% mol. Synthesis of TiO2 co-doping Mg/La was done by sol gel method. The resulting of powder pure TiO2 and co-doping Mg/La was made to paste, and was deposited on a glass substrate with a size of 2.5 x 2.5 cm and sintered at 600°C for 1 hour. Mg / La co-doped TiO2 layers were characterized using XRD, UV-Vis, and FTIR spectrometers. The results showed that TiO2 was the mos dominan phase appeared in pure TiO2 sample. The phase of MgO, MgTiO3, Mg2TiO4, and La2O3 were found in Mg/La co-doped TiO2 samples. The crystal size of Mg/La co-doped TiO2 was varied from 8.85 to 7.70 nm. In this research, we obtained that the energy gap was varied from 3.52 to 3.5 eV depent on co-dopant concentration. FTIR measurement showed groups of Ti-O, Ti-O-Ti, Ti-O-O, and H-O.

scholarly journals The Effects of Li+ Doping on Structure and Upconversion Luminescent Properties for Bi3.46Ho0.04Yb0.5Ti3O12: xLi Phosphors

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1220
Author(s):  
Feng Ren ◽  
Jinlei Zhou ◽  
Dengpeng Wang ◽  
Xianran Wang ◽  
Feng Gao
Keyword(s):  
Upconversion Luminescence ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Xrd Analysis ◽  
Upconversion Emission ◽  
Li Doping ◽  
Energy Transfers ◽  
Photon Process ◽  
Sintering Method

A series of novel Li+ doped Bi3.46Ho0.04Yb0.5Ti3O12 (BHYTO: xLi, 0 ≤ x ≤ 0.15) upconversion phosphors were prepared through a sol-gel-sintering method. There exist three emission bands centered at 545 nm, 658 nm, and 756 nm in the upconversion emission spectra at 980 nm excitation, corresponding to energy transitions of 5F4/5S2 → 5I8, 5F5 → 5I8 and 5F4/5S2 → 5I7 of Ho3+, and the upconversion emission intensity of BHYTO: 0.05Li is about 2.2 times stronger than that of BHYTO samples. The luminescent lifetime of the strongest emission (545 nm) is in the range of 45.25 to 65.99 μs for the different BHYTO: xLi phosphors. The energy transfers during the upconversion pumping process from Yb3+ to Ho3+ are mainly responsible for all the emissions, each belonging to a double-photon process. Li+ mainly entered into the interspace sites or occupied Bi3+ sites in Bi4Ti3O12 host during the fabrication process according to its dosage, and the possibility is very low for Li+ to take part in the energy transfer process directly due to its lack of matching levels with 4f of Ho3+ and Yb3+. However, Li+ doping can not only increase the size of crystal grains to improve crystallinity through XRD analysis, but also reduced oxygen vacancies to decrease the number of quenching centers through XPS analysis. The improved crystallinity and reduced quenching centers are proposed to be the main causes for the enhanced upconversion luminescence of the Li+ doped BHYTO phosphor.

scholarly journals Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 937
Author(s):  
Katarzyna Halubek-Gluchowska ◽  
Damian Szymański ◽  
Thi Ngoc Lam Tran ◽  
Maurizio Ferrari ◽  
Anna Lukowiak
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Emission Spectra ◽  
Transmission Electron ◽  
Characteristic Emission ◽  
Diffraction Patterns ◽  
Size Of Particles ◽  
Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing

2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Organic Additive ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Close Relationship ◽  
Dip Coating Technique

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.

scholarly journals Upconversion Luminescence and Photodegradation Performances of Pr Doped Y2SiO5Nanomaterials

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yi Yang ◽  
Cheng Liu ◽  
Ping Mao ◽  
Lian-Jun Wang
Keyword(s):  
Doping Concentration ◽  
Crystal Size ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Fine Crystal ◽  
X Ray ◽  
Photodegradation Rate ◽  
Infrared Spectrometer ◽  
Fluorescence Spectrometer ◽  
Degradation Time

Yttrium silicates Y2SiO5upconversion nanomaterials with different doping concentrations of praseodymium ion Pr are prepared by using a sol-gel method. X-ray diffractometer, SEM, Fourier transform infrared spectrometer, and fluorescence spectrometer have been employed to test the crystal structure and upconversion luminescence performances. The results indicate that samples calcined higher than 950°C present fine crystal structures, of which Si-O-Si band at 757–1048 cm−1splits into three fine peaks. The crystal size of the samples calcined at 950°C and 1000°C is 29.1 nm and 66.7 nm, respectively. The luminescence intensities of the samples are increasing at first and then decreasing, with the increasing of the doping concentrations of 0.47%, 0.77%, 0.96%, 2.95%, and 4.93%. Nanomaterial sample doped 0.96% Pr emits the highest upconversion luminescence intensity of 6.43 × 106 cps and shows the best photodegradation performance for nitrobenzene wastewater. It demonstrates that too much of Pr doping concentration would result in quenching of the fluorescence. Nevertheless, as the degradation time expands, sample doped 0.96% Pr shows much faster increasing of photodegradation rate than samples of other doping concentrations and reaches to a high photodegradation rate of 97.14% in 6 hours for 10 mg/L nitrobenzene wastewater.

Synthesis and Luminescent Properties of Mn2+-Doped Zinc Silicate Phosphors by Sol-Gel Method

2010 ◽  
Vol 434-435 ◽  
pp. 214-216 ◽  
Author(s):  
Ji Ming Zhang ◽  
Dong Lin Zhao ◽  
Zeng Min Shen
Keyword(s):  
Sol Gel ◽  
Green Light ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Nano Particles ◽  
Light Emitting ◽  
Gel Method ◽  
Sol Gel Method ◽  
Structural Details ◽  
Xrd Patterns

Abstract. Green light emitting Mn2+-doped Zn2SiO4 (Zn2SiO4:Mn2+) phosphor nano-particles were synthesized by sol-gel method combined with a furnace firing from the sol-gel solution made with ZnO, MnCO3 and tetraethoxysilan. The influences of annealing temperatures on the microstructures and photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were investigated. The structural details of the phosphors were examined through XRD and SEM. The photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were characterized by excitation and emission spectra. The results indicate that the XRD patterns of the Zn2SiO4:Mn2+ phosphors exhibit a willemite structure (-Zn2SiO4). Green photoluminescence whose emission peak is located at 525 nm were observed from the synthesized phosphor particles under UV excitation. The photoluminescent mechanisms of the Zn2SiO4:Mn2+ phosphors were discussed.

Luminescent Properties of ZnxCa1–xTiO3:yPr3+ Long-Lasting Phosphors

2016 ◽  
Vol 35 (9) ◽  
pp. 963-966
Author(s):  
Yanzhi Meng ◽  
Xiaomin Wang ◽  
Yi Shen ◽  
Xiaoli Wei ◽  
Liying Han ◽  
...  
Keyword(s):  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Concentration Quenching ◽  
Molar Concentration ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Quenching Effect ◽  
Concentration Quenching Effect

AbstractThe red long-lasting phosphors (LLPs) ZnxCa1–xTiO3:yPr3+ (ZCTP) were successfully prepared via the sol–gel method. The effects of Zn2+ content and Pr3+ molar concentration on the luminescent properties of ZCTP LLPs were characterized by X-ray diffraction, excitation and emission spectra, long-lasting decay curves and thermoluminescence (TL) curves. In this study, the results indicated that luminescent properties of Zn0.2Ca0.8TiO3:0.2 %Pr3+ phosphor was the best. In addition, when Pr3+ molar concentration reached 0.8 mol %, concentration quenching effect was obvious.

Morphology, structural and luminescent properties of sol-gel synthesized SiO2 powders co-doped with Sr2+ and Tb3+

2020 ◽  
Vol 580 ◽  
pp. 411817
Author(s):  
R.G. Moji ◽  
R.E. Kroon ◽  
S.V. Motloung ◽  
T.E. Motaung ◽  
L.F. Koao
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Co Doped

Ga-Sn Co-Doped ZnO Films via Sol-Gel Route

2018 ◽  
Vol 280 ◽  
pp. 43-49
Author(s):  
Zi Neng Ng ◽  
Kah Yoong Chan
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Band Gap ◽  
Doping Concentration ◽  
Sol Gel ◽  
Zno Films ◽  
Axis Orientation ◽  
Co Doping ◽  
Doped Zno ◽  
Co Doped

Zinc oxide (ZnO) has gained worldwide attention due to its direct wide band gap and large exciton binding energy, which are important properties in the application of emerging optoelectronic devices. By doping ZnO with donor elements, a combination of good n-type conductivity and good transparency in the visible and near UV range can be achieved. Co-doping ZnO with several types of dopants is also beneficial in improving the electronic properties of ZnO films. To the best of our knowledge, the fundamental properties of gallium-tin (Ga-Sn) co-doped ZnO (GSZO) films were rarely explored. In this work, we attempt to coat GSZO films on glass substrates via sol-gel spin-coating method. The Ga-Sn co-doping ratio was fixed at 1:1 and the concentration of the dopants was varied at 0.5, 1.0, 1.5, and 2 at.% with respect to the precursor. The AFM image show granular features on the morphology of all GSZO films. All samples also exhibit a preferential c-axis orientation as detected by XRD. The XRD indicates higher crystal quality and larger crystallite size on GSZO thin films at 2.0 at.% and agrees well with the AFM results. However, the transparency and optical band-gap of the GSZO thin films degrade with higher co-doping concentration. The best electrical properties were achieved at co-doping concentration of 1 at.% with conductivity and carrier density of 7.50 × 10-2S/cm and 1.37 × 1016cm-3, respectively. At 1.0 at.% co-doping concentration, optimal optical transmittance and electrical properties were achieved, making it promising in the application of optoelectronics.

A Novel Phenomenon of Energy Transfer in Cd1-XZnxSiO3 : 0.01 Mn2+ Phosphor

2012 ◽  
Vol 549 ◽  
pp. 487-490 ◽  
Author(s):  
Xin Mu Zhou ◽  
Yong Xiu Li
Keyword(s):  
Energy Transfer ◽  
Ultraviolet Light ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Emission Peak ◽  
Red Shift ◽  
Excitation Spectra ◽  
Gel Method ◽  
Sol Gel Method

Cd1-xZnxSiO3:0.01 Mn2+phosphor was synthesized by sol-gel method. It was characterized by excitation, emission spectra and XRD. The luminescent properties show the phenomenon of energy transfer from the tetrahedral coordinated Mn2+ion to the octahedral coordinated Mn2+ion after exciting by ultraviolet light, which boost the performance of the phosphor. With the increasing of Zn2+in Cd1-xZnxSiO3:0.01 Mn2+phosphor, it was observed the excitation spectra broadened and a red shift in the emission spectra, which emission peak moved from 580nm to 589nm.

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