Emission Of Yb3 Research Articles

Broadened and enhanced MIR emission in Yb3+/Er3+/Dy3+ triply-doped CaYAlO4 crystal

Yb3+/Er3+/Dy3+ triply-doped CaYAlO4 single crystal was successfully grown to obtain the broadened and enhanced 3 μm MIR emission. The structure characters were studied by XRD measurement. The optical properties and energy transfer mechanism between Yb3+, Er3+, and Dy3+ were investigated according to the measured absorption spectra, emission spectra, and fluorescence decay curves. The absorption spectra show that the triply-doped crystal could be effective pumped by 980 nm due to the introduced of Yb3+ and Er3+. In comparison with Dy3+ singly-doped CaYAlO4 crystal, a broadened and enhanced ∼3 μm MIR emission with a full width at half maximum (FWHM) of 286 nm was obtained due to the fact that there exists effective energy transfer process from Yb3+ and Er3+ to Dy3+. For Yb3+, it serves as an effective sensitized ion. For Er3+, it could be not only used as an effective sensitized ion, but also as a 2.7 μm MIR emission center. For Dy3+, it serves as a deactivating ion to solve the self-termination “bottleneck” effect of Er3+, and more importantly, as an emission center to achieve 3 μm emission. The comprehensive effect is to obtain enhanced and broadened MIR emission in the triply-doped crystal. In addition, the corresponding energy transfer efficiency from Yb3+: 2F5/2 to Dy3+: 6H5/2 is as high as 90 %. Hence, the Yb3+/Er3+/Dy3+: CaYAlO4 crystal could be used as promising medium for MIR broadband tunable laser applications.

NIR-driven intense UV upconversion films for non-contact high-efficiency prevention of bacterial infections

Bacterial infections on wounds imposes a significant limitation to the wound healing. Although the conventional drug antibacterial dressing is employed for hindering bacterial infection, the inevitable microbial resistance and secondary damage severely limit the quality and speed of wound healing. Herein, the NIR-driven intense UV upconversion (UC) BaLu2F8:80%Yb3+/0.5%Tm3+ microcrystals are, for the first time, designed and fabricated into solid sterilization film to protect the wounds from infections. Equipped with excessive Yb3+ sensitizers, the emission of Yb3+/Tm3+ co-doped monoclinic BaLu2F8 matrix achieve a 175-fold enhancement at the UV band. The UV UC microcrystals was further fabricated into a NIR-to-UV sterilization film with a diameter of 1.5 cm and a thickness of 150 μm using solution casting method, which can efficiently destroy 97 % of E. coli with a NIR irradiation of 5 minutes. Due to the outstanding penetrability of NIR irradiation, the sterilization film under 4 layers gauze dressing can be activated to produce UV photons. The in-vivo mouse tests demonstrate the well-designed NIR-to-UV sterilization film can speed up the wound healing by high-efficient inhibiting E. coli infection under the irradiation of 980 nm NIR laser. The non-contact NIR-driven UV sterilization film require no more drugs and dressing exchange, thus entirely eliminating the effect of microbial resistance and secondary damage from conventional drug dressing. Our work provides a new alternative for constructing highly-efficiency sterilization dressing through the utilization of NIR-to-UV optical conversion materials.

Evolution of In2O3 nanocrystal and its impact on structure parameters and infrared emission in Yb3+: SiO2/In2O3 ceramic nanopowder

Using the sol-gel method, we have synthesized nanocrystalline Yb3+: SiO2/In2O3 ceramic nanopowder. XRD pattern shows the cubic phase of In2O3 that is perfectly evolved at 300°C. The In2O3 nanoparticles of ∼10–15 nm size were formed, and their W-H plots demonstrated the microstrain owing to the structural imperfections. In FTIR, a fingerprint region was observed near 577 cm−1, corresponding to the In-O bond. SEM images have determined the irregular surface morphology and formation of grain boundaries in prepared ceramic powder. X-ray photoelectron spectroscopy established the 3+ oxidation state of ytterbium and confirmed the oxide phases of SiO2 and In2O3. Absorption bands were observed in UV-Vis spectra at 250, 320, and 895 nm corresponding to the SiO2 host, In2O3 nanoparticles, and dopant ions. To investigate the emission corresponding to Yb3+, the In2O3 consequences were explored on structural parameters and infrared emission of Yb3+: SiO2 where In2O3 acted as the sensitize. The NIR luminescence was efficiently boosted by increasing the In2O3 content. The energy transfer from In2O3 to Yb3+ ions takes place effectively, and thus, UV photons are converted to NIR in the 980–1060 nm region for Si-solar cell substitutes. Moreover, the broad luminescence from UV-to-NIR would be employable in photonic appliances, particularly fiber lasers and 3D displays.

Enhanced upconversion emission in Nd, Yb, Er and Ho tetra-doped Y2O3 phosphor

Yb3+, Nd3+, Er3+ and Ho3+ tetra ions doped Y2O3 upconversion phosphors have been prepared by the combustion route. Crystalline phase purity and cubic phase of prepared samples have been confirmed from powder X-ray diffraction study. Absorbance of samples over spectral range 200–1100 nm has been measured by diffuse reflectance spectroscopy. All samples exhibit large band gaps. Scanning electron micrograph analysis reveals spherical morphology of particles and sizes around 200 nm. Upconversion emission has been studied under a 980 nm diode laser excitation with 166 mW laser power. The Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor show very high emission intensity of a green band centred at around 550 nm and another moderate intensity red band centred on 667 nm, while reverse is the case for Er3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor. Er3+, Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor show enhanced high emission intensity in both green and red bands. These two bands are not visible in Nd3+ and Yb3+ co-doped Y2O3 phosphor but show weak upconversion emission at 549, 568 and 799 nm. Owing to the high emission intensity of green band, Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor may find potential applications in medical and security, while Er3+, Ho3+, Nd3+ and Yb3+ co-doped phosphor showing enhanced upconversion in green and red bands may find applications in white light generation.

Raspberry-like Nanoheterostructures Comprising Glutathione-Capped Gold Nanoclusters Grown on the Lanthanide Nanoparticle Surface.

Bare lanthanide-doped nanoparticles (LnNPs), in particular, NaYF4:Yb3+,Tm3+ NPs (UCTm), have been seeded in situ with gold cations to be used in the subsequent growth of gold nanoclusters (AuNCs) in the presence of glutathione (GSH) to obtain a novel UCTm@AuNC nanoheterostructure (NHS) with a raspberry-like morphology. UCTm@AuNC displays unique optical properties (multiple absorption and emission wavelengths). Specifically, upon 350 nm excitation, it exhibits AuNC photoluminescence (PL) (500-1200 nm, λmax 650 nm) and Yb emission (λmax 980 nm); this is the first example of Yb sensitization in a UCTm@AuNC NHS. Moreover, under 980 nm excitation, it displays (i) upconverting PL of the UCTm (at the blue, red and NIR-I, ca. 800 nm, regions); (ii) two-photon PL of AuNC; and (iii) down-shifting PL of thulium (around 1470 nm). The occurrence of energy transfer from UCTm to AuNCs in the UCTm@AuNC NHS was evidenced by the drastic lengthening of the AuNC PL lifetime (τPL) (from few hundred nanoseconds to more than one hundred microseconds). Initial biological assessment of UCTm@AuNC NHSs in vitro revealed high biocompatibility and bioimaging capabilities upon near-infrared excitation.

Comprehensive Photophysical and Nonlinear Spectroscopic Study of Thioanisolyl‐Picolinate Triazacyclononane Lanthanide Complexes

AbstractDetailed photophysical studies of luminescent lanthanide complexes are presented and elaborated using a newly developed thioanisolyl‐picolinate antenna and the related tacn macrocyclic ligand. The new ligand proved to sensitise Nd(III), Sm(III), Eu(III) and Yb(III) emission. Eu(III) complex showed complete energy transfer, yielding high quantum yield (44 %) and brightness, while the Tb(III) analogue underwent a thermally activated back‐energy transfer, resulting in a strong oxygen quenching of the triplet excited state. Transient absorption spectroscopy measurements of Gd(III), Tb(III) and Eu(III) compounds confirmed the sensitization processes upon the charge‐transfer antenna excitation. The triplet excited state lifetime of the Tb(III) complex was 5‐times longer than that of the Gd(III) analogue. In contrast, the triplet state was totally quenched by the energy transfer to the 4f‐metal ion in the Eu(III) species. Nonlinear two‐photon absorption highlighted efficient biphotonic sensitization in Eu(III) and Sm(III) complexes. In case of the Nd(III) compound, one‐photon absorption in 4f–4f transitions was predominant, despite the excitation at the antenna two‐photon band. This phenomenon was due to the Nd(III) 4f–4f transitions overlapping with the wavelength‐doubled absorption of the complex.

Luminescence intensity ratio by three thermalized levels in YAG:Er3+/Yb3+ nanoparticles

Luminescence thermometry is a remote temperature sensing method by observing temperature dependent spectral changes for temperature readout. Chase for increasing temperature readout sensitivity motivated research of employing 3rd thermalized level of Er3+ emission in Yb3+/Er3+ upconversion photoluminescence. For this purpose, highly stable and efficient yttrium aluminium garnet (YAG): Yb3+/Er3+ nanoparticles were prepared by a modified Pechini method. The emission spectra were recorded from 300 to 800 K, and two luminescence intensity ratios between emissions of 4S3/2, 2H11/2, and 4F7/2 were obtained. Apart from excellent matching theoretical predictions, the readout by using the 4F7/2 method provided a 3.5-fold increased relative sensitivity over the luminescence intensity ratio by 2H11/2 level, which is limited by being usable only above 600 K. The method by emission from 2H11/2 is to be used from 300 to 600 K, while emission from 4F7/2 provides the best luminescence intensity ratio at temperatures from 600 K to 800 K. YAG:Yb3+/Er3+ nano-particles proved to be an excellent sensor material for the luminescence intensity ratio method by employing multiple thermalized levels.

Influence of Au0 metallic particles on NIR laser emission of Yb3+ ions in Li2O−HfO2−SiO2 glass ceramic

This study consists of the synthesis, characterization, and analysis of photoluminescence (PL) spectra for Li2O−HfO2−SiO2−Yb2O3 glass ceramics sensitized with small amounts of Au2O3. Using the results of XRD and X-ray photoelectron spectroscopy (XPS) studies indicated a progressive reduction of Au3+ ions into Au0 metallic particles (MPs) with increase of Au2O3 content. Investigations into the infrared spectra highlighted a growing concentration of induced defects in the samples due to the increased proportion of Au0 MPs. Optical absorption (OA) spectra exhibited a distinct band attributed to the 2F7/2 → 2F5/2 transition of Yb3+ within wavelength range of 800–980 nm. Furthermore, a wide absorption band linked to the surface plasmon resonance (SPR) of Au0 MPs was identified in the visible region. PL spectra, recorded at λexc = 450 nm, revealed a band between 980 to 1025 nm, associated with the 2F5/2 → 2F7/2 transition of Yb3+ ions. Another emission band was observed due to the sp → d transition of Au0 MPs within the visible region. Observed enhanced PL emission from Yb3+ ions in the NIR range was ascribed to the energy transfer from Au0 MPs to Yb3+ ions. Ultimately, it was deduced that Au0 MPs played a pivotal role in enhancing the PL output of Yb3+ ions in the Li2O−HfO2−SiO2 glass ceramic. Thus, glass ceramics incorporating an optimal concentration of Au2O3 hold significant potential as materials for NIR lasers.

Color Tuning and Optical Temperature Sensing Properties of Upconversion Emission in Yb3+/Er3+/Tm3+Doped Boro-Zinctellurite Glasses

Zinc borotellurite (B2O3/BaO/ZnO/TeO2) glasses co-doped with Tm3+/Yb3+, Er3+/Yb3+ and tri-doped Tm3+/Er3+/Yb3+ were prepared using the traditional melt quenching method. Optical absorption spectra were measured in the wavelength range of 350 nm-1100 nm at room temperature. The optical bandgap (Eg) and Urbach energy were calculated from Tauc’s plot. Blue and green emissions that can be seen by the naked eye were generated under 975 nm laser light excitation in doped Tm3+/Yb3+ and Er3+/Yb3+ doped glasses. Shifts in both blue and green color coordinates were seen as the excitation power density increased from 0.5 to 15.1 W cm−2. A white light generation was generated in glass doped with Tm3+/Er3+/Yb3+ ions, although a noticeable shift was not observed in both blue and green color coordinates for the same excitation power density range. Temperature sensing properties were investigated using the fluorescence intensity ratio of upconversion green emissions from the two thermally coupled 2H11/2 and 4S3/2 levels of Er3+ ions between 304 K and 443 K. The maximum sensitivity of the glasses doped with Er3+ and Er3+/Yb3+ were found to be 7.2 × 10−3 K−1 and 1.2 × 10−2 K−1 at 429 K, respectively.

Laser-Induced Tunable White Light Emission in Yb3+/Er3+/Tm3+ Ion-Doped La2Ti2O7

A series of compounds with the general formula (La1−xREx)2Ti2O7 (x = 0.005, 0.015, and 0.025) doped with Yb3+, Er3+, and Tm3+ rare Earth ions were prepared by the traditional solid-state reaction at 1350 °C for 24 h. The X-ray powder diffraction technique, high-resolution transmission electron microscopy, and photoluminescence spectroscopy technique were used to characterize the structure and optical properties of the compounds. All compounds showed a single-phase orthorhombic structure with a space group Pna2 1, as confirmed by JCPDS (Cart No: 01-070-1690). The La1.9Yb0.04Er0.01Tm0.05 Ti2O7 nanocrystals exhibited intense tunable white light luminescence signals in the full spectrum, and green and blue emissions were predominant in the Yb3+/Er3+− and Yb3+/Tm3+-doped titanates, respectively. In this study, the influence of concentration and excitation power on the upconversion luminescence, color, and calculated laser-power-induced heating performance of La2Ti2O7 nanophosphors were investigated at room temperature.

LIBS assisted PCA analysis of multiple rare-earth elements (La, Ce, Nd, Sm, and Yb) in phosphorite deposits

In the present study, the immediate detection of rare-earth elements (REEs) in phosphorite deposits has been reported using laser-induced breakdown spectroscopy (LIBS). Numerous emission lines corresponding to the REEs such as lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), and ytterbium (Yb), have been detected in the emission spectra of phosphorite-induced plasma plume. For the quantitative analysis, we employed the calibration-free LIBS (CF-LIBS), and Energy Dispersive X-ray (EDX) spectroscopy techniques. The results obtained using the CF-LIBS technique show excellent agreement with that obtained by EDX. Besides principal component analysis (PCA) was employed by incorporating the LIBS spectral data of rare earth phosphorite rocks samples containing La, Ce, Nd, Sm, and Yb emission lines. The first three PCs were observed using LIBS spectral data set showing a covariance (interpretation rate) up to 76.3%. This study suggests that LIBS yields a quick and very reliable qualitative and quantitative analysis of REEs in any geological ore sample.

Linear polarization emission of Yb:YAG laser via polarization mode frequency locking

Direct linear polarization emission from a diode-pumped Yb:YAG laser is realized by changing the intracavity loss anisotropy which is controlled by finely adjusting the resonator. A theoretical model describing the relationship between loss and phase anisotropy on the frequency difference of polarization eigenmode has been established. The frequency difference of the polarization eigenmodes is investigated by recording the beat-note with a radio-frequency spectrum analyzer. By slightly tilting the output coupler, the beat-note frequency varied with the polarization state of the Yb:YAG laser. When the beat-note frequency disappeared, the laser was highly linearly polarized. The analysis of the beam profile of the linearly polarized output shows that the output originated from the coherent combination between two orthogonal polarization eigenmodes. The experimental results are in good agreement with the calculated results. Our research results confirm that the linearly polarized output in the isotropic laser can be realized by polarization eigenmode frequency locking.

Construction of a Near-Infrared Luminescent 48-Metal Rectangular Zn(II)-Yb(III) Nanocluster with Carbonate Templates for the Dual-Emissive Detection of Rutin as a Medicinal Ingredient.

An interesting 48-metal Zn(II)-Yb(III) nanocluster (1) with a size of about 1.3 × 2.8 × 3.1 nm was constructed by carbonate templates from a Schiff base ligand. It exhibits ligand-centered emission and near-infrared (NIR) luminescence of Yb(III), which are used in the dual-emissive detection of rutin (Rut) with high sensitivity even in the presence of other interferences. The response behavior can be expressed by the second-order equation I980nm/I510nm = A*[Rut]2 + B*[Rut] + C, and the limits of detection to Rut for the emissions of 1 are 2.23 μM and 0.20 nM.

Sensitization Pathways in NIR-Emitting Yb(III) Complexes Bearing 0, +1, +2, or +3 Charges.

Yb(III) complexes of macrocyclic ligands based on 1,4,7,10-tetraazacyclododecane were synthesized. The ligands carried a carbostyril chromophore for Yb(III) sensitization, and carboxylate or carbamide donors for metal binding, forming complexes of 0, +1, +2, or +3 overall charge. The coordination geometry was little affected by the replacement of carboxylates with amides, as shown by paramagnetic 1H NMR spectroscopy. The Yb(III)/Yb(II) reduction potentials were dependent on the nature of the metal binding site, and the more positively charged complexes were easier to reduce. Carbostyril excitation resulted in Yb(III) luminescence in every complex. The residual carbostyril fluorescence quantum yields were smaller in complexes containing more reducible Yb(III) centers decreasing from 5.9% for uncharged complexes to 3.1-4.4% in +3 charged species, suggesting photoinduced electron transfer (PeT) from the antenna to the Yb(III). The relative Yb(III) luminescence quantum yields were identical within the experimental error, except for the +3 charged complex with fully methylated coordinating amides, which was the most intense Yb(III) emitter of the series in water. Quenching of the Yb(III) excited state by NH vibrations proved to limit Yb(III) emission. No clear improvement of the Yb(III) sensitization efficiency was shown upon faster PeT. This result can be explained by the concomitant sensitization of Yb(III) by phonon-assisted energy transfer (PAEnT) from the antenna triplet excited state, which was completely quenched in all of the Yb complexes. Depopulation of the triplet by PeT quenching of the donor singlet excited state would be compensated by the sensitizing nature of the PeT pathway, thus resulting in a constant overall sensitization efficiency across the series.

Synergistically enhanced ultraviolet emission of Yb doped ZnO films by using a capping of ultrathin Al and SiO2 microspheres.

We studied the enhancement effects of ultraviolet (UV) emission from rare earth ytterbium (Yb) doped ZnO films, by using capping layers of Al and SiO2 micro-spheres. The films were deposited on Si substrates with magnetron sputtering followed by high temperature (∼1000°C) heat treatment, and then capped with a nanoscale ultrathin aluminum (Al) layer and/or SiO2 micro-spheres on the surface of the films. The photoluminescence (PL) results indicate that compared to the case without any capping, the UV emission is enhanced by a factor ranging from several to dozens times, the films capped with 2.0 nm Al layer and 5.0 µm SiO2 microspheres have the longest highest PL intensity among the samples. The PL enhancements are discussed in terms of increased optical (or electrical) fields around the surface of the films combined with defect passivation after the capping. Our work has proposed a strategy to enhance the UV emissions of ZnO, which will broaden the application potential of ZnO in UV photonics.

White-light emission in Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α-NiMoO4 nanoparticles

Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α-NiMoO4 nanoparticles were synthesized using a microwave hydrothermal method and studied for white-light emission under 980 nm laser diode excitation. White upconversion (UC) light was successfully obtained with the appropriate control of blue, green, and red emissions by successfully tuning the Er3+ and Ho3+ concentrations in Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α-NiMoO4, respectively. In addition, the white color emission was shown by the CIE chromaticity coordinates of samples. The energy transfer mechanisms are explained in detail based on the emission spectra and pump power density-dependent UC luminescence intensity in rare earth (Yb3+/Er3+/Tm3+ and Yb3+/Er3+/Tm3+/Ho3+)-doped α-NiMoO4 nanoparticles. The results indicate that Yb3+/Er3+/Tm3+- and Yb3+/Er3+/Tm3+/Ho3+-doped α-NiMoO4 nanoparticles can be good candidates for white-light devices.

Amplified spontaneous emission increased by waveguiding in thin-rod active elements.

The effect of amplified spontaneous emission in Yb:YAG thin-rod active elements under end diode pumping was studied numerically and experimentally with allowance for its waveguide propagation. It was shown that the waveguide propagation increases the effect significantly and notably influences gain and stored energy in this geometry. The influence of active element parameters and boundary conditions is analyzed.

Microstructure and laser emission of Yb:CaF2 transparent ceramics fabricated by air pre-sintering and hot isostatic pressing

Transparent ytterbium doped calcium-fluoride (Yb:CaF2) ceramics were successfully fabricated by air pre-sintering and hot isostatic pressing (HIP) post-treatment from the powders synthesized by the co-precipitation method. The influence of pre-sintering temperature on the densification, microstructures and optical quality of 5 at.% Yb:CaF2 ceramics was systematically investigated. The ceramic sample pre-sintered at 650 °C for 2 h and HIP post-treated at 650 °C for 1 h shows the best transparency with the in-line transmittance of 90% at 1200 nm. The upper level lifetime of the Yb3+ in Yb:CaF2 ceramics was evaluated to be 1.95 ms by the pinhole method. In addition, the laser emission from an optimized 5 at.% Yb:CaF2 ceramic sample yields in the maximum output power of 0.81 W with a maximum slope efficiency of 22.6% at 1028.5 nm under quasi-CW pumping.

Emission colour tuning of Mn, Yb, Er-NaGdF4 upconverting nanoparticles by energy density variation and pulse modulation

We describe, for the first time, the effects of Mn co-doping on the upconversion emission of Yb, Er - NaGdF4 nanoparticles using an ns pulsed laser with variable energy density and pulse width modulation. Unlike cw excitation that leaves unchanged the emission colour with power density, ns pulsed excitation induced a remarkable green to orange colour tuning with the increase of the energy density from 3 to 70 mJ/cm2. Pulse width modulation from 0.02 to 5 ms determines green to yellow colour tuning for 10% Mn, which is well-correlated with the built and decay stages of Er green and red emissions. Our study gives new insights into Mn role in colour tuning of Mn, Yb, Er - NaGdF4 nanoparticles and highlights the potential of these systems for anti-counterfeiting, bioimaging and lifetime multiplex applications.

Upconversion and near infrared emission in Yb–Tm mediated by ZnTe crystals in oxide glasses

This work presents a detailed investigation of the blue and near infrared (NIR) emission of Tm3+ and Yb3+ ions in ZnTe doped oxide glasses. Absorption, luminescence and lifetime measurements were performed in order to optimize the luminescent properties of Yb3+ and Tm3+. The influence of ZnTe and Yb3+ concentration on the enhancement and quenching of the emissions at 470 nm and 980 nm were determined. It was observed that the Yb3+ luminescence increases by a factor of 10, while the Tm3+ blue emission at 470 nm is quenched for both the presence of Yb3+ and ZnTe. The enhancement in the Yb3+ emission is attributed to the presence of ZnTe. Moreover, it is demonstrated that the glass can be pumped with additional wavelengths (325 nm and 532 nm) due to the absorption from the ZnTe semiconductor, allowing alternative pumping schemes. Calculations of the energy transfer microparameters from Yb3+-Yb3+ and Yb3+-Tm3+ were also performed, evaluating the influence of ZnTe in the process.