Nm In Er Research Articles

Ratiometric optical temperature sensing properties based on up-conversion luminescence of novel NaLaTi2O6:Yb3+,Er3+/Ho3+ phosphors

To satisfy the increasing necessity of contactless optical thermometry, utilizing both thermally coupled (TCLs) or non-thermally-coupled (NTCLs) energy levels of rare earth ions in novel phosphors has significant potential for devising the optical thermometers with high temperature sensitivity. Herein, a sequence of novel Yb3+,Er3+/Ho3+ doped NaLaTi2O6 (NLTO) phosphors were sintered using a high-temperature solid-state reaction approach. Structure, phase component and luminescence performance were identified in detail. Upon 980 nm near-infrared (NIR) excitation, the obtained materials presented typical Er3+/Ho3+ characteristic emission wavelengths in visible region, which include two green emission bands around 522 and 543 nm, as well as a weaker red band around 661 nm for Er3+ doped NLTO, a green emission band around 545 nm and a red band around 657 nm for Ho3+ doped NLTO. Besides, a unusual emission band around 757 nm of Ho3+ in visible edge region was also clearly found. The temperature sensing properties of representative NLTO:Yb3+,Er3+/Ho3+ samples were assessed based on the fluorescence intensity ratio (FIR) technique of TCLs or NTCLs energy levels. The maximal absolute sensitivity (Sa) and relative sensitivity (Sr) were determined to be 0.0374 K-1 (293 K) and 0.970% K-1 (293 K) by taking the FIR of NTCLs 2H11/2→4I15/2 and 4F9/2→4I15/2 transitions in NLTO:Yb3+,Er3+. Simultaneously, the maximal Sa and Sr were 0.0306 K-1 (573 K) and 0.776% K-1 (373 K) using the FIR of NTCLs 5F5→5I8 and 5F4,5S2→5I7 transitions in NLTO:Yb3+,Ho3+. Consequently, the temperature sensitivities above can be compared to reported results, which indicate that as-prepared materials have a promising application in optical temperature sensors field.

New Na5Y(MoO4)4: Yb3+, Er3+ phosphors: Up-conversion luminescence and temperature sensing characteristics

Currently, the development of new up-converting fluorescent materials for manufacturing optical temperature sensing device with high accuracy and precision has always been significant pursuits of many researchers. In this work, we have synthesized new Na5Y(MoO4)4: Yb3+/Er3+ phosphors via solid-state reaction route, and the influences of dopant concentration on UCL performance were discussed. The results revealed that the introduction of Yb3+ enhanced the luminescence intensity, and the optimal concentration combination was 0.20Yb3+/0.04Er3+. Doping Yb3+ and Er3+ did not affect the phase structure of the phosphor. Several emission peaks at 529, 552 and 668 nm of Er3+ were found to be temperature-dependent within the scope of 298–573 K. Through the utilization of fluorescence intensity ratio technique (FIR, I529/I552 and I529/I668), dual-mode temperature measurement was realized. The maximum relative sensitivity (Sr-max) of 1.77 % K−1 (@298 K) utilizing thermally coupled energy levels (TCELs) and the maximum absolute sensitivity (Sa-max) of 12.0 % K−1 (@573 K) based on the non-TCELs were achieved. Furthermore, Yb3+/Er3+ co-doped Na5Y(MoO4)4 phosphors exhibited excellent photothermal repeatability and temperature resolution. The results indicated that the novel Na5Y(MoO4)4 phosphor provided the possibility for the development of temperature sensing materials with high sensitivity.

Efficient near‐infrared emission in lanthanum ion doped double perovskite Cs2NaScCl6 via Cr3+ sensitization under visible light excitation

AbstractHerein, we synthesized Cr3+/Ln3+ (Er3+, Tm3+)‐codoped rare earth‐based Cs2NaScCl6 double perovskite, and the near‐infrared emission of Ln3+ can be excited by visible light through the energy transfer (ET) from Cr3+ to Ln3+. Moreover, there are two independent emission bands, which stems from 4T2 → 4A2 transition of Cr3+ (970 nm) and f‐f transition of Ln3+ (1542 nm for Er3+ and 1220 nm for Tm3+), respectively. Particularly, both compounds have ultra‐high photoluminescence quantum yield (PLQY) of 60% for 10%Cr3+/6%Er3+‐codoped Cs2NaScCl6 (Er3+ emission: ∼26%) and 68% for 10%Cr3+/4.5%Tm3+‐codoped Cs2NaScCl6 (Tm3+ emission: ∼56%), which can be attributed to the ultra‐high ET efficiency from Cr3+ to Ln3+ and the similar ionic activity of Sc3+ and Ln3+ allowing more dopants enter the host lattice. Considering the excellent stability of the samples, we demonstrated Cr3+/Tm3+‐codoped Cs2NaScCl6 in the applications of near‐infrared imaging and night vision. Finally, we reported 10%Cr3+/4.5%Tm3+/9%Er3+‐tridoped Cs2NaScCl6 and further applied it for optical thermometry.image

Luminescence properties of Er3+ doped high density germanate glass scintillators for X-ray computed tomography (CT)

Er3+ doped high density germanate glasses with compositions of 50GeO2-10BaO–10Al2O3-15Lu2O3-(15-x) La2O3-xEr2O3 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0, in mol%) have been prepared by the melt-quenching method. The optical and physical properties of the samples were characterized by differential scanning calorimetry (DSC), density, transmittance spectra, photoluminescence (PL) spectra, and X-ray excited luminescence (XEL) spectra. The densities were in the range from 5.90 to 6.07 g/cm3. The strong green emissions around 552 nm of Er3+ were observed upon the excitations of 378 nm light and the X-ray, and the lifetimes of 552 nm emission were in the range of 20.88–96.47 μs. The results show that Er3+ doped high density germanate glasses could be used as potential scintillators for X-ray CT.

Broadband near-infrared emission covering S+C+L in Er3+-doped nanocrystal modified PbO-PbF2-Bi2O3-Ga2O3 glasses

This paper reports a broadband near-infrared emission ranging from 1400 to 1660 nm in Er3+-doped nanocrystal-modified PbO-PbF2-Bi2O3-Ga2O3 glasses. After heat treatment, X-ray diffraction measurements were performed and confirmed that PbBiO2F nanocrystals were precipitated in the precursor glasses. As nanocrystals alter the local environment around Er3+ ions, the emission spectrum of the transition 4I13/2→4I15/2 is broadened and enhanced, resulting in a broadband emission and an FWHM wavelength range of 143.4 nm from 1470.1 to 1613.5 nm, which overlaps the S+C+L optical communications windows. In addition, the emission intensity of the 4I11/2→4I13/2 transition is also found to be increased after heat treatment, thus enhancing the λ∼2750 nm emission intensity. Our results indicate that an Er3+-doped nanocrystal-modified PbO-PbF2-Bi2O3-Ga2O3 glass could be a competitive candidate material that can offer improved bandwidths for S+C+L broadband amplifiers used in very high-capacity optical communications systems.

Enhanced near-infrared emission of Er3+ as a synergistic effect of energy transfers in Bi3TeBO9:Yb3+/Er3+ phosphors

Enhanced near-infrared emission at 1531 nm of Er3+ ions excited by Bi3+ and/or Yb3+ ions was revealed in Bi3TeBO9:Yb3+/Er3+ phosphors. The microcrystalline powders investigated: Bi3TeBO9:Er3+, Bi3TeBO9:Yb3+ and Bi3TeBO9:Yb3+/Er3+ were synthesized by means of the modified Pechini method. Their hexagonal structure with P63 space group was confirmed by XRD measurements. The morphology of the above-mentioned samples was analyzed using SEM technique. The results of μ-Raman investigations showed low phonon energy of Bi3TeBO9 matrix. The characteristic Er3+ emission at 1531 nm assigned to the 4I13/2 → 4I15/2 transition in Bi3TeBO9:Er3+ and Bi3TeBO9:Yb3+/Er3+ powders was excited by Bi3+ or Yb3+ ions (the 1S0 → 3P1 or 2F7/2 → 2F5/2 transitions) upon their excitation at 327 or 975 nm, respectively. It was revealed that the effective energy transfer from the excited Bi3+ ions (at 327 nm) directly to Er3+ ions or indirectly to Er3+ ions both via the excitation of Bi3+ ions in VIS range or excitation of Yb3+ ions in the NIR range results in synergistic effect, which produces enhanced emission at 1531 nm of Er3+ ions in Bi3TeBO9:Yb3+/Er3+ system. Moreover, it was found that the effective energy transfer from the excited Yb3+ ions (at 975 nm) directly to Er3+ ions results in the efficient emission at 1531 nm of Er3+ ions. Furthermore, the calculations of energy transfer efficiency and quantum efficiency proved the effective energy transfer from Bi3+ to Yb3+ and from Yb3+ to Er3+ ions. The corresponding mechanisms of energy transfer processes in the investigated materials were discussed on the basis of reflectance, excitation and emission spectra and measured decay times. The results indicate a potential of the use of Bi3TeBO9:Yb3+/Er3+ powders as spectral converters in new generation of photovoltaic devices.

Synthesis and characterization of thermally evaporated Er-doped SnO2 thin films for photonic applications

In this study, different compositions of transparent films of erbium-doped tin oxide were created utilizing the thermal evaporation process on glass substrates. The tetragonal phase is verified by XRD analysis. The visible spectrum's strong transmittance was seen in the films. The films' transmission spectra ranged from 75 to 85% transmittance in the visible range with varying Er concentrations. Using Tauc's relation, values of the optical direct band gap have been calculated. The rutile phase of tin oxide is indicated by the Raman scattering peaks. PL measurements show thatonly the emission-related on a peak at 656 nm of Er3+ ions due to transition from 4I15/2 to 4F9/2 level and with the presence of doping, this emission becomes more intense. From the AFM measurements, the RMS roughness and grain size of films were computed. The results obtained show that these samples have wide applications in optoelectronic devices.

Dual-mode optical ratiometric thermometer based on rare earth ions doped perovskite oxides with tunable luminescence

Rare earth ions doped luminescent materials have drawn considerable attention as they can generate both upconversion and downshifting emissions. Here, the rare earth ions Pr3+/Er3+ codoped perovskite oxide Bi4Ti3O12 is proposed as a dual-mode temperature sensor and anti-counterfeiting material based on its up/down-conversion luminescence. Under 481 nm excitation, the intensity ratio of green emission (∼523 nm in Er3+) and red emission (∼611 nm in Pr3+) brings about a very high absolute sensitivity (Sa) of 2% K−1 at 568 K and a maximum relative sensitivity (Sr) of 1.03% K−1 at 478 K in the temperature range of 298–568 K. In addition, the upconversion green emissions of Er3+ yield a relatively-high Sr of 1.1% K−1 at 298 K with 980 nm excitation, which can provide self-calibration coupled with down-conversion luminescence temperature sensing mode. Besides, this phosphor also shows tunable luminous colors for the potential application in the anti-counterfeiting field under various excitation wavelengths.

Fabrication of Er, Tb doped CuO thin films using nebulizer spray pyrolysis technique for photosensing applications

CuO-based high-performance photo-sensors are a key area of research and challenge in today's scenario. In view of this, we study undoped, CuO:Er (1%),CuO:Tb (1%), and Er(1%),Tb(1%) dual doped CuO thin films for photodetector applications using the nebulizer spray pyrolysis technique. The structural, morphological, and optical features of the coated samples were systematically studied using few techniques such as X-ray diffraction (XRD), Scanning electron microscope (SEM), UV–Vis spectra, Photoluminescence (PL) and two probes. According to the XRD analysis, all the doped thin films show a good crystalline structure with a predominant peak exhibition (002) plane and the doping process enlarged the crystallite size value and obtained a maximum of 44 nm for Er,Tb dual doped CuO film. SEM photo shows the formation of a flaky nanoparticle structure. In the case of light absorption, the absorption level depends on dopant materials such as Er and Tb and the UV absorption level is improved for the dual doped film. The photo-luminescence shows that all the prepared samples exhibit defect-related peaks around 412, 450, 475, 525 nm and the doping process significantly improves the luminescence properties of CuO films. According to Hall effect analysis all prepared samples show the p-type characteristics whose film resistance and mobility are increased and the highest value is noted for Er(1%),Tb(1%) doped CuO thin film. The photo-detection capacity was studied by the analysis of optoelectronic properties for these doped CuO thin films. The UV sensing study indicates, high responsivity (4.85⨯10−1AW−1), external quantum efficiency (113%), and detectivity (1.89⨯1010 Jones) values for the Er, Tb dual doped CuO photodetector. The work also discusses a possible mechanism of ultraviolet photo-detector performance. These findings share a guideline to develop a high-performance photodetector.

Dye-Sensitized Rare Earth-Doped Nanoparticles with Boosted NIR-IIb Emission for Dynamic Imaging of Vascular Network-Related Disorders.

Real-time dynamic vascular network imaging can provide accurate hemodynamic and anatomical information, facilitating the diagnosis of blood circulatory system-related diseases and achieving precise evaluation of therapeutic effects. In vivo luminescence imaging in the NIR-IIb biological window (1500-1700 nm) has developed into a next generation of optical imaging method with significantly improved temporal-spatial resolution and penetration depth. Unfortunately, an imaging contrast agent capable of emitting NIR-IIb luminescence with sufficient brightness in this region is lacking. Herein, we designed and proposed a type of dye-sensitized rare earth-doped nanoparticle (RENPs@Alk-pi) with obviously boosted NIR-IIb emission and high biocompatibility, which can be used to realize the real-time NIR-IIb luminescence imaging with high temporal-spatial resolution and contrast. The dye sensitization process provides a 40-fold enhanced brightness of the NIR-IIb emission at 1525 nm of Er3+. Consequently, the RENPs@Alk-pi was not only able to depict a vascular network but also applicable in noninvasively monitoring the dynamic vascular processes and changes in the vascular anatomy of two blood circulatory system-related disorders, including hindlimbs ischemia and atherosclerosis. Our research provides a powerful tool for evaluating vascular network-related dysfunction and physiological processes.

Efficient upconversion emission and high-sensitivity thermometry of BaIn2O4:Yb3+/Tm3+/RE3+ (RE = Er3+, Ho3+) phosphor.

BaIn2O4:Yb3+/Tm3+/RE3+ (RE = Er3+, Ho3+) upconversion (UC) phosphors were synthesized via the sol-gel method. Rietveld refinement based on XRD data proved that In3+ ions were replaced by rare earth (RE) ions. Under 980 nm excitation, UC and optical temperature-sensing properties were investigated, and the results indicated that the samples demonstrated high UC emission efficiencies and bright emission visible to the naked eye. The luminescence intensity ratio (LIR) technology based on thermally and non-thermally coupled levels was applied to study the optical temperature-sensing properties of the RE-doped BaIn2O4 phosphors. For the BaIn2O4:Yb3+/Tm3+/Er3+ phosphor, the absolute sensitivity reached a maximum value of 0.1433 K-1 at 473 K, which was based on the non-thermally coupled levels (non-TCLs) of 1G4 (blue luminescence at 480 nm of Tm3+ ion) and 2H11/2 (green luminescence at 525 nm of Er3+ ion). For the BaIn2O4:Yb3+/Tm3+/Ho3+ phosphor, the maximum absolute sensitivity was 0.2545 K-1, which came from the non-TCLs of 3H4 (infrared luminescence at 795 nm of Tm3+ ion) and 1G4 (blue luminescence at 480 nm of Tm3+ ion). BaIn2O4:Yb3+/Tm3+/RE3+ (RE = Er3+, Ho3+) samples were proven to have excellent optical temperature-sensing properties and could be applied to design optical thermometry.

Isothermal section of the Er-Mn-Sn system at 670 K

Interaction between the components in the Er - Mn - Sn ternary system was studied at 670 K over the whole concentration range using methods of X-ray diffractometry, metallography and electron microprobe analysis. The alloys for investigation were prepared by direct arc melting the stoichiometric amounts of the constituent elements under high purity Ti-gettered argon atmosphere on a water-cooled copper hearth. The arc-melted ingots were then annealed at 670 K in evacuated quartz glass tubes for 720 hours and subsequently cold water quenched. The synthesized and annealed samples are stable in atmospheric conditions. For the characterization of the annealed samples X-ray powder diffraction on DRON-2.0m diffractometer with Fe K α radiation was performed. The chemical and phase compositions of the obtained samples were examined by Scanning Electron Microscopy (SEM) (REMMA-102-02 electron microscope). A formation of the all binaries in the Er-Sn, Er-Mn and Mn-Sn systems which delimit the studied Er-Mn–Sn was confirmed. According to EPMA data the homogeneity range of Mn 2 Snbinary is limited by the Mn 67,81 Sn 32,19 and Mn 63,87 Sn 36,13 compositions. At the temperature of investigation phase relations in the Er-Mn-Sn system are characterized by existence of two ternary compounds ErMn 6 Sn 6 (MgFe 6 Ge 6 structure type, space group P 6/ mmm , a =0.55157(7) nm, с =0.90051(1) nm) and Er 4 Mn 4 Sn 7 (Zr 4 Co 4 Ge 7 structure type, space group I 4/ mmm , a =1.4869(3) nm, c =0.5951(1) nm). During investigation of Er-Mn-Sn system the existence of interstitial solid solution ErMn 0- х Sn 2 based on the ErSn 2 binary (ZrSi 2 -type) was observed. The solubility of Mn atoms was found to be up to 5 at. % at 670 K. The lattice parameters change from а = 0.4369(9), b = 1.16138(8), с = 0.4273(9) нм nm (for ErSn 2 compound) to а = 0.4370(8), b = 1.6141(9), с = 0.4287(4) nm for Er 32 Mn 5 Sn 63 sample. Limited composition of the solid solution was confirmed by results of EDX analysis (Er 32.44 Mn 4.88 Sn 62.68 ). Solubility of the third component in other binary compounds is less than 1-2 at. %. Analysis of the Er-Mn-Sn system and studied early {Y, Ce, Nd, Gd, Dy}-Mn-Sn showed that the ternary R-Mn-Sn systems are characterized by small number of the intermediate phases. Stannides with CeNiSi 2 and Gd 3 Cu 4 Ge 4 structure types are formed only in the systems with rare earths of Cerium group. R-Mn-Sn systems where R is a rare earth element of Yttrium group are characterized by formation of the ternary compounds with Zr 4 Co 4 Ge 7 -type and MgFe 6 Ge 6 structure types, which are realized in the studied Er-Mn-Sn system. Keywords: intermetallics, ternary system, phase equilibria.

Phase evolution, structure, and up‐/down‐conversion luminescence of Li6CaLa2Nb2O12:Yb3+/RE3+ phosphors (RE = Ho, Er, Tm)

AbstractGarnet‐type Li6Ca(La0.97Yb0.02RE0.01)2Nb2O12 (RE = Ho, Er, Tm) new phosphors were successfully synthesized via solid reaction at 900°C for 5 hours, whose course of phase evolution, macroscopic/local crystal structure and up‐/down‐conversion (UC/DC) photoluminescence were clarified. Mechanistic study and materials characterization were attained via XRD, Rietveld refinement, DTA/TG, electron microscopy (FE‐SEM/TEM), and Raman/reflectance/fluorescence spectroscopies. The phosphors were shown to exhibit UC luminescence dominated by a ~ 553 nm green band (5F4/5S2 → 5I8 transition) for Ho3+, a ~ 568 nm green band (4S3/2 → 4I15/2 transition) for Er3+ and a ~ 806 nm near‐infrared band (3H4 → 3H6 transition) for Tm3+ under 978 nm laser excitation, with CIE chromaticity coordinates of around (0.31, 0.68), (0.38, 0.60) and (0.17, 0.24), respectively. Analysis of the pump‐power dependence of UC intensity indicated that all the emissions involve a two‐photon mechanism except for the ~ 486 nm blue emission of Tm3+ (1G4 → 3H6), which requires a three‐photon process. The DC luminescence of these phosphors is featured by dominant bands at ~ 553 nm for Ho3+ (green, 5F4/5S2 → 5I8 transition), ~568 nm for Er3+ (green, 4S3/2 → 4I15/2 transition) and ~ 464 nm for Tm3+ (blue, 1D2 → 3F4 transition). The UC and DC properties were also comparatively discussed.

Sensitization effect between Ln3+ ions in zinc fluoride glasses for MIR applications

A system of zinc fluoride glasses were synthesized to analyse the sensitization mechanism between doped Ln3+ ions under 808 or 980 nm excitation. Differential scanning calorimetry (DSC) curve and Raman spectra indicate the favourable thermal stability and a low maximum phonon energy of the host. Judd-Ofelt (J-O) theory together with the absorption spectra were utilized to compute the Ωt for predicting radiative features of each sample which coincide with the later measured emission spectra. Broadband emission ranging from 2400 to 3300 nm with a half-width of 361 nm in Er3+/Dy3+ codoped zinc fluoride glasses under 980 nm pumping has been investigated, which may be applicated in mid-infrared fiber amplifier and broadband tunable lasers field. On the other hand, the efficient sensitization effect mechanism between Er3+ and Dy3+ around 3 μm band with an extremely high energy transfer efficiency Ƞ (96.1%) of Er3+:4I13/2→Dy:6H11/2 has been researched under 808 nm excitation. Hence, Er3+ and Dy3+ doped zinc fluoride glasses may be potential optical candidates of great development foreground in the fields of mid-infrared applications.

Optical temperature sensing based on thermal, non-thermal coupled levels and tunable luminescent emission colors of Er3+/Tm3+/Yb3+ tri-doped Y7O6F9 phosphor

The Er3+/Tm3+/Yb3+ tri-doped Y7O6F9 phosphor is synthesized by a typical hydrothermal method. The Y7O6F9: 0.6%Er3+/0.2%Tm3+/15%Yb3+ phosphor is selected for the study. The up-conversion characteristics and temperature sensing performances of the phosphor are investigated under the excitation of 980 nm laser. The temperature sensing performances are investigated in the temperature range of 306–546 K based on thermal and non-thermal coupled levels by using fluorescence intensity ratio technology. The maximum sensitivity is 54.3 × 10−3 K−1 at 546 K, which is based on 3F2,3 (red emission at 695 nm of Tm3+) and 4S3/2 (green emission at 545 nm of Er3+) levels. After comparison, it is found that the sensing sensitivity of Y7O6F9: 0.6%Er3+/0.2%Tm3+/15%Yb3+ phosphor is relatively high. The excellent temperature sensing performances of the phosphor are verified. What's more, the white luminescent emission of the phosphor is achieved by adjusting excitation power and sample temperature during the experiment. And the luminescent emission color of the phosphor can be modulated widely. The above experimental results not only enable us to have a deeper understanding of tunable upconversion luminescent emission and optical temperature sensing, but also provide a significant step for high sensitivity thermometry, white light illuminating and color displaying.

Raman scattering and cathodoluminescence properties of Er3+ and Eu3+ co-doped GaN films

GaN:Eu3+/Er3+ films were prepared via ion implantation method. All samples were investigated by Raman scattering and Cathodoluminescence (CL) spectra. Six new Raman peaks were introduced by Er3+ ions implantation at 181, 214, 238, 846, 880 and 911 cm−1, respectively. In addition, the intensity ratio of 560 nm with respect to 539 nm of Er3+ ions and the intensity ratio of 623 nm (belong to Eu3+) to 539 nm (belong to Er3+) both decrease with the Er3+ ions implantation concentration, which proved the existence of the energy transfer from Eu3+ to Er3+ by dipole-dipole interaction in GaN host. Finally, the chromaticity coordinate and color correlated temperatures could be changed through adjusting the ratio of Er3+ concentration with respect to Eu3+ concentration.

Structural and optical properties of TeO2-Li2O-ZnO-Nb2O5-Er2O3 glass system

Quinary tellurite glass system in the percentages of 75TeO2–5Li2O–10ZnO–(10–x) Nb2O5–xEr2O3 where (x = 0.0, 0.5, 1.0, 1.5, 2.0, and 2.8 mol%) have been prepared and characterized. Both Fourier-transform-infrared (FTIR) and Raman spectroscopies were performed to study the structural changes correlated with the glass network. The thermal characteristics of the system were specified which showed a higher thermal stability (>100 °C) due to the formation of more bridging oxygen's (BO's) revealed by (FTIR) and Raman spectroscopies. The optical absorption spectra within near UV–visible regions were performed, and exhibited nine absorption bands centered around 1536, 977, 798, 653, 545, 524, 490, 450, and 443 nm corresponding to the 4I15/2 ground state to the various excited states 4I13/2, 4I11/2, 4I9/2, 4F9/2, 4S3/2, 2H11/2, 4F7/2,4F5/2, and 4F3/2 respectively. The same measurement also showed increasing values of the optical band gap (Eg) form 2.70 to 2.90 (eV) and decreasing the refractive index (n) from 2.48 to 2.42. Both the extinction coefficient data and the complex dielectric functions of the glasses were estimated. The different optical parameters were distinctly affected by increasing the Er2O3 (mol %) and the structural changes. The radiative properties of the glass were calculated using J-O parameters. The Branching ratio (β) of 4I13/2 → 4I15/2 transition peaked at 1520.48 nm for Er3+ ions has the highest value (1.000) also, the radiative lifetime (τ) of the same transition changed from 1.4510 to 1.8483. The gain cross-section of the laser transition level from 4G11/2 → 4I15/2 changed from 1.44 × 10−20 to 1.92 × 10−20 cm−1 in the existing glass system. The acquired results exhibited that the existent glass can be a good candidate in the fiber drawing and laser, non-linear optical applications.

Crystal Structure of NaLuW2O8·2H2O and Down/Upconversion Luminescence of the Derived NaLu(WO4)2:Yb/Ln Phosphors (Ln = Ho, Er, Tm)

Hydrothermally reacting Lu(NO)3 and Na2WO4·2H2O at 200 °C and pH = 8 produced the new compound NaLuW2O8·2H2O, which was analyzed via the Rietveld technique to crystallize in the orthorhombic system (space group: Cmmm) with cell parameters a = 21.655(1), b = 5.1352(3), and c = 3.6320(2) Å and cell volume V = 403.87(4) Å3. The crystal structure presents -(NaO6)-(NaO6)- and -(LuO4(H2O)2WO5)-(LuO4(H2O)2WO5)- alternating layers linked together by the O2- ion common to NaO6 octahedron and WO5 triangle bipyramid. Tetragonal structured and phase-pure Na(Lu0.87Ln0.03Yb0.1)(WO4)2 phosphors (Ln = Ho, Er, and Tm) were directly produced by calcining their NaLuW2O8·2H2O analogous precursors at 600 °C for 2 h, followed by a detailed study of their downconversion/upconversion (DC/UC) photoluminescence. It was shown that the UC luminescence is dominated by a red band at ∼650 nm for Ho3+ (5F5 → 5I8 transition), green bands at ∼500-575 nm for Er3+ (2H11/2/4S3/2 → 4I15/2 transitions) and a blue band at ∼476 nm for Tm3+ (1G4 → 3H6 transition), all via a three-photon process. DC luminescence of the phosphors is characterized by a ∼545 nm green emission for Ho3+ (5F4/5S2 → 5I8 transition, λex = 453 nm), ∼500-575 nm green emissions for Er3+ (2H11/2/4S3/2 → 4I15/2 transitions, λex = 380 nm), and a ∼455 nm blue emission for Tm3+ (1D2 → 3F4 transition, λex = 360 nm), with CIE chromaticity coordinates of around (0.27, 0.71), (0.26, 0.72), and (0.15, 0.04), respectively.

Spectroscopic analysis of up conversion luminescence in doped halogeno-antimonite glass

The up-conversion emission of Nd3+, Sm3+ and Er3+ has been studied in a new halogeno-antimonite glass with the chemical composition 80 Sb2O3 – 10 ZnBr2 – 10 KCl. Doping concentration was 0.2 mol% of lanthanide (Ln) ions. Rare earths were introduced as fluorides LnF3 that were further converted into oxides. Main physical properties of base glass were measured, including density, thermal expansion, characteristic temperatures, refractive index and optical transmission. The amount of residual hydroxyls was calculated from the OH absorption band around 3000 nm. The recorded up-conversion emission lines are λem = 536 nm for Nd3+ pumped at 805 nm; λem = 563 nm, 600 nm, 631 nm and 645 nm for Sm3+ pumped at 945 nm; λem = 531 nm for Er3+ pumped at 798 nm. Co-doped glass (0.1 Yb3+ + 0.1 Er3+) pumped at 980 nm has three emission lines at 524 nm, 545 nm and 650 nm. Corresponding transitions have been identified and the mechanisms ruling the up-conversion process is discussed. They include excited state absorption (ESA), energy transfer (ET) cooperative energy transfer (CET), emission assisted by phonon (EAP), multiphonon relaxation (MR) and cross- relaxation (CR).

Investigation of energy transfer mechanism in Er3+ and Tm3+ doped AlN crystalline films

In this work, Er-implanted AlN, Tm-implanted AlN and Er, Tm co-implanted AlN were prepared. All samples were annealed after ion-implantation. The optical and structural properties of the samples were characterized by cathodoluminescence and X-ray diffraction, respectively. For Er-implanted AlN, the dominant sharp emission lines centered at 410 and 480 nm were observed. For Tm-implanted AlN, the dominant sharp emission line centered at 467 nm was observed. After Er was implanted into AlN: Tm, the intensity ratio of 370 nm and 467 nm in Er, Tm co-implanted AlN is almost 10 times of that in AlN: Tm. Meanwhile, the Tm emission lines centered at 685 nm and 776 nm disappeared, which can be illuminated on the viewpoint of near resonance energy transfer between Tm and Er in AlN host.