Effect Of Tm3 Research Articles

Preparation of the up-conversion glass-ceramics and its synergistic effect on the photocatalytic degradation of photocatalyst

The B2O3–CaF2–Bi2O3 glass-ceramics precipitating CaF2 crystal were prepared by high temperature melting method. The effects of heat treatment schedules, B2O3: Bi2O3 ratio on crystallization behavior and microstructure of base glass were studied. Up-conversion glass-ceramics with Yb3+ as sensitizer and Tm3+ as activator were also prepared, and the effects of Tm3+ doping on their crystallization, microstructure, and up-conversion luminescence performance were analyzed through DSC, XRD, SEM, TEM and PL. To improve further the up-conversion luminescence peformance, Li+ doped up-conversion glass-ceramics and the effect of Li+ doping amount were prepared and explored. The results indicated that the up-conversion luminescence intensity reached its highest when the doping concentrations of Yb3+, Tm3+ and Li + ions were 10 mol%, 0.1 mol% and 6 mol%, respectively. To explore the effect of the prepared up-conversion glass-ceramics on the photocatalytic degradation of ZnIn2S4–Ag–LaFeO3 photocatalyst to dye contaminated model methylene blue (MB), the photocatalytic degradation experiment was carried out by mechanical mixing of up-conversion glass-ceramics and photocatalyst. It was found that the addition of up-conversion glass-ceramics increased the photocatalytic degradation efficiency by 25% under near-infrared light and 7.3% under full spectrum.

Up-conversion luminescence properties and temperature sensing behavior of Nd3+/Yb3+/Tm3+ triply doped LaNbO4 phosphors under 808 nm and 980 nm excitations

LaNbO4: Nd3+/Yb3+/Tm3+ phosphors were synthesized via a solid-state reaction method. Under both 808 nm and 980 nm excitations, the effects of Tm3+ concentration and temperature on the up-conversion luminescence properties of Tm3+ were investigated. From the excitation power densities dependent up-conversion emission intensities, it was confirmed that the up-conversion luminescence process of Tm3+ was insensitive to sample temperature within the temperature range we studied. Under the excitations of 808 nm and 980 nm, both blue and red up-conversion emissions of Tm3+ kept two-photon and three-photon processes at various temperatures. And the near-infrared (NIR) up-conversion emission of Tm3+ was two-photon process when excited at 980 nm. Variation of the fluorescence intensity ratio (FIR) based upon the two thermally coupled energy levels 3F2,3 and 3H4 of Tm3+ with temperature was investigated and the temperature sensing behavior of Tm3+ was studied under 980 nm excitation. In the temperature range from room temperature to 663 K, the absolute temperature sensitivity of Tm3+ increases monotonously with the elevation of temperature, and the maximum value was obtained to be 3.702 × 10-4 K-1 at 663 K.

Quantum cutting in Tm3+-activated Ca9Gd(PO4)7 phosphors and effect of Tm3+ concentration on emission spectra

In this work, to develop new quantum cutting (QC) luminescent materials and clarify the QC process, a series of Tm3+-activated Ca9Gd(PO4)7 (CGP) phosphors were prepared by conventional high-temperature solid state reaction method. The phase purity of the samples was checked by XRD patterns, and the structural features were analyzed on the basis of Rietveld refinement. The emission spectra of Tm3+ were measured by exciting at different wavelengths, in which the QC was identified. The main QC model was proposed when the Tm3+ is excited into 1D2 level. The occurrence of QC was further verified by comparing the decay lifetimes on 3H4 level under 357, 470 and 685 nm excitation. With increasing Tm3+ concentration, it was found that the 3H4→3H6 transition intensity around 806 nm exhibits faster increase rate than other ones by exciting at either 357 or 470 nm. This increase rate is more effective under 357 nm excitation thanks to the existence of QC process. The above investigation could show instructional significance for the development of other rare earth ions doped luminescent materials.

Effect of Tm3+ concentration on structure, defect, and spectral properties of Tm: YAP crystals

Effect of Tm3+ concentration on structure, defect, and spectral properties of Tm: YAP crystals

The influence of Tm3+ to enhance 2.7 μm mid-infrared emission of Er3+ in CaLaGa3O7 crystal

Er3+/Tm3+:CaLaGa3O7 (abbr. as Er3+/Tm3+:CLGO) crystal was grown successfully by Czochralski technology and detailed spectroscopic analyses were carried out. The effects of Tm3+ on the spectroscopic properties and mutual energy transfer mechanisms were investigated. It is found that the more suitable pumping scheme for laser applications at 2.7 μm laser is 980 nm excitation for Er3+/Tm3+ co-doped CLGO crystal. Under 980 nm excitation, the introductions of Tm3+ are helpful to achieve enhanced mid-infrared (MIR) emissions, as well as reduced near-infrared emissions. Furthermore, the introducing Tm3+ depopulated the lower laser lever through energy transfer and thus reduced the fluorescence lifetime of Er3+ : 4I13/2, without significantly affecting the fluorescence lifetime of the upper laser level Er3+ : 4I11/2, which reduces the self-saturation problem to a great degree. It concludes that this Er3+/Tm3+:CLGO crystal could be a potential MIR gain media for enhanced 2.7 μm laser under 980 nm pumping.

Effect of Tm3+ Concentration on the Generation of Reactive Oxygen Species in NaYb1 – xF4:$${\text{Tm}}_{x}^{{3 + }}$$ for the Multifunctional Photosensitizer

To develop the multifunctional photosensitizer NaYb1 – xF4:$${\text{Tm}}_{x}^{{3 + }}$$, the effect of Tm3+ concentration on the photosensitivity in NaYb1 – xF4:$${\text{Tm}}_{x}^{{3 + }}$$ nanoparticles (NPs) was investigated. Photosensitivity in NaYb1 – xF4:$${\text{Tm}}_{x}^{{3 + }}$$ was characterized by chemical probe method, in which 1,3-diphenylisobenzofuran (DPBF) was used as the indicator; and DPBF consumption rate (k) can be used to evaluate the photosensitivity. Experimental results show that in the concentration range of 0–2% for Tm3+, k decreases linearly with increase in Tm3+ concentration with the slope of 0.3. This is mainly attributed to the introduction of fluorescence channel from Yb3+ to Tm3+, which weakens the energy transfer from Yb3+ to oxygen, decreasing k. The result is also confirmed in theoretical analysis.

High hardnesses of Tm3+-doped La2O3-Al2O3 luminescent glasses fabricated by containerless solidification

A series of colorless and transparent (28-x)La2O3-72Al2O3:xTm3+ (x = 0, 1, 1.5, 2, 3) luminescent glasses were successfully prepared by the containerless method. The effects of Tm3+ substitution on the physical, thermal, optical and photoluminescence properties of La2O3-Al2O3 glasses were investigated. X-ray diffraction confirmed the amorphous natures of the as-prepared glasses. Excitated at 354 nm, La2O3-Al2O3:Tm3+ glasses emitted blue luminescence at 457 nm, corresponding to the 1D2→3F4 transition of Tm3+. These glasses showed high Vicker's hardnesses (7.2–8.8 GPa), and excellent thermal stabilities (Tg: 840–851 °C), which were both augmented with increasing content of Tm3+. They also exhibited high transmittances in a wide window ranging from 220 nm to 8.9 μm. In conclusion, the substitution of Tm2O3 for La2O3 increased the Vicker's hardness, thermal stability and transmittance window of La2O3-Al2O3 glasses, allowing potential applications to optical devices in the visible to infrared region.

Novel Tm3+ and Yb3+ co-doped bismuth tungstate up-conversion photocatalyst with greatly improved photocatalytic properties

Tm3+ and Yb3+ co-doped Bi2WO6 up-conversion photocatalysts (Tm3+/Yb3+:Bi2WO6) were synthesized via co-precipitation route at different calcination temperatures. Doping Tm3+ and Yb3+ into Bi2WO6 lattice and substituting for the fractional Bi3+ were successfully confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The morphology and optical property of the obtained samples were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS) and up-conversion luminescence spectra (UC-PL). The photocatalytic results revealed that the Tm3+/Yb3+:Bi2WO6 exhibited a much superior photocatalytic activity than the pure Bi2WO6 and commercial Degussa P25 for the degradation of rhodamine B (RhB), and the degradation rate reached 97.6% in 25 min. The effects of Tm3+ and Yb3+ on the photocatalytic activity of Bi2WO6 were studied in detail. The improved photocatalytic activity of Bi2WO6 could be attributed to the efficient energy transfer between Tm3+/Yb3+ and Bi2WO6 via infrared to visible up-conversion and the reduced recombination rate of photogenerated electron-hole pairs through co-doping of Tm3+/Yb3+ on Bi2WO6 nanopaticles.

Structural, optical and magnetic properties of Tm3+ substituted cobalt spinel ferrites synthesized via sonochemical approach

Co-Tm nano-spinel ferrite with chemical formula CoTmxFe2−xO4 (0.0 ≤ x ≤ 0.08) NPs were prepared via sonochemical approach. X-ray powder diffraction patterns, microscopic images (SEM and TEM) and infrared spectra proved the formation of Co spinel ferrite. The effect of Tm3+ substituted on spinal structure was evaluated by lattice parameters, tetrahedral and octahedral bond length and cationic distribution. The band gap energy (Eg) of samples were estimated by performing UV–Vis percent diffuse reflectance (% DR) and applying the Kubelka-Munk theory. Eg values are in an interval between 1.33 eV and 1.64 eV. The analyses of magnetization were performed at room (300 K; RT) and low (10 K) temperatures. Different magnetic parameters including coercivity Hc, saturation magnetization Ms, remanence Mr, squareness ratio (SQR = Mr/Ms) and magnetic moment nB were deduced and discussed. The results showed superparamagnetic (SPM) nature at RT for x = 0.00 and 0.02 samples. However, the other products exhibit ferromagnetic (FM) nature. At 10 K, all synthesized NPs display FM behavior. An amazing increase in the magnitudes of Ms, Mr and Hc was observed at 10 K in comparison to RT, which is principally due to the reduced thermal fluctuations of magnetic moments at lower temperatures. The Tm3+ substitution affects considerably the magnetizations data. An enhancement in the Ms, Mr, and nB was detected on increasing the Tm3+ concentration. The SQR values at RT are found to be smaller than 0.5 postulating a single domain nature with uniaxial anisotropy for all produced ferrites. However, SQRs are in the range 0.66–0.76 at 10 K, suggesting the multi magnetic domain at low temperature, except the x = 0.02 product where the SQR = 0.47 indicating the single magnetic domain. The obtained magnetic results were investigated deeply with relation to structural and microstructural properties.

Electric and optical properties of Tm3+/Yb3+co-doped PZN–9PT crystals

Tm3+/Yb3+co-doped Pb(Zn1/3Nb2/3)O3–9PbTiO3 (PZN–9PT) single crystals were grown by high-temperature flux technique. The effects of Tm3+/Yb3+ ions doping on phase structure, dielectric, ferroelectric and UC luminescence properties were investigated. The XRD, Raman spectrum and TEM results reveal that the Tm3+/Yb3+ ions can diffuse into the lattice of the PZN–9PT and increase the lattice constants. The Curie temperature Tc increases from 170 °C for pure PZN–9PT to 182.5 °C for PZN–9PT: Tm3+/Yb3+. Meanwhile, the coercive field Ec of Tm3+/Yb3+ co-doped PZN–9PT reaches to 12.1 kV/cm which is nearly four times higher than that of PZN–9PT crystal. Under a 980 nm laser excitation, crystals modified by the Tm3+/Yb3+ produce UC with three colors: blue (480 nm, 1G4 → 3H6), strong near-infrared (NIR, 804 nm, 3H4 → 3H6) and weak red (652 nm, 1G4 → 3F4). Our results can provide a new way for the design of multifunctional materials used in optical-electrical devices.

Effect of Tm3+ concentration on the emission wavelength shift in Tm3+-doped silica microsphere lasers.

In this work, a Tm3+-doped solgel silica microsphere lasing at 2.0μm is reported. Microspheres with different Tm3+ concentrations are fabricated by overlaying different Tm3+ concentration solgel solutions on the surface of a pure silica microsphere resonator and then annealing the sample with a CO2 laser. Based on a traditional fiber taper-microsphere coupling method, single and multimode microsphere lasing in the wavelength range 1.8-2.0μm is observed if an 808nm laser diode is used as a pump source. A relatively low threshold pumping power of 1.2mW is achieved using this arrangement. This solgel method allows for an easy varying of the Tm3+ doping concentration. The observed laser output shifts to longer wavelengths when the Tm3+ doping concentration increases. This has been explained by the larger Tm absorption at shorter wavelengths. The ability to fabricate solgel co-doped silica glass microlasers represents a new generation of low threshold and compact infrared laser sources for use as miniaturized photonic components for a wide range of applications, including gas sensing and medical surgery.

Effects of Tm3+ concentration on upconversion luminescence and temperature-sensing behavior in Tm3+/Yb3+:Y2O3 nanocrystals.

The effects of Tm3+ concentration on upconversion emission and temperature-sensing behavior of Tm3+/Yb3+:Y2O3 nanocrystals were investigated. Blue and red emissions were observed under 980nm excitation. Both upconversion emissions and the blue to red intensity ratio were found to decrease with increasing Tm3+ concentration. The temperature-sensing performances of the samples were studied, the fluorescence intensity ratio of 1G4(a)→3H6 (477nm) and 1G4(b)→3H6 (490nm) transitions from Tm3+ ions was chosen as the thermometric index. The results showed that the sensor sensitivity was sensitive to Tm3+ ion concentration. The maximum sensitivity of ~32×10-4K-1 was obtained for 0.1%Tm3+/5%Yb3+:Y2O3 nanocrystals at 344K. Moreover, a marked optical induced heating effect was also found in the nanocrystals. The prepared Tm3+/Yb3+:Y2O3 nanocrystals could be used in temperature-sensing probes and in optical heaters.

The preparation of Yttrium Aluminosilicate (YAS) Glass Fiber with heavy doping of Tm3+ from Polycrystalline YAG ceramics

AbstractYttrium aluminosilicate (YAS) glass core fibers with different doping concentration of Tm3+ were fabricated by a “Melt‐in‐Tube” method from YAG polycrystalline ceramics. The effect of Tm3+ concentration on the spectroscopy of YAG ceramics and laser performance of YAS fibers were discussed. A homemade linear all‐fiber laser based on the obtained 15% Tm3+‐doped YAS fiber shows an optimized slope efficiency of 12.8%. The YAS fibers have been proven to be practical to achieve extremely high Tm3+ doping concentration and are a promising option for the 2.0 μm laser.

TL/OSL properties of beta irradiated Al2O3:Tm3+ phosphor synthesized by microwave combustion method

This work discusses synthesis of stable α-phase of Al2O3:Tm3+ by combustion method using temperature controlled microwave oven. The crystalline phase was analyzed by X-ray diffraction (XRD) technique and average crystallite size was found to be 147 nm. Observations using scanning electron microscope (SEM) image suggest formation of agglomerated particles and energy dispersive x-ray spectroscopy (EDS) confirmed the incorporation of Tm3+ in Al2O3. Thermoluminescence emission (TLE) spectrum of γ – irradiated Al2O3:Tm3+ shows characteristic emissions of Tm3+, Cr3+ and Mn4+. TL glow curves of γ – irradiated Al2O3:Tm3+ exhibit a prominent peak at 453 K along with a shoulder at 496 K. The glow curves of β – irradiated Al2O3:Tm3+ were studied in different emission regions using U340 + BG39 (UV band pass), CS759 + BG39 (Blue band pass) and BG39 (Visible band pass) optical glass filters. A prominent peak was observed at 471 K in for all mentioned emission regions and an additional shoulder was observed at 511 K with CS759 + BG39 and BG39 filters. TL glow curve of β – irradiated Al2O3:Tm3+ using only BG39 filter had more counts than CS759 + BG39 and U340 + BG39 filters. Further, the effect of Tm3+ impurity on TL response was studied. TL kinetic parameters were estimated by using computerized glow curve deconvolution (CGCD) technique. The activation energy and frequency factor of prominent peak (471 K) were found to be 1.31 eV and 3.50 × 1013 s−1 respectively. Optically stimulated luminescence (OSL) characteristics of β – irradiated Al2O3:Tm3+ were studied using U340 + BG39 and CS759 + BG39 filters. Highest OSL intensity was observed in UV. OSL curves were deconvoluted by general order decay equation. Life time and photoionization cross section of the traps responsible for OSL were found to be 5.30 s and 3.98 × 10−18 cm2 respectively. The process of ionization of electron from Tm3+, electron trap in host lattice and its recombination mechanism is proposed. Phosphorescence decay of beta irradiated sample was also studied. The lifetime of phosphorescence decay was found to be 140 s for the prominent peak and TL intensity decays 25% after the phosphorescence. TL/OSL dosimetric properties viz. linearity with dose, reusability and minimum detectable dose of the phosphor were characterized for medical dosimetry application.

Nearly pure NIR to NIR upconversion luminescence in Tm3+, Yb3+ co-doped ZnO-TiO2 composite phosphor powder

Tm3+ and Yb3+ co-doped ZnO-TiO2 composite system were successfully synthesized via powder-solution mixing method and their upconversion (UC) luminescence characteristics were studied as a function of various ZnO/TiO2 mixing ratios and dopant concentrations under 980 nm laser excitation. The XRD patterns showed that the product fired at 1300 °C consisted of four phases, Zn2TiO4, TiO2, RE2Ti2O7, and RE2TiO5 (RE = Tm3+ and/or Yb3+). The NIR emission centered at 795 nm wavelength was detected as the strongest emission intensity which it was in accordance with the 3H4 → 3H6 transition of Tm3+ ion. The NIR emission intensity of the products was varied by changing ZnO-TiO2 mixing ratios, and Tm3+ and Yb3+ concentrations. The simple chemical formula equations, for interpreting the site preference of Tm3+ and Yb3+ ions in the host crystal matrix, were originated by considering the host crystal structure, its crystal arrangement, and the effect of Tm3+ and Yb3+ ions to the changes in lattice parameters of host crystal. The 1ZnO:1TiO2 (in mole) doped with 0.125 mol% Tm3+, 15 mol% Yb3+ fired at 1300 °C for 1 h was the best condition that displayed highest NIR emission intensity. The possible UC mechanism was suggested and discussed in detail.

Luminescence and energy transfer phenomena in Gd3 (Al,Ga)5O12 crystals single doped with thulium and co-doped with thulium and holmium

Single crystals of Gd3Al2.5Ga2.5O12 (GAGG) doped with Tm3+ ions and co-doped with Ho3+ and Tm3+ ions were grown by the Czochralski technique and investigated employing methods of optical spectroscopy. The room temperature absorption spectra of GAGG:Tm3+ were analysed in the framework of the Judd-Ofelt theory. Obtained phenomenological parameters Ω2 = 0.62 × 10−20cm2, Ω4 = 1.41 × 10−20cm2 and Ω6 = 0.80 × 10−20cm2 were used to determine rates of radiative transitions, branching ratio values and radiative lifetimes for excited multiples of incorporated Tm3+ ions. Effect of Tm3+ concentration on decay curves of Tm3+ luminescence was examined and spectroscopic parameters characterizing the donor-acceptor interaction responsible for self-quenching of the emission from the 1D2, 1G4 and 3H4 multiplets were evaluated applying the Inokuti-Hirayama model. The crystal field splitting of Tm3+ multiplets were determined based on low temperature absorption and emission spectra. The emission cross section for Tm3+: 3F4 → 3H6 luminescence was determined to be 0.31 × 10−20cm2 at maximum and corresponding experimental lifetime amounts to 4.3ms resulting in quantum efficiency η = 0.79. The calculated ratio of Tm-Ho to back-transfer processes (CTm-Ho/CHo-Tm) is 5.18.

Near-infrared luminescence of Tm3+-doped CeO2 films based on silicon substrates

CeO2/Tm2O3 multilayer films were deposited on silicon substrates by electron-beam evaporation. Tm3+ ions were doped in CeO2 after the films were annealed in oxygen atmosphere at 1000 °C. The doping concentration of Tm3+ varies in the range of 0.1–3 mol%. A series of near-infrared emission peaks were observed under the excitation of 330 nm, which correspond to 1G4–3H5, 3H4–3H6, 1G4–3H4, 3H5–3H6, 3F2–3H5, 3H4–3F4, 1G4–3F3,2 and 3F4–3H6 transitions of Tm3+, respectively. The dominant transition of 3H4–3H6 near 805 nm was within optical transmission window. The luminescence properties and the crystal structure of CeO2:Tm3+ films were investigated by excitation and emission spectroscopy and X-ray diffraction. Meanwhile, the substitution process of Ce4+ by Tm3+ was illustrated, and lattice expansion of the matrix CeO2 gave rise to the increase in FWHM of CeO2 diffraction peaks. In addition, the effect of Tm3+ concentration on photoluminescence was also studied, and the optimal concentration of Tm3+ was 0.5 mol%.

Study on structure and electrochemical performance of Tm3+-doped monoclinic Li3V2(PO4)3/C cathode material for lithium-ion batteries

Monoclinic Li3V2-xTmx(PO4)3/C with different Tm3+-doping contents (x=0, 0.01, 0.03, 0.05) have been successfully synthesized for the first time via a conventional solid-state reaction. The effect of Tm3+-doping on the crystalline structure, morphology and electrochemical performance of Li3V2(PO4)3/C has been investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical measurements. The same phase-pure monoclinic structure of Tm3+-doped Li3V2(PO4)3/C sample can be obtained from XRD results while the particle size is smaller than that of pristine Li3V2(PO4)3/C. The Li3V1.97Tm0.03(PO4)3/C composite exhibits the most excellent electrochemical performance among all the samples. In the voltage range of 3.0–4.8V, the Li3V1.97Tm0.03(PO4)3/C sample delivers a very high initial discharge capacity of 181.2mAhg−1 at 0.1C, significantly higher than that of pristine Li3V2(PO4)3/C (170.1mAhg−1). Moreover, it can still deliver a discharge capacity of 141mAhg−1 and 123.3mAhg−1 at 5.0 and 10.0C, respectively, and sustain 95.2% and 93.4% of capacity retention after 20 cycles. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results demonstrate that the reversibility of pristine Li3V2(PO4)3/C is enhanced and the charge-transfer resistance is reduced after Tm3+-doping at V sites. These improved electrochemical performance can be contributed to the appropriate addition of Tm3+-doping in Li3V2(PO4)3/C system by enhancing structural stability and electrical conductivity.

Effect of Tm3+ codoping on the near-infrared and upconversion emissions of Er3+ in TeO2–ZnO–ZnF2 glasses

In this work, we report the near-infrared emission and upconversion of Er3+–Tm3+ codoped fluorotellurite TeO2–ZnO–ZnF2 glasses for different Tm3+ concentrations by using steady-state and time-resolved spectroscopy. A broad emission from 1350 to 1700nm corresponding to the 3H4→3F4 (Tm3+) and 4I13/2→4I15/2 (Er3+) emissions which cover the complete telecommunication window of the wavelength-division-multiplexing transmission systems is observed. The full width at half-maximum of this broadband increases with increasing Tm3+/Er3+ concentration ratio up to a value of~150nm. Energy transfer between Er3+ and Tm3+ ions is also observed and analyzed by both the temporal behavior of the near-infrared luminescence and the effect of Tm3+ codoping on the visible upconversion of Er3+ ions. The addition of Tm3+ reduces the upconverted green emission due to Er3+→Tm3+ energy transfer whereas the red emission is enhanced due to the cross-relaxation 3F4→3H6(Tm3+):4I11/2→4F9/2(Er3+) process.

Effect of Tm3+ Sensitization to Ho3+ Doped GeO2-B2O3-BaF2-Al2O3-ZnO2-Na2O Glass on Spectral Properties

Effect of Tm3+ Sensitization to Ho3+ Doped GeO2-B2O3-BaF2-Al2O3-ZnO2-Na2O Glass on Spectral Properties