Energy Transfer Of Tm3 Research Articles

Optical properties and energy transfer of Tm3+ single-doped and Tm3+-Tb3+ co-doped transparent glass-ceramics containing NaGd(MoO4)2 single phase

Tm3+ single-doped and Tm3+-Tb3+ co-doped SiO2–B2O3–Na2O–ZnO–MoO3-Gd2O3 glasses were successfully prepared by the melt-quenching process. X-ray diffraction and transmittance measurements were used to determine that the optimal heat treatment regime consisted of crystallization at 620 °C for 5 h and transparent glass-ceramics containing the NaGd(MoO4)2 single phase were obtained. The characterization results by SEM confirmed that the size of the crystals precipitated in the glass matrix was on the nanometer level. The effects of different contents of Tm2O3 on the luminescent properties of glass-ceramics in this system were explored. The results showed that the emission peak at 453 nm (1D2→3F4) had the highest intensity when Tm2O3 was doped with 0.5 mol% under the wavelength at 359 nm excitation. In addition, with the gradual increase of Tb2O3 contents, the luminescence colour of the Tm2O3–Tb2O3 co-doped glass-ceramics gradually shifted from blue to green. This indicates its potential application in blue-green light display technologies and various other areas. The experimental results of the water resistance stability of the samples show that the co-doped glass-ceramic still has good luminescence stability after being immersed in water, which provides further favourable support for its application.

Blue and white light emissions and energy transfer in Tm3+ and Dy3+/Tm3+ doped lithium-aluminum-zinc phosphate glasses

Lithium-aluminum-zinc phosphate glasses doped with thulium and dysprosium ions are characterized by using spectroscopy techniques. The Judd-Ofelt parameters were evaluated to calculate the radiative parameters of thulium 1D23F4 and 1G43H6 visible transitions and 3H43F4 near infrared transition, which shows the highest optical amplification parameters. Upon 356 nm excitation, the Tm3+ doped phosphate glass emits blue light with CIE1931 chromaticity coordinates x = 0.1540 and y = 0.0283 and color purity around 96.8%. With excitations at 347 and 350 nm, the Dy3+/Tm3+ doped phosphate glass emits neutral and cold white light with correlated color temperature values of 4716 and 6628 K, respectively. The dysprosium emission decay time in the codoped glass is shorter than that in the Dy3+ single-doped glass, indicating a non-radiative energy transfer from Dy3+ to Tm3+. The dominant electrical interaction involved in the energy transfer, following the model Inokuti-Hirayama, is of dipole-dipole type. The energy transfer probability and efficiency are 769.0 s-1 and 0.53, respectively. Tm3+ doped and Dy3+/Tm3+co-doped lithium-aluminum-zinc phosphate glasses could be appropriate for blue and neutral/cold white light-emitting device applications.

Optical spectroscopy and energy transfer in Tm3+ - Ho3+ ions system in LiY0.3Lu0.7F4 mixed crystals

Here we present the study of spectral and kinetic characteristics of Tm3+ and Ho3+ ions system in LiY0.3Lu0.7F4 mixed crystal. Polarized spectra of absorption and luminescence transitions between 3F4 – 3H6 and 5I7 – 5I8 states of Tm3+ and Ho3+ ions respectively as well as energy transfer efficiency were investigated. It was shown that LiY0.3Lu0.7F4 mixed crystal provides some broadening of Tm3+ and Ho3+ spectral lines for 4f-4f intermultiplet transitions. The evaluated Förster energy transfer critical radius for LiY0.3Lu0.7F4: Tm3++Ho3+ (10 at. % + 2 at. %) crystal was 22 Å. The backtransfer efficiency from Ho3+ to Tm3+ in the described energy transfer process CHo-Tm results in value of 0.83 × 10−40 cm6/s and relation of froward and back-transfer coefficients CTm-Ho/CHo-Tm appears to be 6.8 calculated from our spectroscopic data, which make it prospective active medium for sensitized laser oscillation in IR spectral region.

Up-conversion luminescence and energy transfer of Tm3+-Yb3+ co-doped NaLaSiO4 crystalline phase glass-ceramics

Abstract In recent years, up-conversion luminescence has attracted much attention due to its wide range of applications, and the choice of host material often determines the luminescence properties. Despite the remarkable scientific and technological development of glass-ceramics in the last decades, research on up-conversion luminescence in silicate glass-ceramics still needs to be further developed. In this research work, glass ceramics with NaLaSiO4 crystalline phase were successfully precipitated in precursor glass co-doped with Tm3+-Yb3+. The transmittance of glass-ceramics was about 73% in the visible range. Efficient up-conversion of Tm3+ with blue emission was achieved by adjusting the concentration of Yb3+ under pumping at 980 nm. The optimal concentration of Yb3+ was 0.7%, above which a concentration burst occurred. The chromaticity coordinates at the optimum luminous intensity are (0.1101, 0.1495), which are located in the blue region. The research work suggests that this glass-ceramic has potential as a blue solid-state laser.

Broadband ∼2 μm luminescence properties and energy transfer in Tm3+/Ho3+ co-doped TeO2–Al2O3–BaF2 glass

Tm3+/Ho3+ co-doped tellurite aluminate glasses were prepared using the melt-quenching technique. Under 808 nm laser diode (LD) excitation, these glasses exhibit intense 2 μm band luminescence, with a full width at half-maximum (FWHM) of 144 nm. The energy transfer mechanism between Tm3+ and Ho3+ was explored to investigate the luminescence behavior further. Furthermore, the forward energy transfer coefficient (Tm3+→Ho3+) is greater than the backward energy transfer coefficient (Ho3+→Tm3+), indicating that Tm3+ can effectively sensitize Ho3+. As mentioned above, Tm3+/Ho3+ co-doped tellurite aluminate glass is a competitive material in the laser field.

Novel CeF3:Tm3+, Er3+ nanoparticles: NIR up-down conversion luminescence properties based on energy transfer of Tm3+ and Ce3+

A novel CeF3:Tm3+, Er3+ NIR up-down conversion luminescent nanoparticles with highly efficient visible and near-infrared second window (NIR-II) emission were synthesized by direct precipitation and hydrothermal methods. The two different emission modes of visible-NIR II light of Er3+were realized through the energy transfer of Tm3+ and Ce3+at the excitation wavelength of 808 nm. Which successfully combined the narrow emission peaks of visible light and the deep tissue penetration advantage of NIR-II. First, the effects of preparation conditions on the structure, morphology, stability and luminescence properties of CeF3:Tm3+, Er3+ nanoparticles were analyzed by XRD, SEM, TEM and PL. The results showed that the crystallinity, morphology and luminescence intensity of CeF3:Tm3+,Er3+ nanoparticles produced by hydrothermal method (reaction time of 10 h) were optimal compared with that of direct precipitation method. CeF3: Tm3+,Er3+ nanoparticles has better thermal stability, and fluorescence lifetime of 5D0→7F2 (525 nm), 4I15/2→4I11/2 (1066 nm) and 4I15/2→4I13/2 (1386 nm) for Er3+ are 15.51 ns, 48.78 us and 57.06 us, separately. At the same time, the surface of CeF3:Tm3+, Er3+ nanoparticles was modified by PEG and Lys. And then the effects of the surface modification on the hydration size, zeta potential and up-down conversion luminescent properties (visible and NIR-II light emission) were investigated. The results show that the modification of PEG effectively slows down the agglomeration of CeF3:Tm3+, Er3+ nanoparticles and improves their stability and dispersion under the same conditions. More importantly, the modification of PEG effectively increases the up-conversion luminescence intensity of CeF3:Tm3+, Er3+ nanoparticles under 808 nm excitation. Moreover, the CeF3:Tm3+, Er3+-PEG nanoparticles with 20–40 nm showed stronger NIR up-down conversion emission intensity in aqueous solutions (pH = 5,6,7) and better thermal stability. Furthermore, the CeF3:Tm3+, Er3+-PEG nanoparticles has low cytotoxicity and good biocompatibility. This study provides a theoretical basis for the development of high-performance rare-earth NIR up-down conversion luminescence materials.

Luminescence Characteristics and Energy Transfer of Tm3+-Doped Calcium Fluoroborate Glasses for Fiber Amplifiers

The conventional melt quenching method was employed to fabricate calcium fluoroborate glasses doped with Tm2O3 (CFBTm). Optical absorption and photoluminescence spectra were recorded in the UV, Vis, and NIR wavelength ranges. Judd-Ofelt (J-O) and free-ion parameters were computed based on the absorption band intensities and energy level positions. Utilizing the J-O parameters, various radiative parameters were determined for distinct excited states of Tm3+ ions in CFB glasses. Stimulated emission cross-sections (se) and effective bandwidths (Dleff) were calculated for the observed emission bands. The increase in Tm2O3 concentration resulted in an augmentation of emission peak intensities in the visible range, followed by a decline at higher concentrations. The quenching of emission intensities was attributed to energy transfer through cross-relaxation mechanisms. The NIR emission spectrum, excited by an 808 nm laser diode (LD), exhibited a peak at 1.47 mm corresponding to the 3H4-3F4 transition, with the intensity of the NIR emission peak increasing with the concentration of Tm2O3. Furthermore, Beer-Lambert and McCumber theories were applied to assess the absorption and emission cross-sections for the prominent 3F4–3H6 transition at the 1.82 mm emission wavelength.

Photoluminescence and energy transfer mechanisms of Tm3+ doped Y2O3 laser crystals: experimental and theoretical insights.

Rare-earth thulium (Tm3+) doped yttrium oxide (Y2O3) host single crystals are promising "eye-safe" laser materials. However, the mechanisms of photoluminescence and energy transfer in Tm3+ doped Y2O3 crystals are not yet understood at the fundamental level. Here, we synthetize a series of Y2O3:Tm3+ samples by the sol-gel method. Our experimental results show that the most intensive absorption line of the 3H6 → 1D2 transition occurs at 358 nm, and the strongest emission line of the 1D2 → 3F4 transition is located at 453 nm, which are in good agreement with the calculations of 363 nm and 458 nm, respectively. By using the CALYPSO structural search method, the ground state structure of Y2O3:Tm3+ with P2 space group symmetry is uncovered. The complete energy levels, including free-ion LS terms and crystal-field LSJ multiplet manifolds, of Y2O3:Tm3+ are obtained based on our developed WEPMD method. The present findings show that our WEPMD method can be used in experiments to elucidate the underlying mechanisms of photoluminescence and energy transfer in Tm3+ doped Y2O3 crystals, which offer insights for further understanding of other rare-earth doped laser materials.

Luminescence properties and energy transfer of Tm3+–Eu3+ double-doped LiLaSiO4 phosphors

A series of LiLaSiO4:yTm3+, zEu3+ phosphors were prepared by high-temperature solid-phase reaction. The microstructure, luminescence performance and quantum yield of the phosphors are characterized by XRD, SEM and fluorescence spectrometer. When the monitoring wavelength is 360 nm, LiLaSiO4:yTm3+ phosphors showed a sharp emission peak at 460 nm, corresponding to the 7F0 → 5D2 energy level transition, and the concentration quenching point of Tm3+ ions was y = 0.015. LiLaSiO4:yTm3+, zEu3+ phosphors have emission peaks of Tm3+ ions at 460 nm and Eu3+ ions at 618 nm, respectively. As the molar mass fraction of Eu3+ ions doped increase, the luminous intensity of Tm3+ ions gradually decrease, and the luminous intensity of Eu3+ ions increase first and then decrease, and the concentration quenching point of Eu3+ ions was z = 0.08. The energy transfers of Tm3+ → Eu3+ ions through electric dipole-electric dipole interactions are demonstrated by the luminous intensity variation law and fluorescence lifetime. By changing the doping ratio of Eu3+ and Tb3+ ions, the full-color control of the phosphor luminescent color from blue to red can be achieved.

White light generation and energy transfer in Tm3+/Tb3+/Sm3+ -doped 60TeO2. 40ZnO glasses

The Tm3+/Tb3+/Sm3+ doped 60TeO2·40ZnO glass were prepared and white light generation under 355 nm excitation were investigated. The glass samples were produced adjusting the ions concentrations in order to achieve the red-green-blue relative intensity ratios pursuing white light emission. The overall emission light chromaticity coordinates sweeped out the CIE-1931 color diagram. In addition, the emission spectra showed a decrease in Tm3+ emission intensity when Tb3+ and Sm3+ was added to the glass samples, suggesting energy transfer mechanisms. The decay lifetime data revealed the occurrence of a non-radiative energy transfer process from Tm3+ for both Tb3+ and Sm3+ ions. Accordingly, the results herein reported suggest that the 60TeO2·40ZnO glasses are viable as hosts for W-LED and SSL applications.

Enhanced red upconversion emission and energy transfer of Tm3+/Cr3+/Yb3+ tri-doped transparent fluorosilicate glass-ceramics

In this paper, the upconversion (UC) emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent fluorosilicate glass-ceramics (SGC) containing Ba2LaF7 nanocrystals were investigated. The enhancement of red UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent SGC were also investigated. Through the energy transfer processes between Cr3+ and Tm3+, and the combination of Cr3+-Tm3+ led to the red UC emission intensity of Tm3+/Cr3+/Yb3+ tri-doped transparent SGC bands centered at ~806 and ~858 nm has been significantly enhanced. The CIE chromaticity coordinates for UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SGC-0.2Tm1Cr2Yb transparent SGC sample is calculated (x = 0.704; y = 0.296) and the UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent SGC has been identified in red color region of CIE chromaticity coordinates. In addition, the ET processes between Cr3+ and Tm3+ are also proposed and discussed.

Preparation, luminescence properties and energy transfer of Tm3+ and Tm3+-Eu3+ doped glass-ceramics containing NaY(MoO4)2

A series of Tm3+ mono-doped and Tm3+-Eu3+ co-doped transparent glass-ceramics (GCs) containing NaY(MoO4)2 crystal phase was synthesized by melt quenching and glass crystallization. The optimal heat treatment condition, crystal structure, microscopic morphology, transmittance, luminescent properties and energy transfer of samples were studied using DSC, XRD, SEM, spectrophotometer and fluorescence spectrometer, respectively. When the Tm3+ mono-doped concentration is 0.4%, the emission intensity is the strongest at 456 ​nm due to 1D2→3F4 transition of Tm3+. Energy transfer from Tm3+ to Eu3+ is observed by fluorescence spectra of Tm3+-Eu3+ co-doped GCs, and the optimal doping concentrations of Tm3+ and Eu3+ are 0.4% and 1.3%, respectively. In addition, the Tm3+-Eu3+ co-doped GCs can achieve tunable emission from blue to purple by adjusting the doping concentration of Eu3+. These results indicate that Tm3+ mono-doped and Tm3+-Eu3+ co-doped GCs have potential applications in the field of color display.

The mid-infrared emission properties and energy transfer of Tm3+ /Er3+ co-doped tellurite glass pumped by 808/980nm laser diodes

The spectral performance of the Tm3+/Er3+ co-doped tellurite glass under the pump at 808/980 nm and the energy transfer process between Tm3+ and Er3+ were mainly studied. The mid infrared fluorescence spectra showed that when the concentration of doped Er3+ ion was 0.5mol%, the fluorescence intensity of 1.8 μm and 2.7 μm reached the peak. While at the pump of 980 nm, the maximum occurred in 1mol% of Er3+ ions. Under 808/980 nm pumping system, different energy transfer mechanisms between Tm3+ and Er3+ ions were accordingly proposed. The maximum emission cross section of 0.5 Tm3+/0.5Er3+ codoped sample can reach 4.68 × 10−21 cm2 at 1886 nm. When P was 0.4, the gain of Tm3+:3F4→3H6 at 1852–2100 nm started to be positive while its maximum gain coefficient was 0.91 cm−1, and its central wavelength was 1887 nm. Therefore, the large emission cross section and the high gain are conducive to the Tm3+/Er3+ co-doped tellurite glass to obtain low threshold value and high gain of the 2 μm laser output.

Luminescence and energy transfer of Tm3+ and Dy3+ co-doped Na3ScSi2O7 phosphors.

A series of Tm3+ and Dy3+ ions single- or co-doped Na3ScSi2O7 (NSSO) phosphors were prepared by a conventional solid state reaction method. The X-ray diffraction (XRD) patterns, photoluminescence (PL) properties, fluorescence decay curve and energy transfer behavior of the samples were studied. The XRD patterns show that all the diffraction peaks of the samples are consistent with the JCPDS standard data. Under UV excitation, the singly doped NSSO phosphors with Tm3+ and Dy3+ ions show blue and yellow characteristic emission. The emission color of NSSO:Tm3+,Dy3+ can be adjusted by the corresponding Tm3+–Dy3+ energy transfer. In addition, the chromaticity coordinate of NSSO:0.04Tm3+,0.13Dy3+ is (0.3195, 0.3214), which is close to the ideal white light (0.333, 0.33). These results show that NSSO:Tm3+,Dy3+ has potential application value in white light emitting diodes (WLEDs).

Tm3+/Tb3+/Eu3+掺杂硼酸盐玻璃陶瓷的能量转换和发光性能

Tm³⁺/Tb³⁺/Eu³⁺掺杂硼酸盐玻璃陶瓷的能量转换和发光性能

Luminescent properties and energy transfer of Tm3+/Dy3+ co-doped oxyfluoride borate glasses for white LEDs

Tm3+/Dy3+ co-doped oxyfluoride borate glasses with composition of 25CaF2–25ZnO–6P2O5–44B2O3 (mol%) for white light-emitting diodes were synthesized by a conventional melting-quenching method. The glass structure, spectroscopic properties and decay time profiles were characterized by XRD and FT-IR, optical and fluorescence spectrum measurements. Under 354 nm excitation, the color tones change from light blue (0.3004, 0.2646) to warm white (0.3626, 0.3642) by increasing concentration of Tm3+. The shortening of the Dy3+ emission decay time in presence of Tm3+ suggests that Dy3+/Tm3+ non-radiative energy transfer occurs. By using the Inokuti–Hirayama model, it is inferred that an electric quadrupole–quadrupole interaction might be the dominant mechanism involved in the energy transfer. The results suggest that the as-prepared Tm3+/Dy3+ co-doped oxyfluoride borate glasses may be promising candidate in white LEDs and other display devices.

Around 2 μm fluorescence and energy transfer in Tm3 +/Ho3 + co-doped tellurite glass

In this work, the near-infrared photoluminescence properties in Tm3+/Ho3+ co-doped tellurite glass was investigated. The tellurite glass with composition TeO2-ZnO-Na2O-La2O3 was synthesized using conventional melt-quenching technique and characterized by UV/Vis/NIR absorption and near-infrared emission spectroscopies, fluorescence decay measurement and differential scanning calorimeter (DSC) analysis. Under the excitation of 808nm laser diode (LD), a broadband 2.0μm band luminescence ranging from 1600 to 2200nm with a full width at half maximum (FWHM) of 362nm was observed, which was contributed by 1.85μm fluorescence from Tm3+: 3F4→3H6 and 2.05μm fluorescence from Ho3+: 5I7→5I8. The fluorescence emission of Ho3+ was originated from the energy transfer from Tm3+ to Ho3+ ions, and the energy transfer mechanism was elucidated by analyzing fluorescence decay behavior of Tm3+ and quantitative calculation of phonon contribution joined in the energy transfer process. Meanwhile, based on the absorption spectrum, some important spectroscopic parameters such as Judd-Ofelt intensity parameter, spontaneous radiative transition probability, fluorescence branching ratio, absorption and emission cross-sections, and gain coefficient spectrum were calculated to reveal the spectroscopic properties of doped tellurite glass. Furthermore, from the DSC curve it can be derived that the investigated glass possesses a good thermal stability with ΔT(=Tx−Tg) larger than 152°C. These results indicate that Tm3+/Ho3+ co-doped tellurite glass could be a promising gain medium applied for 2.0μm near-infrared band broad fiber amplifiers and tunable fiber lasers.

Luminescent characteristics of Tm3 +/Tb3 +/Eu3 + tri-doped phosphate transparent glass ceramics for white LEDs

Tm3+/Tb3+/Eu3+ tri-doped transparent glass ceramics (GCs) are obtained via melt-quenching technique and subsequent heating of glass with composition of 20Na2O-42ZnO-28P2O5-9B2O3-1Sb2O3 (mol%). XRD and TEM results demonstrate that orthorhombic NaZnPO4 nanocrystals (NCs) are precipitated among the glass matrix. Under 362nm excitation, the color tones of GCs change from light blue (0.3134, 0.3477) to warm white (0.3886, 0.3373) by altering concentration of Eu3+. The energy transfer of Tm3+→Eu3+ and Tb3+→Eu3+ is confirmed by photoluminescence spectra and fluorescence decay curves. The results indicate that the as-prepared Tm3+/Tb3+/Eu3+ co-doped GCs is a potential matrix material for white light-emitting diodes under UV-LED excitation.

Tunable luminescence mediated by energy transfer in Tm3+/Dy3+ co-doped phosphate glasses under UV excitation

Tm3+/Dy3+ co-doped phosphate glasses for white light-emitting diodes were synthesized by a conventional melting-quenching method. A spectroscopic research based on optical, photoluminescence spectrum and decay time curves in Tm3+/Dy3+ co-doped phosphate glasses was carried out. The color of luminescence could be tuned by altering the concentrations of Tm3+ ions. Under UV light excitation, the CIE chromaticity coordinates (0.3471, 0.3374) and color correlate temperature (CCT = 4866.21 K) close to the standard white-light illumination (0.333, 0.333 and CCT = 5454.12 K) could be achieved in 0.4 Tm3+/0.6 Dy3+ (mol %) co-doped glass sample. The decrease of the Dy3+ emission decay time in existence of Tm3+ ascertained that non-radiative energy transfer from Dy3+ to Tm3+ occurred. Moreover, the research of energy transfers between Dy3+ and Tm3+ based on the Inokuti-Hirayama model revealed that an electric quadrupole-quadrupole interaction might be the predominant mechanism participated in the energy transfer. This finding suggests that the as-prepared Tm3+/Dy3+ co-doped phosphate glasses may be promising candidate for white LEDs and other display devices.

Mid-infrared luminescence and energy transfer of Tm3+ in silicate glasses by codoping with Yb3+ ions

A kind of novel silicate glasses doped with Tm3+ sensitized by Yb3+ were prepared by conventional melt quenching method. The optical properties of the synthesized glasses were theoretically and experimentally investigated. Based on the absorption spectra and the Judd-Ofelt theory, the J-O intensity parameters (Ωt), radiative transition probability (400.4s−1), fluorescence lifetime (4.99ms) and absorption and emission cross sections (σe=2.51×10−20cm2) were calculated. According to fluorescence spectra, the 1.8μm emission of Tm3+ could be greatly enhanced by adding proper amount of Yb3+ under the excitation of 980nm and the optimized concentration ratio of Tm3+ and Yb3+ was found to be 1:3 in the present silicate glass system. Besides, the energy transfer mechanism between Yb3+ and Tm3+ were thoroughly discussed. With the assistance of Yb3+, the lifetime of Tm3+ from 0.54ms increased to 1.42ms. The energy transfer efficiency from Yb3+ to Tm3+ could reach 90.94%, and the energy transfer coefficient was 5.43×10−41cm6/s. The content of OH− was measured. The above results showed that Tm3+/Yb3+ co-doping could be expected to a promising way to achieve high efficient 2μm lasing pumped by a 980nm LD.