Temperature-dependent Luminescence Research Articles

Delineating Dy3+ and Sm3+ in thermally stable strontium silicate apatites for multifunctional applications

The structural, optical and temperature dependent luminescence properties of a series of Sr2Y8-xREx(SiO4)6O2 (RE=Dy and Sm) silicate phosphors are investigated for their multifunctional applications. The phosphors were synthesized using the solid-state reaction route with varying doping levels and characterized for phase purity. X-ray Diffraction analysis revealed the hexagonal crystal structure of (Sr2RE2)(RE6)(SiO4)6O2, indicating the incorporation of rare earth (RE) ions into two distinct crystallographic sites, thereby augmenting the luminescence properties. Dy3+ doped compounds exhibit intense yellow emission, promising white light generation when paired with InGaN blue LED chips. Sm3+ doped samples show orange-red emission around 601 nm, attributed to multipole-multipole interactions, with rapid decay curves suitable for high-speed response LEDs. Correlated Color Temperature (CCT) values were computed to assess the commercial viability of these phosphors in luminescence applications and the role of lighting in the growth of indoor plants and office spaces is discussed. The Sr2Y7.8Dy0.2(SiO4)6O2 phosphor with remarkable quantum yield of 63.56% demonstrated a thermal stability of 0.27 eV with enhanced sensitivity of about 0.39% K−1 and Sr2Y7.8Sm0.2(SiO4)6O2 with stability around 0.31eV with sensitivity of 1.11% K⁻¹ at 100K reveals them as potential candidates for optical temperature sensing. These results declare the competence of synthesized novel silicate apatites in solid-state lighting and optical thermometry.

Investigation of the luminescence properties and temperature dependent luminescence properties of Sm3+ doped NaPbBi2(PO4)3 orthophosphate phosphor: A promising candidate for light and light sensing applications

The red phosphor for light application is in high demand. In this regard, a series of orange-red phosphors, NaPbBi2(PO4)3: Sm3+, with a single phase were obtained by the conventional solid state reaction method. The X-ray diffraction (XRD) confirms that the phosphor belongs to the cubic structure with a space group I-43d (220). The optical property of the phosphor was studied through the diffuse reflectance spectroscopy measurements and the characteristic peaks of the Sm3+ ions were identified. Exciting the phosphors at 404 nm, produced a strong orange-red emission at 601 nm. The optimum concentration of the phosphor was found to be 0.03 mol. In all emission transitions of the Sm3+ ions within the host lattice, the energy transfer (ET) occurs among the nearest neighbour ions. The lifetime values were in the order of milliseconds. The photometric parameters revealed that the emission lies in the orange-red region with color coordinates (0.5863, 0.4129) and a color purity of 99.4 %. The temperature dependent luminescence properties of the phosphor were also investigated and all these results showed that the phosphor could serve as a good candidate for light/light sensing applications.

Construction of a Zn(II)-Eu(III) Nanoring with Temperature-Dependent Luminescence for the Qualitative and Quantitative Detection of Neopterin as an Inflammatory Marker.

A nine-metal Zn(II)-Eu(III) nanoring 1 with a diameter of about 2.3 nm was constructed by the use of a long-chain Schiff base ligand. It shows a luminescence response to neopterin (Neo) through the enhancement of lanthanide emission with high selectivity and sensitivity, which can be used to quantitatively analyze the concentrations of Neo in fetal calf serum and urine. The luminescence sensing of 1 to Neo is temperature-dependent, and it displays more obvious response behavior at lower temperatures. Filter paper strips bearing 1 can be used to qualitatively detect Neo by the color change from chartreuse to red under a UV lamp. The limit of detection is as low as 3.77 × 10-2 nM.

Trivalent dysprosium activated LaSr2AlO5 nanophosphors for NUV-excited wLEDs: Insights into structural, optical, Judd-Ofelt parameters and temperature dependent photoluminescence

Gel-combustion (GC) methodology was implemented in the present research to produce a series of single phase Dy3+ doped LaSr2AlO5 nanophosphors for the usage in wLEDs. X-ray powder diffraction patterns verified the phase purity and crystal structure of the produced materials. The XRD inspection supported the successful fabrication of tetragonal structured (I4/mcm space group) phosphors and revealed good accordance with card number 70–2197 on the JCPDS database. We collected diffuse reflectance spectra (DRS) to examine how doping affects the band gap. Furthermore, energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM) have been employed for assessing elemental composition and surface morphology. On 349 nm excitation, LaSr2AlO5:Dy3+ phosphors produce the distinctive yellow PL emissions causedby 4F9/2→6H13/2 transition. Using excitation spectra, the Judd-Ofelt (J-O) characteristic (Ω = 2, 4, 6) have been determined. The Dy3+ transition's features show that the J-O parameters followed the trend which suggested an asymmetric environment around the ligand. The electric dipole transition predominated in the luminescence spectrum, causing the LaSr2AlO5:Dy3+ phosphor to emit a yellowish whitecolor. The fundamental mechanism for the energy transfer and concentration quenching instances among activator ions was discovered to be dipole-quadrupole interactions. Temperature dependent luminescence showed that the synthesized phosphors had thermal stability up to 523 K with activation energy of 0.1312 eV. The future prospects of the synthesized phosphor as an effective choice for near-ultraviolet-activated wLEDs are substantially supported by current comprehensive research.

Spectroscopic studies of TeO2-based glasses doped with Sm3+ and its use as an optical temperature sensor

This study reports the synthesis and characterization of glasses in the (100-x)65TeO2-15Li2O-20ZnO + xSm2O3 system doped with Sm2O3, denoted as Sm3+: TLZ glasses, with varying doping concentrations from 0.1, 0.15, 0.2, 0.35, 0.5, and 1 mol%. The structural and optical properties, as well as the temperature dependence of luminescence, were investigated. Excitation at 405nm resulted in strong orange-red luminescence at 566, 600, and 646 nm. The local environment surrounding Sm3+ ions was explored using the intensity ratio of electric and magnetic dipole transitions. The non-radiative energy transfer between neighboring Sm3+ ions was evaluated using the Inokuti-Hirayama model, allowing for the determination of the critical transfer distance. The temperature dependence of luminescence, displayed by Commission Internationale de L’Eclairage (CIE) chromaticity coordinates, exhibited a monotonic change from (0.611, 0.387) at 295 K to (0.605, 0.393) at 479 K. The Sm3+:TLZ glasses doped with 0.15 mol% showed the highest relative thermal sensitivity of 0.10%K-1 at 479 K, suggesting their potential as luminescent thermometers.

Interrupting the long-range energy migration among Eu3+ by the introduction of unequivalent [NaO8] units to achieve both high quenching concentration and quantum yield in NaY2Ga2InGe2O12

In the pursuit of optimizing white light-emitting diodes (WLEDs), Eu3+-doped phosphors have emerged as a key component in strategies that combine ultraviolet (UV) LED chips with red, green, and blue (RGB) tricolor phosphors. However, their application has been notably constrained by concentration quenching and thermal quenching. To address this challenge, we have developed a series of novel red phosphors, NaY2-xGa2InGe2O12:xEu3+. The powder X-ray diffraction (XRD) indicates that the NaY2Ga2InGe2O12(NYGIG) belongs to the garnet family. The [NaO8] unit replaces one-third of the eight-coordinated sites of garnet and leaves the other two-thirds for the [YO8], which helps to prevent long-range energy migration among Eu3+ especially when the eight-coordinated sites were highly substituted. Such a structure feature allowed the NaY2-xGa2InGe2O12:xEu3+ phosphor to achieve an optimal quantum yield of 95.6% at an extremely high Eu3+ doping x value up to 1.2. Moreover, further studies on the temperature-dependent luminescence spectra confirm that an anomalous thermal quenching phenomenon will occur when the NaY2-xGa2InGe2O12:1.2Eu3+ phosphor is properly excited. In application, the combination of the red-emitting NaY2-xGa2InGe2O12:1.2Eu3+, blue-emitting BaMgAl10O17:Eu2+, and green-emitting Zn2SiO4:Mn2+ phosphors can realize high color rendering (CRI∼93) white light with the with CIE coordinates of (0.353,0.350), indicating that the NYGIG:Eu3+ phosphor own a promising potential for WLEDs.

Giant thermal enhancement of upconversion photoluminescence in Y2W3O12:Nd phosphor under 808 nm excitation

Luminescent materials usually suffer from thermal quenching at high temperature due to the aggravation of nonradiation relaxations. Herein, a giant enhancement of up conversion (UC) luminescence is observed in negative thermal expansion (NTE) Y2W3O12:Nd phosphor upon increasing the temperature from 310 to 790 K. In addition, the temperature-dependent UC emission is reversible. To penetrate into the mechanisms, the temperature-dependent luminescence intensity and lifetime are investigated for Nd doped negative and positive thermal expansion (PTE) phosphors. Based these investigation, we infer that the underlying mechanism of the giant enhancement for Y2W3O12:Nd phosphor are due to combined effects of phonon assisted absorptions and contraction of NTE crystals. Moreover, the observation of temperature-dependent near-infrared spectra (NIR) can support the mechanism from the other side. The present findings pave the way to overcome thermal quenching of Nd3+ ions and explore new thermal enhancement materials sensitized by Nd3+ ions.

Unlocking the luminescent potential of Pr3+/Yb3+ Co-doped Y2Mo4O15 for advanced thermometry applications

In this study, Pr3+/Yb3+ co-doped Y2Mo4O15 phosphor was successfully synthesized using the traditional citric acid-assisted sol-gel method, with the aim of exploring its potential for optical thermometry applications. The structural and morphological characteristics of the synthesized sample were comprehensively analyzed through X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Photoluminescence and temperature-dependent luminescence properties were systematically investigated within a temperature range of 298 K to 508 K, employing 473 nm excitation. To assess the temperature sensing capabilities of the phosphors, we utilized both the fluorescence intensity ratio (FIR) and fluorescence lifetime (FL) techniques. Optical temperature measurements were conducted through both thermal and non-thermal coupling methods. Our findings revealed that the FIR (I547/I490) exhibited an outstanding maximum sensitivity of 1.27% K−1, accompanied by remarkably low-temperature uncertainty (δT) values ranging from 0.04 to 0.83 K. This outstanding performance makes it the optimal choice for temperature sensing. Additionally, when employing FL thermometry, the maximum sensitivity (Sr) was determined to be 0.21% K−1 at 538 K. These results strongly indicate the significant potential of Y2Mo4O15: Pr3+/Yb3+ in the realm of optical thermometry, offering promising opportunities for precise and reliable temperature measurements.

White light-emitting ZnO:Dy3+ nanophosphors: delving into the spectroscopic parameters via Judd-Ofelt analysis.

Developing a single-phase white emitting nanophosphor with high quantum efficiency has become a hotspot for scientific world. Herein, single-phase white-light emitting Zn1-xO:xDy3+ nanophosphors have been synthesized via a sonochemical method. X-ray diffraction analysis and Raman spectroscopy-based investigations confirmed the hexagonal wurtzite phase for Zn1-xO:xDy3+ nanophosphors with preferential growth along the (101) plane. Scanning electron microscopy images showed the formation of a ribbon-shaped morphology with a diameter of ∼25 nm. The emission spectra of the Dy3+-activated ZnO nanophosphors exhibited three distinct peaks, namely blue (480 nm), yellow (572 nm), and red (635 nm) emissions, under near-UV excitations related to the 4F9/2 → 6HJ (J = 15/2, 13/2, and 11/2) transitions of Dy3+ ions. The values of CIE chromaticity coordinates for the optimized phosphor (x = 0.329, y = 0.334) with correlated color temperature (CCT) of 5657 K indicated cool white-light emission from the phosphor. The thermal stability of ZnO:Dy3+ nanophosphors was probed by temperature-dependent luminescence. Quantitative evaluation of Judd-Ofelt intensity parameters, radiative parameters, luminescence decay, and quantum efficiency of Zn1-xO:xDy3+ using the J-O theory suggests that these nanophosphors are promising luminescent media for commercial white LEDs and other display devices.

Temperature and pressure dependent luminescence mechanism of a zinc blende structured ZnS:Mn nanophosphor under UV excitation

Presenting a novel insight into Mn2+ luminescence processes in the ZnS nanophosphor and revealing its unique high-pressure luminescence decay behaviour and self-powered mechanoluminescence.

Strong green upconversion emission from submicron spindle-shaped SrMoO4:Yb3+,Er3.

Upconversion luminescence (UCL) is a fluorescence process where two or more lower-energy photons convert into a higher-energy photon. Lanthanide (Ln3+)-doped UCL materials often suffer from weak luminescence, especially when directly synthesized by a hydrothermal (HT) process due to the existing hydroxyl group and undesirable arrangement of dopants within host lattices which quench luminescence and limit energy transfer. Therefore, additional heat treatment processes are required to enhance their UCL emission, even though direct hydrothermal synthesis without further heat treatment has the advantages of low energy consumption, fast synthesis, and wide applicability to generate UCL materials. In this study, via a HT process without annealing, we have produced Yb3+ and Er3+ co-doped SrMoO4 submicron spindles with a strong green UCL emission which can be seen with the naked eye, which HT produced oxide-based UCL materials often fail to demonstrate. We have investigated different HT synthesis conditions, such as temperature, time, pH and dopant composition, which control the nucleation, growth, lattice structure arrangement, and ultimately their UCL properties through XRD, SEM, EDS and UCL measurements. The bright green UCL from the SrMoO4:Yb,Er submicron spindles is further enhanced by post-synthesis annealing within a molten NaNO3/KNO3 system to prevent particle size growth. The green UCL intensity from the annealed SrMoO4:Yb,Er submicron spindles surpasses samples produced by the solid-state method and is comparable to that from the commercial NaYF4:Yb,Er sample. We have further studied the temperature-dependent luminescence of both the HT-prepared and molten-salt annealed SrMoO4:Yb,Er submicron spindle samples. The strong UCL from our SrMoO4:Yb,Er submicron spindles could warrant their candidacy for bioimaging and anticounterfeiting applications.

Excitation wavelength and pumping power dependent temperature sensing property of Nd3+/Yb3+/Er3+ triply-doped LaNbO4 phosphor

Optical thermometry based on the fluorescence intensity ratio technology between the thermally coupled energy levels of Er3+ has become a research hotspot, but it is often limited by excitation conditions, which reduces its universality and reliability. In this work, Nd3+/Yb3+/Er3+ triply-doped LaNbO4 phosphor with excellent up-conversion (UC) luminescence characteristic and reliable temperature sensing sensitivity has been prepared by solid-state reaction method. Intense green and weak red UC emissions were gained under 808 nm and 980 nm excitations. The temperature dependent UC luminescence property and temperature sensing behavior of the sample has been investigated. The results demonstrated that the intensity ratio of the two green emissions was insensitive to the excitation wavelength and pumping power of the lasers, and the maximum absolute sensitivity was derived to be 0.91 % K−1 at 481 K. This work provides a new material with reliable and high temperature sensing sensitivity for optical thermometers.

Near UV-photons excited highly pure and thermally stable Ca2B2O5: Sm3+ phosphor for filling the amber gap

Un-doped and a series of Sm3+ ion-doped orange-red emitting Ca2(1-x)B2O5:2xSm3+ (x = 0.005–0.025 mol) phosphors were synthesized and explored for their potential to fill the amber gap. Structural, thermal, spectral, luminescence, and temperature-dependent luminescence studies of the obtained phosphors were carried out to investigate the synthesized phosphors. The powder X-ray diffraction and Rietveld refinement results confirmed the formation of the monoclinic phase of Ca2B2O5. The room temperature photoluminescence study revealed that under 405 nm excitation, the prepared phosphor shows four characteristic emissions due to the 4f-4f transitions i.e.4G5/2 → 6H5/2 (568 nm), 6H7/2 (607 nm), 6H9/2 (650 nm) and 6H11/2 (712 nm). The color purity of the prepared phosphors was determined to be 97.7 % with the Commission International de l'Eclairage coordinates of (0.60, 0.40) that correspond to a strong orange-red emission located in the amber gap. Moreover, temperature-dependent luminescence studies depicted that the phosphor is highly stable, at 150 ℃ retaining 89 % of its luminescence intensity compared to room temperature. The thermal stability was further verified by thermogravimetric analysis of the phosphors which revealed high thermal stability with no weight loss upto 900 ℃. The quantum yield was determined on prepared samples and found to be 84.25 %. Thus, the promising experimental result suggests that the extremely stable orange-red emitting Ca2B2O5:Sm3+ phosphor can be a potential choice to fill the amber gap in light-emitting diodes.

The Effect of Lu3+ Doping on the Structural Stability and Luminescence Performances of Gd3Al5O12:Dy Phosphors

Transparent ceramics (Gd0.975−xLuxDy0.025)3Al5O12 (x = 0.2, 0.5, 0.975) are fabricated by vacuum sintering with the transmittance of ~60% at 583 nm. The doping of Lu3+ was beneficial to stabilize the garnet phase, and the best doping concentration was 20 at.%. All three (Gd, Lu)3Al5O12:Dy ceramics display typical Dy3+ emission, originating from 4F9/2 → 6HJ (J = 15/2, 13/2, 11/2) transition. Temperature-dependent luminescence spectra from 303.15 K to 603.15 K prove that the (Gd, Lu)3Al5O12:Dy ceramics had good thermal stability and could be an ideal yellow-emitting candidate in light-emitting diodes. The luminous efficiency of the encapsulated white LED lamp was found to be ~87.9 lm/W when the injection current was 600 mA. The transparent (Gd, Lu)3Al5O12:Dy ceramics show great application potential in various optical systems especially in the fields of luminescence and display.

Near-infrared luminescent properties and applications of Fe3+-doped YAG phosphors

This study employed the high-temperature solid-phase method to successfully synthesize a comprehensive range of Y3Al12O5: xFe3+ novel near-infrared (NIR) phosphors based on yttrium aluminum garnet material. The samples were subjected to characterization utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy, first-principles calculations, excitation and emission spectroscopy, as well as temperature-dependent luminescence intensity analysis. Subsequently, the specimens were encapsulated within light-emitting diodes (LED) to facilitate their application in night vision and biometric sensing. The results revealed that all sintered samples were phase-pure, with particle sizes around 0.6 μm, exhibiting uniform and fully developed morphology. The absorption spectroscopy indicated a decrease in the bandgap with increasing Fe3+ doping concentration. The first-principles results revealed that the doping of Fe3+ introduces Fe-d orbitals, and their contribution to the conduction bands is nearly comparable to that of the d orbitals of the Y3+. The spectroscopic results indicated that the samples can be excited through charge transfer of O2− → Fe3+, leading to near-infrared emission at 784 nm with a full width at half maximum (FWHM) of 77 nm at 280 nm, and the FWHM is 73 nm under excitation at 411 nm. The thermal stability analysis revealed that as the temperature increased, there was no observed redshift or blueshift in the emission spectra. The encapsulated NIR LED allows clear visibility of blood vessels on the hand and cacti in a dark room environment. All the aforementioned results provide substantial evidence for the significant application potential of Y3Al12O5: xFe3+ NIR phosphors in biometric sensing and night vision.

Importance of evaluating the excitation intensity dependence of the temperature-dependent luminescence: Impact on optical thermometry and anti-thermal quenching performance

Afterglow materials exhibit distinct temperature-dependent luminescence compared to general optical materials due to the presence of extra unique energy transfer paths from traps to luminescent centers. These paths include: 1) energy transfer through the conduction band (CB), and 2) energy transfer via quantum tunneling channels to various energy levels. These have a notable impact on both the overall intensity and the relative intensity of emission at different temperatures, which is often unintentionally overlooked. To investigate the influence of these additional paths on temperature-dependent luminescence, we employed a simple yet effective method of varying the excitation light intensity in Y2CaSnGa4O12:Pr3+, an afterglow material. And the influences on optical thermometer and anti-thermal quenching performance were illustrated comprehensively. We ultimately arrived at some interesting and widespread conclusions: 1) The performance of fluorescence intensity ratio (FIR) thermometry, which relies on excitation intensity, can be stabilized by avoiding the presence of charging traps. The high sensitivity of the afterglow intensity ratio (AIR)-based thermometry, which does not require an external light source, may be closely associated with the quantum tunneling process. 2) The performance of trap-assisted anti-thermal quenching is excitation intensity-dependent. We elucidated the specific contribution of traps that had previously been unaccounted for in earlier reports.

Influence of plasmonic and thermo-optical effects of silver nanoparticles on near-infrared optical thermometry in Nd3+-doped TeO2–ZnO glasses

Optical thermometers based on the luminescence of trivalent rare earth-doped materials are often explored due to their high sensitivity and performance in the visible and infrared spectral regions. Among them, Nd3+ ions are widely used because they operate efficiently in the main biological windows, although an increase in their sensitivity at low temperatures is still desired. This work aims to investigate the influence of the addition of silver nanoparticles (Ag-NPs) on the temperature-dependent luminescence of Nd3+ doped TeO2–ZnO glasses over wide temperature ranges (295–480 K). The study shows that the plasmonic effects induced by Ag-NPs lead to an absolute sensitivity increase of up to ∼28.6% in Nd3+-based thermometers operating through a set of three thermally coupled energy levels. In addition, thermometry studies using high-power excitation beams reveal that the thermo-optical properties of Ag-NPs favor optical thermometer sensitivity enhancement due to local heating effects and compensates for the losses caused by luminescence quenching at high concentration of Nd3+ ions. Moreover, an experiment analyzing the speckle patterns generated by Nd3+ doped TeO2–ZnO glasses, conducted for the first time to the best of our knowledge, confirms the influence of the thermo-optical effects of Ag-NPs in optimizing the sensitivity of optical thermometers.

Origin of Eu2+/Eu3+ dual-fluorescence emission with temperature-dependency in borate glass containing Ca/SrAl2O4 crystals

At present, due to the existent trap levels, the investigation of the dual-fluorescence emission with temperature-dependency of Eu2+ and Eu3+ in long afterglow materials needs to be supplemented. In this work, Eu2+ and Eu3+ co-doped borate glass materials containing Ca/SrAl2O4 crystals are successfully prepared though solid phase melting method, presenting a temperature-dependent fluorescence emission changing from blue-violet to red-orange between 300 and 500K. This interesting finding is proved to be the different thermal quenching behavior caused by the varied luminescence transition mode of Eu2+ (440 nm) and Eu3+ (614 nm). Further, the instantaneous and the delayed trap carriers release is demonstrated to moderate the thermal quenching behavior, leading to better sensing performance at high temperatures in sample of more trap distribution, with Sr(max) being 1.3535% K−1 at 483K. Finally, good thermal cycling reversibility of the material shows that the temperature-dependent luminescence of Eu2+/Eu3+ assisted by traps is potential for optimizing the application of temperature sensing.

High thermal stability of warm white emitting single phase GdPO4: Dy3+/ Sm3+ phosphor for UV excited wLEDs

Highly thermally stable warm white light emission has been obtained from a single component phosphor; GdPO4: Dy3+/Sm3+. A series of GdPO4: Sm3+ (1%)/Dy3+ (x%) (x = 0.1, 0.5, 1 and 2) phosphors have been synthesized by the co-precipitation method. The crystal structure and phase purity of the samples obtained were verified by X-ray diffraction. Photoluminescence spectra, luminescence lifetimes are used to study the effect of Dy3+ concentration and the energy transfer from Dy3+ to Sm3+ as a function of excitation wavelength. The nearest-neighbor contributed to the non-radiative energy transfer from Dy3+ to Sm3+ in GdPO4, under 273 and 363 nm excitation. A warm white light was obtained from all phosphors excited at 273 nm and for 1 and 2% of Dy3+ in GdPO4:Sm3+ under 363 nm excitation. Temperature-dependent luminescence properties are determined for GdPO4: Sm3+ (1%), Dy3+ (1%) under 273 nm and 363 nm excitation. The studied phosphor has a good luminescence thermal stability and the determined activation energy for thermal quenching is 1.26 and 0.75 eV for 273 nm and 363 nm excitation wavelengths, respectively. The effect of the Dy3+ concentration as an activator ion responsible for the white emission light, at a fixed concentration of Sm3+ as a red emission compensator in the Dy3+ emission spectrum, was discussed. The low color temperature and high thermal stability indicate that the studied material is a promising solid-state emitting phosphors for the UV chip excited warm wLED applications.

Tailoring near-infrared luminescence with Er3+/Tm3+/Yb3+ tri-doped tellurite glasses for applications in the C, L and U bands

In this work, co-doped and tri-doped systems with Er3+, Tm3+ and Yb3+ were evaluated in tungsten-tellurite glasses to extend the amplification range of current Erbium-Doped Fiber Amplifiers (EDFAs). The conditions of synthesis showed that the use of appropriate atmosphere was efficient to decrease the OH content and enhance the Er3+ emission. Spectroscopic studies on Er3+ and Tm3+ co-doped glasses revealed an emission from 1500 to 2000 nm with the energy transfer between both ions and the luminescence from Er3+: 4I13/2 → 4I15/2 and Tm3+:3F4 → 4H6. The addition of Yb3+ increased around 4 times in the NIR luminescence at 1535 nm. Lifetime measurements showed an increase of energy transfer efficiency (η) from Er3+ to Tm3+ as Tm2O3 content increased. In addition, temperature-dependent luminescence is studied for co-doped and tri-doped systems in the range of −180 to 75 °C. As temperature decreases, the ratio between Er3+ and Tm3+ emissions increases whereas the introduction of Yb3+ considerably enhanced the emission from Er3+ at 1535 nm related to Tm3+. This study demonstrates that the NIR emission of these tellurite glasses, both in intensity and bandwidth, can be considerably tailored by means of the dopant content, synthesis conditions, and temperature.