Scintillation of Sol–Gel Derived Lutetium Orthoborate Doped with Ce3+ Ions

Ce^{3 +}-doped LuBO₃ powders have been prepared by a sol–gel process with Ce^{3 +} concentration varying between 0 and 5 mol%. These materials have been analyzed by X-ray Diffraction and Fourier Transform Infra Red Spectroscopy. The results confirm that all the materials have the vaterite type even if the calcination has been performed at 800°C. Furthermore, doping with Ce^{3 +} ions does not affect the structure and the vaterite is preserved even at 5% doping. Scanning Electron Microscopy showed a very uniform morphology with small spherical grains with a narrow size distribution. Optical properties have been studied to confirm the effective substitution of Ce^{3 +} for Lu^{3 +} ions and to determine the materials scintillation performances. It has been shown that 0.5% is the optimum Ce(III) concentration in term of scintillation yield with an X-ray conversion yield equivalent to that of standard BGO (Bi₄Ge₃O₁₂). The afterglow has also been measured and confirms the potential of these materials as scintillators.     

Pseudo-2D Layered Organic-Inorganic Manganese Bromide with a Near-Unity Photoluminescence Quantum Yield for White Light-Emitting Diode and X-Ray Scintillator

Eco-friendly lead-free organic–inorganic manganese halides (OIMHs) have attracted considerable attention in various optoelectronic applications because of their superior optical properties and flexible solution processibility. Herein, we report a novel pseudo-2D layered OIMH (MTP)₂MnBr₄ (MTP: methyltriphenylphosphonium), which exhibits intense green emission under UV/blue or X-ray excitation, with a near-unity photoluminescence quantum yield, high resistance to thermal quenching (I_{150 °C}=84.1 %) and good photochemical stability. These features enable (MTP)₂MnBr₄ as an efficient green phosphor for blue-converted white light-emitting diodes, demonstrating a commercial-level luminous efficiency of 101 lm W⁻¹ and a wide color gamut of 116 % NTSC. Moreover, these (MTP)₂MnBr₄ crystals showcase outstanding X-ray scintillation properties, delivering a light yield of 67000 photon MeV⁻¹, a detection limit of 82.4 nGy s⁻¹, and a competitive spatial resolution of 6.2 lp mm⁻¹ for X-ray imaging. This work presents a new avenue for the exploration of eco-friendly luminescent OIMHs towards multifunctional light-emitting applications.     

Preparation of N-acetyl-para-aminophenol via a flow route of a clean amination and acylation of p-nitrophenol catalyzing by core-shell Cu2O@CeO2

The selectivity and reactivity to converse series nitroaromatic into aminobenzenes are especially significant, which play a vital role in synthesizing required drugs or other fine chemicals. Herein, p-nitrophenol (p-NP) has been completely conversed into p-anomiphenol (p-AP) with a high activity factor k (0.033 s⁻¹·mg⁻¹) and reusability by core-shell Cu₂O@CeO₂ catalyst. N-acetyl-para-aminophenol (paracetamal, APAP) as a model drug was further synthesized via a flow route proceeded in two steps including p-NP reduction and subsequently p-AP acylation with self-constructing device. The yield of the paracetamal is up to 85% with a highly purity. The mechanism investigation justifies the rich-electron centers and cation defects generated from the redox coupled Cu⁺→Cu⁰ with Ce³⁺→Ce⁴⁺ will steer selective conversion of p-NP to p-AP, a rate-determining step in the production of APAP. The present results could visualize a highly selective catalyst and a new synthesis route for pharmaceuticals such as paracetamal by using nitroaromatic compounds as the raw materials with environment-friendly, low-cost, easy-manipulation, high-efficiency and high purity.     

High Performance Dynamic X-ray Flexible Imaging Realized Using a Copper Iodide Cluster-Based MOF Microcrystal Scintillator

X-ray imaging technology has achieved important applications in many fields and has attracted extensive attentions. Dynamic X-ray flexible imaging for the real-time observation of the internal structure of complex materials is the most challenging type of X-ray imaging technology, which requires high-performance X-ray scintillators with high X-ray excited luminescence (XEL) efficiency as well as excellent processibility and stability. Here, a macrocyclic bridging ligand with aggregation-induced emission (AIE) feature was introduced for constructing a copper iodide cluster-based metal–organic framework (MOF) scintillator. This strategy endows the scintillator with high XEL efficiency and excellent chemical stability. Moreover, a regular rod-like microcrystal was prepared through the addition of polyvinyl pyrrolidone during the in situ synthesis process, which further enhanced the XEL and processibility of the scintillator. The microcrystal was used for the preparation of a scintillator screen with excellent flexibility and stability, which can be used for high-performance X-ray imaging in extremely humid environments. Furthermore, dynamic X-ray flexible imaging was realized for the first time. The internal structure of flexible objects was observed in real time with an ultrahigh resolution of 20 LP mm⁻¹.     

Dimensional and Optoelectronic Tuning of Lead-free Perovskite Cs3Bi2I9−nBrn Single Crystals for Enhanced Hard X-ray Detection

Inorganic Bi-based perovskites have shown great potential in X-ray detection for their large absorption to X-rays, diverse low-dimensional structures, and eco-friendliness without toxic metals. However, they suffer from poor carrier transport properties compared to Pb-based perovskites. Here, we propose a mixed-halogen strategy to tune the structural dimensions and optoelectronic properties of Cs₃Bi₂I_9−nBr_n (0≤n≤9). Ten centimeter-sized single crystals are successfully grown by the Bridgman technique. Upon doping bromine to zero-dimensional Cs₃Bi₂I₉, the crystal transforms into a two-dimensional structure as the bromine content reaches Cs₃Bi₂I₈Br. Correspondingly, the optoelectronic properties are adjusted. Among these crystals, Cs₃Bi₂I₈Br exhibits negligible ion migration, moderate resistivity, and the best carrier transport capability. The sensitivities in 100 keV hard X-ray detection are 1.33×10⁴ and 1.74×10⁴ μC Gy_air⁻¹ cm⁻² at room temperature and 75 °C, respectively, which are the highest among all reported bismuth perovskites. Moreover, the lowest detection limit of 28.6 nGy_air s⁻¹ and ultralow dark current drift of 9.12×10⁻⁹ nA cm⁻¹ s⁻¹ V⁻¹ are obtained owing to the high ionic activation energy. Our work demonstrates that Br incorporation is an effective strategy to enhance the X-ray detection performance by tuning the dimensional and optoelectronic properties.     

Highly Effective Hybrid Copper(I) Iodide Cluster Emitter with Negative Thermal Quenched Phosphorescence for X-Ray Imaging

The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)₄Cu₄I₄ , where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra-bright triplet yellow-orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon-assisted de-trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X-ray imaging. The (DBA)₄Cu₄I₄ wafer demonstrates a light yield higher than 10⁴ photons MeV⁻¹ and a high spatial resolution of ≈5.0 lp mm⁻¹, showing great potential in practical X-ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.     

Hydrothermal synthesis of core-shell structured PS@GdPO<Subscript>4</Subscript>:Tb<Superscript>3+</Superscript>/Ce<Superscript>3+</Superscript> spherical particles and their luminescence properties

Non-aggregated spherical polystyrene (PS) particles were coated with GdPO₄:Tb³⁺/Ce³⁺ phosphor layers by a conventional hydrothermal synthesis using poly(vinylpyrrolidone) (PVP) as an additive without further annealing treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), as well as luminescence decay experiments were used to characterise the resulting core-shell structured PS@GdPO₄:Tb³⁺/Ce³⁺ samples. The results of XRD indicated that the PS particles were successfully coated with the GdPO₄:Tb³⁺/Ce³⁺ phosphor layers, which could be further verified by the images of FESEM. Under ultraviolet excitation, the PS@GdPO₄:Tb³⁺/Ce³⁺ phosphors show Tb³⁺ characteristic emission, i.e. ⁵D₄-⁷F_J (J = {6, 5, 4, 3}) emission lines with green emission ⁵D₄-⁷F₅ (543 nm) as the most prominent group. The core-shell phosphors so obtained have potential applications in field emission display (FED) and plasma display panels (PDP).     

Low Bandgap 2D Perovskite Single Crystal with Anomalous-large Charges/ions Collection Ratio for Ultra-sensitive and Stable X-ray Detectors

The low-dimensional halide perovskites have attracted increasing attention due to their improved moisture stability, reduced defects, and suppressed ions migration in many optoelectronic devices such as solar cells, light-emitting diodes, X-ray detectors, and so on. However, they are still limited by their large band gap and short charge carriers’ diffusion length. Here, we demonstrate that the introduction of metal ions into organic interlayers of two-dimensional (2D) perovskite by cross-linking the copper paddle-wheel cluster-based lead bromide ([Cu(O₂C−(CH₂)₃−NH₃)₂]PbBr₄) perovskite single crystals with coordination bonds can not only significantly reduce the perovskite band gap to 0.96 eV to boost the X-ray induced charge carriers, but can also selectively improve the charge carriers’ transport along the out-of-plane direction and blocking the ions motion paths. The [Cu(O₂C−(CH₂)₃−NH₃)₂]PbBr₄ single-crystal device can reach a record charges/ions collection ratio of 1.69×10¹⁸±4.7 % μGy_air⁻¹ s, and exhibit a large sensitivity of 1.14×10⁵±7% μC Gy_air⁻¹ cm⁻² with the lowest detectable dose rate of 56 nGy_air s⁻¹ under 120 keV X-rays irradiation. In addition, [Cu(O₂C−(CH₂)₃−NH₃)₂]PbBr₄ single-crystal detector exposed to the air without any encapsulation shows excellent X-ray imaging capability with long-term operational stability without any attenuation of 120 days.     

Synthesis, structure and X-ray excited luminescence of Ce-doped AREP2O7-type alkali rare earth diphosphates (A=Na, K, Rb, Cs; RE=Y, Lu)

The crystal structures of five new alkali rare earth diphosphates were obtained by Rietveld refinement of powder X-ray diffraction (XRD) profiles, including four alkali lutetium diphosphates ALuP₂O₇ (A=Na, K, Rb, Cs) and the low temperature phase of KYP₂O₇. The scintillation properties of Ce³⁺-doped AREP₂O₇ (A=Na, K, Rb, Cs; RE=Y, Lu) powder samples were studied under static and pulsed X-ray excitations, and featured outstanding scintillation properties with light yields 1–2 times of that of Bi₄(GeO₄)₃ and relatively short decay time of 20–28 ns. Considering the suitable emission wavelength range, large light yield, short decay time, and non-hygroscopic nature, Ce³⁺-doped AREP₂O₇-type alkali rare earth diphosphates are potential candidates for high-counting-rate scintillation applications.     

Understanding the Synergy between Fe and Mo Sites in the Nitrate Reduction Reaction on a Bio-Inspired Bimetallic MXene Electrocatalyst

Mo- and Fe-containing enzymes catalyze the reduction of nitrate and nitrite ions in nature. Inspired by this activity, we study here the nitrate reduction reaction (NO₃RR) catalyzed by an Fe-substituted two-dimensional molybdenum carbide of the MXene family, viz., Mo₂CT_x : Fe (T_x are oxo, hydroxy and fluoro surface termination groups). Mo₂CT_x : Fe contains isolated Fe sites in Mo positions of the host MXene (Mo₂CT_x) and features a Faradaic efficiency (FE) and an NH₃ yield rate of 41 % and 3.2 μmol h⁻¹ mg⁻¹, respectively, for the reduction of NO₃⁻ to NH₄⁺ in acidic media and 70 % and 12.9 μmol h⁻¹ mg⁻¹ in neutral media. Regardless of the media, Mo₂CT_x : Fe outperforms monometallic Mo₂CT_x owing to a more facile reductive defunctionalization of T_x groups, as evidenced by in situ X-ray absorption spectroscopy (Mo K-edge). After surface reduction, a T_x vacancy site binds a nitrate ion that subsequently fills the vacancy site with O* via oxygen transfer. Density function theory calculations provide further evidence that Fe sites promote the formation of surface O vacancies, which are identified as active sites and that function in NO₃RR in close analogy to the prevailing mechanism of the natural Mo-based nitrate reductase enzymes.     

The hydrolysis of the cerium(III) ion,Ce3+, in aqueous perchlorate solutions at 50°C

The hydrolysis equilibria of the Ce³⁺ ion have been studied at 50°C by measuring, with a glass electrode, the hydrogen ion concentration of Ce(ClO₄)₃ solutions. The Ce(III) concentration ranged from 0.1 to 1 m, while the ClO⁻₄ level was kept constant at 3 m by adding LiClO₄. Solutions containing hydrolysed species, in which at the most 0.4% of the Ce³⁺ can be transformed into reaction products without the formation of a precipitate, were prepared by constant-current coulometry. The potentiometric data have been explained in terms of Ce(OH)²⁺, Ce₂(OH)⁵⁺ and Ce₃(OH)⁴⁺₅ complexes. Their formation constants in the inert 3 m LiClO₄ medium are reported.     

Rapid microwave preparation of cerium-substituted sodium yttrium silicate phosphors for solid state white lighting

The preparation of two cerium-substituted sodium yttrium silicate phosphors, NaY₉Si₆O₂₆:Ce³⁺ and Na₃YSi₂O₇:Ce³⁺, was achieved using rapid heating via a modified microwave-assisted preparation technique. Activated carbon is used as a microwave susceptor allowing reaction temperatures greater than 1000 °C to be reached in minutes while producing the reducing atmosphere necessary to achieve Ce³⁺. Because this method immediately heats the sample and does not employ a H₂/N₂ gas mixture to maintain Ce³⁺ in its reduced state, volatilization of starting materials is limited, allowing the products to be prepared from a stoichiometric mixture of starting materials. The samples prepared were characterized using synchrotron X-ray powder diffraction and fluorescence spectroscopy. Photoluminescence measurements indicate NaY₉Si₆O₂₆:Ce³⁺ contains a broad excitation band in the UV ranging between 280 nm and 330 nm that produces a blue emission between 350 nm and 500 nm with a 10% quantum yield. Na₃YSi₂O₇:Ce³⁺ has a strong absorption band at 350 nm and also emits in the blue (375 nm–500 nm) with a quantum yield of 28%.     

Research on Molecular Structure and Electronic Properties of Ln3+ (Ce3+, Tb3+, Pr3+)/Li+ and Eu2+ Co-Doped Sr2Si5N8 via DFT Calculation

We use density functional theory (DFT) to study the molecular structure and electronic band structure of Sr₂Si₅N₈:Eu²⁺ doped with trivalent lanthanides (Ln³⁺ = Ce³⁺, Tb³⁺, Pr³⁺). Li⁺ was used as a charge compensator for the charge imbalance caused by the partial replacement of Sr²⁺ by Ln³⁺. The doping of Ln lanthanide atom causes the structure of Sr₂Si₅N₈ lattice to shrink due to the smaller atomic radius of Ln³⁺ and Li⁺ compared to Sr²⁺. The doped structure’s formation energy indicates that the formation energy of Li⁺, which is used to compensate for the charge imbalance, is the lowest when the Sr2 site is doped. Thus, a suitable Li⁺ doping site for double-doped lanthanide ions can be provided. In Sr₂Si₅N₈:Eu²⁺, the doped Ce³⁺ can occupy partly the site of Sr₁²⁺ ([SrN₈]), while Eu²⁺ accounts for Sr₁²⁺ and Sr₂²⁺ ([SrN₁₀]). When the Pr³⁺ ion is selected as the dopant in Sr₂Si₅N₈:Eu²⁺, Pr³⁺ and Eu²⁺ would replace Sr₂²⁺ simultaneously. In this theoretical model, the replacement of Sr²⁺ by Tb³⁺ cannot exist reasonably. For the electronic structure, the energy level of Sr₂Si₅N₈:Eu²⁺/Li⁺ doped with Ce³⁺ and Pr³⁺ appears at the bottom of the conduction band or in the forbidden band, which reduces the energy bandgap of Sr₂Si₅N₈. We use DFT+U to adjust the lanthanide ion 4f energy level. The adjusted 4f-CBM of Ce_Sr1Li_Sr1-Sr₂Si₅N₈ is from 2.42 to 2.85 eV. The energy range of 4f-CBM in Pr_Sr1Li_Sr1-Sr₂Si₅N₈ is 2.75–2.99 eV and its peak is 2.90 eV; the addition of Ce³⁺ in Eu_Sr1Ce_Sr1Li_Sr1 made the 4f energy level of Eu²⁺ blue shift. The addition of Pr³⁺ in Eu_Sr2Pr_Sr2Li_Sr1 makes part of the Eu²⁺ 4f energy level blue shift. Eu²⁺ 4f energy level in Eu_Sr2Ce_Sr1Li_Sr1 is not in the forbidden band, so Eu²⁺ is not used as the emission center.     

Scintillation of Sol-Gel Derived Lutetium Orthophosphate Doped with Rare Earth Ions

In this paper, the synthesis, the characterization and the scintillation properties of LuPO₄ doped, with several concentrations of Ce³⁺, Eu³⁺ and Tb³⁺ ions, are presented. These materials have been synthesized by sol-gel process. The purity of powders has been verified by X-Ray diffraction and the results confirm the xenotime structure of all the materials. A thermogravimetric analysis allows the obtention of informations on the crystallisation of LuPO₄ and the study of its evolution from the amorphous to crystalline form. The morphology of the powders has been studied by Scanning Electron Microscopy and shows that the powders are constituted of small particles with narrow size distribution. Optical properties have been studied in order to determine the scintillation performances of these materials. The optima are obtained for Ce³⁺, Eu³⁺ and Tb³⁺ concentration of respectively 0.1, 10 and 5% with high scintillation yields. This study thus confirms the potentialities of these materials as scintillators.     

Synthesis of highly fluorescent LaF3:Ln/LaF3 core/shell nanocrystals by a surfactant-free aqueous solution route

A surfactant-free aqueous solution route has been established for the synthesis of LaF₃:Ln³⁺/LaF₃ core/shell nanocrystals (Ln=Ce, Tb, Nd) heated at 75 °C at ambient pressure. All the as-prepared nanocrystals with spherical shape have an average size around 20 nm, and consist of well crystallized hexagonal phases. The X-ray photoelectron spectra was used to confirm that the LaF₃ shells have coated the LaF₃:Ce³⁺, Tb³⁺ cores. Compared with that of the original cores under the same conditions, the emission intensity of the LaF₃:Ce³⁺, Tb³⁺/LaF₃ and LaF₃:Nd³⁺/LaF₃ core/shell nanocrystals increased significantly of 120% and 60%, respectively. The quantum yield of the LaF₃:Ce³⁺, Tb³⁺/LaF₃ core/shell nanocrystals reached about 27% in aqueous solution. These results indicate that a significant reduction of the quenching from the surface of the core nanocrystals can be obtained by the synthesis of the core/shell structures, and this method can provide more desirable lanthanide-doped nanocrystals for potential biological applications.     

DNA Intercalating Near-Infrared Luminescent Lanthanide Complexes Containing Dipyrido[3,2-a:2′,3′-c]phenazine (dppz) Ligands: Synthesis,Crystal Structures,Stability, Luminescence Properties and CT-DNA Interaction

In order to create near-infrared (NIR) luminescent lanthanide complexes suitable for DNA-interaction, novel lanthanide dppz complexes with general formula [Ln(NO₃)₃(dppz)₂] (Ln = Nd³⁺, Er³⁺ and Yb³⁺; dppz = dipyrido[3,2-a:2′,3′-c]phenazine) were synthesized, characterized and their luminescence properties were investigated. In addition, analogous compounds with other lanthanide ions (Ln = Ce³⁺, Pr³⁺, Sm³⁺, Eu³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Tm³⁺, Lu³⁺) were prepared. All complexes were characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray diffraction analysis of the complexes (Ln = La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Eu³⁺, Er³⁺, Yb³⁺, Lu³⁺) showed that the lanthanide’s first coordination sphere can be described as a bicapped dodecahedron, made up of two bidentate dppz ligands and three bidentate-coordinating nitrate anions. Efficient energy transfer was observed from the dppz ligand to the lanthanide ion (Nd³⁺, Er³⁺ and Yb³⁺), while relatively high luminescence lifetimes were detected for these complexes. In their excitation spectra, the maximum of the strong broad band is located at around 385 nm and this wavelength was further used for excitation of the chosen complexes. In their emission spectra, the following characteristic NIR emission peaks were observed: for a) Nd³⁺: ⁴F_3/2 → ⁴I_9/2 (870.8 nm), ⁴F_3/2 → ⁴I_11/2 (1052.7 nm) and ⁴F_3/2 → ⁴I_13/2 (1334.5 nm); b) Er³⁺: ⁴I_13/2 → ⁴I_15/2 (1529.0 nm) c) Yb³⁺: ²F_5/2 → ²F_7/2 (977.6 nm). While its low triplet energy level is ideally suited for efficient sensitization of Nd³⁺ and Er³⁺, the dppz ligand is considered not favorable as a sensitizer for most of the visible emitting lanthanide ions, due to its low-lying triplet level, which is too low for the accepting levels of most visible emitting lanthanides. Furthermore, the DNA intercalation ability of the [Nd(NO₃)₃(dppz)₂] complex with calf thymus DNA (CT-DNA) was confirmed using fluorescence spectroscopy.     

Coordination and recognition of lanthanide cations by a methyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril

The interactions between a series of lanthanide cations (Ln³⁺) and a methyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril (SHMeQ[6]) in the presence of [CdCl₄]^2 ? as a structure-directing agent in aqueous HCl solutions (6.0 mol·L ^? 1) have been investigated. The formation of ionic radius-dependent complexes, the crystal structures of six of which have been obtained, shows the recognition ability of SHMeQ[6] towards lanthanide cations. For example, SHMeQ[6] forms molecular capsule-like complexes with the two lightest lanthanide cations, La³⁺ and Ce³⁺; molecular pairs with Nd³⁺, Sm³⁺, Eu³⁺ and Gd³⁺, and no solid crystals are formed with the heavier lanthanides.     

Synthesis and photoluminescence properties of tunable emission phosphors Ca4Si2O7F2:Ce3+

The Ce³⁺ activated phosphors Ca₄Si₂O₇F₂:Ce³⁺ are prepared by a solid state reaction technique. The UV–vis luminescence properties as well as fluorescence decay time spectra are investigated and discussed. The results revealed that there were two kinds of Ce³⁺ luminescence behavior with 408 and 470 nm emissions, respectively. Under 355 nm excitation, the Ce(1) emission (408 nm) is dominant at low doping concentration, and then the Ce(2) emission (470 nm) get more important with increasing of Ce³⁺ concentrations in the host. The phosphors Ca₄Si₂O₇F₂:xCe³⁺ show tunable emissions from blue area to green-blue area under near-ultraviolet light excitation, indicating a potential application in near-UV based w-LEDs.     

Rare-earth-doped glasses for fiber amplifiers in broadband telecommunication

Rare-earth-doped optical amplifiers have a great potential for broadband Wavelength-Division-Multiplexed (WDM) telecommunication by tailoring host glass compositions. In order to design the emission spectra of doped rare-earth ions, it is important to understand the relationship between the local ligand field and various optical properties of specific 4f-levels, such as the radiative transition probability, the nonradiative decay probability, which dominate the spectral line width and quantum efficiency of amplification transitions. For the Er³⁺:1.55 μm transition, the role of the Judd–Ofelt Ω₆ parameters is presented, which is correlated to the Er–ligand bond covalency in glasses. The Tm³⁺: 1.46-μm transition shows quantum efficiency over 90% high enough for the S-band application, in heavy metal oxide glasses with moderate phonon energy and wider spectra than fluorides. A way to improve population inversion by selective energy transfer with codoped lanthanide ions is presented. Finally, the energy level structures and resultant spectral properties of Pr³⁺, Nd³⁺ and Dy³⁺ ions, 1.3-μm-active ions, are compared. The hypersensitivity of Dy³⁺ transitions appears especially in chalcogenide glasses, where the nonradiative loss due to multiphonon decay is also minimized. In conclusion, glass materials have opportunities to vary the radiative cross section, quantum efficiency, and gain flatness, which are important for novel amplifiers in the future DWDM system.