Enhancement of Upconversion Luminescence through Three-Dimensional Design of Plasma Ti3O5-Coupled Structural Domain-Limiting Effects.

Upconversion luminescence plays a crucial role in various technological applications, and among the various valence states of lanthanide elements, Ln3+ has the highest stability. The 4f orbitals of these elements are in a fully empty, semifull, or full state. This special 4f electron configuration allows them to exhibit rich discrete energy levels. However, the 4f-4f transition of Ln3+ rare earth ions itself is prohibited, resulting in a lower luminescence efficiency. This limitation greatly hinders the practical application of upconversion luminescence. In this study, we report nanostructured luminescence-enhanced substrate platforms with both semiconductive local surface plasmons and spatially confined domain effects on a single defect semiconductor substrate. By coupling NaYF4:Yb-Er nanoparticle emitters to the surface of Ti3O5 NC-arrays plasmonic nanostructures, an ultrabright luminescence with a 32-fold increase in green emission and a 40-fold increase in red emission was achieved. Furthermore, the fluorescence resonance energy transfer characteristics observed in the R6G/NaYF4/Ti3O5 NC-array composite film enable accurate detection of fluorescent molecules. The results provide an innovative and intelligent approach to enhance the upconversion luminescence intensity of rare-doped nanoparticles and develop highly sensitive molecular detection systems based on the above luminescence enhancement.

Strategy of Charge Compensation for High-Performance Ni2+-Activated MgAl2O4 Spinel Near-Infrared Phosphor Synthesis via the Sol-Gel Combustion Method.

Near-infrared (NIR) phosphor conversion light-emitting diodes (pc-LEDs) have great application potential as NIR light sources in many fields such as food analysis, night vision illumination, and bioimaging for noninvasive medical diagnosis. In general, phosphors synthesized by a high-temperature solid-phase method have large particle sizes and have to be processed to fine powders by a grinding process, which may introduce surface defects and lower the luminous efficiency. Here, we report a sol-gel sintering method with ammonium nitrate and citric acid as the sacrificing agents to synthesize high purity, nanosized (less than 50 nm) Zr4+/Ni2+ codoped MgAl2O4 spinel NIR phosphors, in which MgAl2O4 spinel is the matrix, Ni2+ is the luminous center, and Zr4+ acts as the charge compensator. We systematically characterized the crystal structures and NIR luminescence properties of the Ni2+-doped MgAl2O4 and the Zr4+/Ni2+ codoped MgAl2O4. Under 390 nm light excitation, the emission spectrum of the Ni2+-doped MgAl2O4 phosphor covers 900-1600 nm, the half-peak width is 251 nm, and the peak position is located at 1230 nm. We demonstrated that by incorporating small amounts of Zr4+ as the charge compensator, the NIR emission intensity of the Zr4+/Ni2+ codoped MgAl2O4 nanosized phosphor was doubled over that of the Ni2+-doped MgAl2O4 phosphor. The optimal content of the charge compensator was 2 mol %. More importantly, the inclusion of Zr4+ led to a NIR phosphor with improved thermal stability in luminous properties, and the luminous intensity measured at 100 °C was 33.83% of that measured at room temperature (20 °C). This study demonstrates that NIR phosphor nanomaterials with high-purity and enhanced optical properties can be designed and synthesized through the charge compensation strategy by a sol-gel sintering method.

Enhanced Storage Capacity via Anion Substitution for Advanced Delayed X-ray Detection.

X-ray radiation information storage, characterized by its ability to detect radiation with delayed readings, shows great promise in enabling reliable and readily accessible X-ray imaging and dosimetry in situations where conventional detectors may not be feasible. However, the lack of specific strategies to enhance the memory capability dramatically hampers its further development. Here, we present an effective anion substitution strategy to enhance the storage capability of NaLuF4:Tb3+ nanocrystals attributed to the increased concentration of trapping centers under X-ray irradiation. The stored radiation information can be read out as optical brightness via thermal, 980 nm laser, or mechanical stimulation, avoiding real-time measurement under ionizing radiation. Moreover, the radiation information can be maintained for more than 13 days, and the imaging resolution reaches 14.3 lp mm-1. These results demonstrate that anion substitution methods can effectively achieve high storage capability and broaden the application scope of X-ray information storage.

Upconversion 3D Bioprinting for Noninvasive In Vivo Molding.

Tissue engineered bracket materials provide essential support for the physiological protection and therapeutics of patients. Unfortunately, the implantation process of such devices poses the risk of surgical complications and infection. In this study, an upconversion nanoparticles (UCNPs)-assisted 3D bioprinting approach is developed to realize in vivo molding that is free from invasive surgery. Reasonably designed UCNPs, which convert near-infrared (NIR) photons that penetrate skin tissues into blue-violet emission (300-500 nm), induce a monomer polymerization curing procedure in vivo. Using a fused deposition modeling coordination framework, a precisely predetermined trajectory of the NIR laser enables the manufacture of implantable medical devices with tailored shapes. A proof of the 3D bioprinting of a noninvasive fracture fixation scaffold is achieved successfully, thus demonstrating an entirely new method of in vivo molding for biomedical treatment.

A review of metal-organic framework (MOF) materials as an effective photocatalyst for degradation of organic pollutants.

Water plays a vital role in all aspects of life. Recently, water pollution has increased exponentially due to various organic and inorganic pollutants. Organic pollutants are hard to degrade; therefore, cost-effective and sustainable approaches are needed to degrade these pollutants. Organic dyes are the major source of organic pollutants from coloring industries. The photoactive metal-organic frameworks (MOFs) offer an ultimate strategy for constructing photocatalysts to degrade pollutants present in wastewater. Therefore, tuning the metal ions/clusters and organic ligands for the better photocatalytic activity of MOFs is a tremendous approach for wastewater treatment. This review comprehensively reports various MOFs and their composites, especially POM-based MOF composites, for the enhanced photocatalytic degradation of organic pollutants in the aqueous phase. A brief discussion on various theoretical aspects such as density functional theory (DFT) and machine learning (ML) related to MOF and MOF composite-based photocatalysts has been presented. Thus, this article may eventually pave the way for applying different structural features to modulate novel porous materials for enhanced photodegradation properties toward organic pollutants.

Achieving Multicolor Emitting of Antimony-Doped Indium-Based Halide Perovskite via Monovalent Metal Induced Phase Engineering.

Lead-free metal halide perovskites have attracted attention because of their excellent optical properties and nontoxicity. Here, we report the synthesis of Sb3+-doped indium halide perovskite Cs2InCl5·H2O:Sb3+ by an improved solution coprecipitation method. The treatment of the Sb3+-doped indium halide perovskite with selected monovalent cation halides led to Cs2MInCl6 (Ag+, K+, Na+) in different crystal structures or phases. Sb3+ has an isolated ns2 electron, and Sb3+-doped metal halide acts as the luminescence center and exhibits bright broadband emission that originated from self-trapped excitons. Under UV light excitation, these phosphors with different crystal structures emitted multicolored luminescence ranging from blue, green, yellow, and red depending on whether or not or which monovalent metal ion was used. The phosphor samples were used to print high-resolution 2D color barcodes for security and anticounterfeiting applications. The study presented here provides a new approach for the design and synthesis of lead-free metal halide perovskites with different crystal structures and unique optical properties.

The effect of MnCO3 on the gain coefficient for the 4I13/2 → 4I15/2 transition of Er3+ ions and near-infrared emission bandwidth flatness of Er3+/Tm3+/Yb3+ co-doped barium zinc silicate glasses.

The roles of Mn2+ ions in the MnCO3 compound, leading to the formation of an Mn2+-Yb3+ dimer and affecting the gain coefficient for the 4I13/2 → 4I15/2 transition of Er3+ ions and near-infrared (NIR) emission bandwidth flatness of Er3+/Tm3+/Yb3+ co-doped in SiO2-ZnO-BaO (SZB) barium zinc silicate glasses, were investigated in this work. The composition of all elements from the original raw materials that exist in the host glasses was determined using energy-dispersive X-ray spectroscopy (EDS). Under the excitation of a 980 nm laser diode (LD), the NIR emission of Er3+/Tm3+/Yb3+-co-doped SZB glasses produced a bandwidth of about 430 nm covering the O, E, and C bands. The effects of Mn2+ ions and the Mn2+-Yb3+ dimer on the gain coefficient for the 4I13/2 → 4I15/2 transition of Er3+ ions and bandwidth flatness of NIR emission of Er3+/Tm3+-co-doped and Er3+/Tm3+/Yb3+-co-doped SZB glasses were also assigned. The optimal molar concentration of Mn2+ ions was determined such that the NIR bandwidth flatness of Er3+/Tm3+/Yb3+-co-doped SZB glasses was the flattest. In addition, the role of Mn2+ ions in reducing the gain coefficient for the 4I13/2 → 4I15/2 transition of Er3+ ions was also calculated and discussed.

An Er3+-Doped Cs2NaScCl6 Lead-Free Double Perovskite with Efficient Broadband Visible to Near-Infrared Emission and Multimodal Upconversion Luminescence.

Lanthanide ions are widely used as dopants for halide perovskites for their broad energy level coverage from the visible to near-infrared (NIR) range. In this work, Cs2NaScCl6:Er3+ was synthesized by an improved solid-state reaction method, which showed effective NIR emission under ultraviolet excitation. Through calculations based on density functional theory and Bader charge analysis, it is shown that [ErCl6]3- octahedra show a strong localization effect in the Cs2NaScCl6:Er3+ lattice, which is conducive to the charge transfer process of Cl-Er3+, and charge transfer sensitization is responsible for the efficient visible to NIR luminescence of Er3+, where the NIR emission around λem = 1540 nm originated from the Er3+:4I13/2 → 4I15/2 transition with an ultrahigh photoluminescence quantum yield that reached ∼28.3%. Notably, Cs2NaScCl6:Er3+ also exhibited bright upconversion luminescence of green light (at 540 nm) under excitation by a variety of NIR laser diodes (808, 980, and 1550 nm) via self-sensitization processes.

Synthesis and Photoluminescence Modulation of Cs4Cd1-xMnxBi2Cl12-Based Two-Dimensional Layered Double Perovskites.

Two-dimensional (2D) layered double perovskites have attracted much attention because of their excellent photoelectric properties. However, few reports have been published on the synthesis of 2D layered double perovskites from halide perovskites as precursors. Here, we report that CsCdCl3 and Cs3Bi2Cl9 were synthesized by the coprecipitation method, and a two-dimensional layered double perovskite Cs4CdBi2Cl12 was readily synthesized by mixing the two halide perovskites. We doped different amounts of Mn2+ into CsCdCl3 to form CsCd1-xMnxCl3, which introduced impurity states into the energy level and exhibited an orange-red light emission that is characteristic of Mn2+. A series of 2D layered double perovskites Cs4Cd1-xMnxBi2Cl12 were synthesized from CsCd1-xMnxCl3 and Cs3Bi2Cl9, which showed a bright orange-yellow luminescence under ultraviolet excitation. The presence of high concentrations of Cd2+ in the two-dimensional layered double perovskites weakened the strong Mn-Mn coupling and suppressed the energy transfer to defects, thus minimizing nonradiative decay and promoting efficient energy transfer. Our work provides a new concept for the synthesis of low-dimensional metal halide perovskites with unique optical properties.

Visualized X-ray Dosimetry for Multienvironment Applications.

X-ray dose detection plays a critical role in various scientific fields, including chemistry, materials, and medicine. However, the current materials used for this purpose face challenges in both immediate and delayed radiation detections. Here, we present a visual X-ray dosimetry method for multienvironment applications, utilizing NaLuF4 nanocrystals (NCs) that undergo a color change from green to red upon X-ray irradiation. By adjustment of the concentrations of Ho3+, the emission color of the NCs can be tuned thanks to the cross-relaxation effects. Furthermore, X-ray irradiation induces generation of trapping centers in NaLuF4:Ho3+ NCs, endowing the generation of mechanoluminescence (ML) behavior upon mechanical stimulation after X-ray irradiation ceases. The ML intensity shows a linear correlation with the X-ray dose, facilitating the detection of delayed radiation. This breakthrough facilitates X-ray dose inspection in flaw detection, nuclear medicine, customs, and civil protection, thereby enhancing opportunities for radiation monitoring and control.

A mini review on metal-organic framework-based electrode materials for capacitive deionization.

Capacitive deionization (CDI) is an electrochemical method of extracting ions from solution at potentials below electrolysis. It has various applications ranging from water remediation and desalination to heavy metal removal and selective resource recovery. A CDI device applies an electrical charge across two porous electrodes to attract and remove ions without producing waste products. It is generally considered environmentally friendly and promising for sustainability, yet ion removal efficiency still falls short of more established filtration methods. Commercially available activated carbon is typically used for CDI, and its ion adsorption capacity is low at approximately 20-30 mg g-1. Recently, much interest has been in the highly porous and well-structured family of materials known as metal-organic frameworks (MOFs). Most MOFs are poor conductors of electricity and cannot be directly used to make electrodes. A common workaround is to pyrolyze the MOF to convert its organic components to carbon while maintaining its underlying microstructure. However, most MOF-derived materials only retain partial microstructure after pyrolysis and cannot inherit the robust porosity of the parent MOFs. This review provides a systematic breakdown of structure-performance relationships between a MOF-derived material and its CDI performance based on recent works. This review also serves as a starting point for researchers interested in developing MOF-derived materials for CDI applications.

Achieving Broadband NIR-I to NIR-II Emission in an All-Inorganic Halide Double-Perovskite Cs2NaYCl6:Cr3+ Phosphor for Night Vision Imaging.

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) offer numerous advantages, including compact size, tunable emission spectra, energy efficiency, and high integration potential. These features make them highly promising for various applications, such as night vision monitoring, food safety inspection, biomedical imaging, and theragnostics. All-inorganic halide double-perovskite materials, known for their large absorption cross section, excellent defect tolerance, and long carrier diffusion radius, serve as unique matrices for constructing near-infrared fluorescent materials. In this study, we successfully prepared the all-inorganic metal halide double-perovskite Cs2NaYCl6:Cr3+ using a grinding-sintering method. A small fraction of the [YCl6] octahedra within the host material's lattice was substituted with Cr3+ ions, resulting in the creation of the Cs2NaYCl6:Cr3+ phosphor. When excited with λ = 310 nm UV light, the phosphor exhibited a broad emission range spanning from 800 to 1400 nm, covering the NIR-I and NIR-II regions. It had a broad bandwidth emission of 185 nm and achieved a fluorescence quantum yield of 20.2%. The unique broadband emission of the phosphor originates from the weak crystal field environment provided by the Cs2NaYCl6 host matrix, which enhances the luminescence properties of the Cr3+ ions. To create NIR pc-LEDs, the phosphor was encapsulated onto a commercially available UV LED chip operating at 310 nm. The potential application of these NIR pc-LEDs in night vision imaging was successfully validated.

Long-Wavelength Near-Infrared Divalent Nickel-Activated Double-Perovskite Ba2MgWO6 Phosphor as Imaging for Human Fingers.

Transmission near-infrared (NIR) imaging technology has great potential for biomedical imaging because of its lower water absorption coefficient and highly reduced photon scattering effect in biological tissues compared to visible light. The extent of biological tissue photon scattering is inversely proportional to wavelength; therefore, in principle, imaging with long-wavelength NIR helps improve the resolution of the optical image, but deep tissue high-resolution luminescence imaging is still very challenging technically. Here, we report the discovery of a Ba2MgWO6:Ni2+ double perovskite phosphor that emits broadband long-wavelength NIR (1200-2000 nm) under 365 nm near-ultraviolet (UV) excitation, with a full width at half-maximum of 255 nm. The luminescence quantum efficiency of the phosphor with optimized composition reached 16.67%. The analysis of the crystal structure of Ba2MgWO6:Ni2+ suggests that Ni2+ ions preferentially occupy the W6+ site in octahedrons with a weak crystal field, which leads to a large Stokes shift. An as-prepared long-wavelength NIR pc-LED device was built by packaging an optimized phosphor with a low-power near-UV-LED chip, which was tested to generate clear imaging of venous vessels in human fingers. These unique properties of the Ba2MgWO6:Ni2+ double perovskite phosphor makes it a promising application in the field of imaging sources for body tissue..

Tailor Traps in Bi3+-Doped NaGdGeO4 Phosphors by Introducing Eu3+ Ions to Switch Multimodal Phosphorescence Emission.

Featured with a tunable excitation/emission wavelength and excellent physicochemical stability, inorganic fluorescent materials are widely used in the fields of anti-counterfeiting. Here, we design a multi-stimuli-responsive dynamic fluorescence and phosphorescence anti-counterfeiting material by introducing Eu3+ ions in NaGdGeO4: Bi3+ to tailor the trap structure. The photoluminescence (PL), long persistent luminescence (LPL), and photo-stimulated luminescence (PSL) colors of NaGdGeO4: Bi3+, Eu3+ can be switched by varying the excitation modes (ultraviolet, near infrared, and X-ray light). Especially, the LPL and PSL colors of NaGdGeO4: Bi3+, Eu3+ vary with increasing decay and stimulation times. In addition, X-ray excitation ensures the specificity of the luminescence of NaGdGeO4: Bi3+, Eu3+ compared with ultraviolet excitation. This rapidly-changing-color fluorescent material offers the possibility of sophisticated anti-counterfeiting applications in the future.

Core-Shell Tandem Catalysis Coupled with Interface Engineering For High-Performance Room-Temperature Na-S Batteries.

The sluggish redox kinetics and shuttle effect seriously impede the large application of room-temperature sodium-sulfur (RT Na-S) batteries. Designing effective catalysts into cathode material is a promising approach to overcome the above issues. However, considering the multistep and multiphase transformations of sulfur redox process, it is impractical to achieve the effective catalysis of the entire S8 →Na2 Sx →Na2 S conversion through applying a single catalyst. Herein, this work fabricates a nitrogen-doped core-shell carbon nanosphere integrated with two different catalysts (ZnS-NC@Ni-N4 ), where isolated Ni-N4 sites and ZnS nanocrystals are distributed in the shell and core, respectively. ZnS nanocrystals ensure the rapid reduction of S8 into Na2 Sx (4 < x ≤ 8), while Ni-N4 sites realize the efficient conversion of Na2 Sx into Na2 S, bridged by the diffusion of Na2 Sx from the core to shell. Besides, Ni-N4 sites on the shell can also induce an inorganic-rich cathode-electrolyte interface (CEI) on ZnS-NC@Ni-N4 to further inhibit the shuttle effect. As a result, ZnS-NC@Ni-N4 /S cathode exhibits an excellent rate-performance (650 mAh g-1 at 5 A g-1 ) and ultralong cycling stability for 2000 cycles with a low capacity-decay rate of 0.011% per cycle. This work will guide the rational design of multicatalysts for high-performance RT Na-S batteries.

High Thermal Stability of Copper-Based Perovskite Scintillators for High-Temperature X-ray Detection.

High-temperature scintillation detectors play a significant role in oil exploration. However, traditional scintillators have limited ability to meet the requirements of practical applications owing to their low thermal stability. In this study, we designed and developed a one-dimensional (1D) Cs5Cu3Cl6I2 scintillator with high thermal stability. In addition, by preparing Cs5Cu3Cl7I, we proved that the Cs5Cu3Cl6I2 scintillator exhibits high thermal stability because the bridges linking the structural units in the 1D chain structure are only formed by I- ions, which improve their structural rigidity. The scintillator has a high steady-state light yield (59,700 photons MeV-1) and exhibits the highest spatial resolution for powder-based scintillation screens (18 lp mm-1) after cyclic treatment within the temperature range of 298-423 K. The Cs5Cu3Cl6I2 scintillator allows the visualization of alloy melting, indicating that it has significant potential for application in high-temperature environments. This study provides a new perspective toward the design of scintillators with high thermal stability.

Mechano-luminescence Behavior of Lanthanide-Doped Fluoride Nanocrystals for Three-Dimensional Stress Imaging.

Pervasive mechanical force in nature and human activities is closely related to intriguing physics and widespread applications. However, describing stress distribution timely and precisely in three dimensions to avoid "groping in the dark" is still a formidable challenge, especially for nonplanar structures. Herein, we realize three-dimensional (3D) stress imaging for sharp arbitrary targets via advanced 3D printing, owing to the use of fluoride nanocrystal(NC)-based ink. Notably, a fascinating mechano-luminescence (ML) is observed for the homogeneously dispersed NaLuF4:Tb3+ NCs (∼25 nm) with rationally designed deep traps (at 0.88 and 1.02 eV) via incorporating Cs+ ions and using X-ray irradiation. Carriers captured in the corresponding traps are steadily released under mechanical stimulations, which enables a ratio metric luminescence intensity based on the applied force. As a result, a significant mechano-optical conversion and superior optical waveguide of the corresponding transparent printed targets demonstrate stress in 3D with a high spatial and temporal resolution based on stereovision. These results highlight the optical function of the 3D-printed fluoride NCs, which cast light into the black boxes of stress described in space, benefiting us in understanding the ubiquitous force relevant to most natural and engineering processes.

Engineering CsPbX3 (X = Cl, Br, I) Quantum Dot-Embedded Borosilicate Glass through Self-Crystallization Facilitated by NaF as a Phosphor for Full-Color Illumination and Laser-Driven Projection Displays.

All inorganic perovskite (CsPbX3, X = Cl, Br, I) quantum dot (QD) glass samples are considered the next generation of lighting materials for their excellent luminescence properties and stability, but crystallization conditions are difficult to control, which often leads to the inhomogeneous crystallinity of QDs. Here, we provided evidence that the presence of sodium fluoride induced self-crystallization of CsPbBr3 QDs during routine glass formation without the need for additional heat treatment. We showed that NaF simultaneously affected the network structure of glass and promoted the formation of CsPbBr3 QDs, that is, Na+ ions entered the glass network skeleton, partially interrupting the network structure, while the strong electronegativity of F- ions attracted Cs+ and Pb2+ ions into the gaps formed in the glass networks that had been loosened up by Na+ ions, which reduced the activation energy of crystallization processes. Our results showed that NaF-induced CsPbBr3 QDs glass had excellent thermal stability, high photoluminescence quantum efficiency (49%), and luminescent stability under high-power laser irradiation. Finally, this work also demonstrated the general applicability of this method in the making of a series of CsPbX3 (X = Cl, Br, I) QD glass samples by NaF-induced self-crystallization, which drastically expanded the color gamut to a range of full spectrum for luminescence and laser-driven projection displays. We believe that the work presented here represents a new direction for the research and development of full-color gamut inorganic perovskite quantum dot glass samples, which could have a significant impact on the future applications of laser-driven projection displays as well.

Multi-Dimensional Mechanical Mapping Sensor Based on Flexoelectric-Like and Optical Signals.

Mechanical sensors execute multi-mode response to external force, which are cornerstones for applications in human-machine interactions and smart wearable equipments. Nevertheless, an integrated sensor responding to mechanical stimulation variables and providing the information of the corresponding signals, as velocity, direction, and stress distribution, remains a challenge. Herein, a Nafion@Ag@ZnS/polydimethylsiloxanes (PDMS) composite sensor is explored, which realizes the description of mechanical action via optics and electronics signals simultaneously. Combined with the mechano-luminescence (ML) originated from ZnS/PDMS and the flexoelectric-like effect of Nafion@Ag, the corresponding explored sensor achieves the detection of magnitude, direction, velocity, mode of mechanical stimulation, and the visualization of the stress distribution. Moreover, the outstanding cyclic stability, linearity response character, and rapid response time are demonstrated. Accordingly, the intelligent recognition and manipulation of a target are realized, which indicate a smarter human-machine interface sensing applied for wearable devices and mechanical arms can be expected.

Optical band gaps and spectroscopy properties of Bi m+/Eu n+/Yb3+ co-doped (m = 0, 2, 3; and n = 2, 3) zinc calcium silicate glasses.

In this study, the indirect/direct optical band gaps and spectroscopy properties of Bi m+/Eu n+/Yb3+ co-doped (m = 0, 2, 3; and n = 2, 3) zinc calcium silicate glasses under different excitation wavelengths were investigated. Zinc calcium silicate glasses with the main compositions of SiO2-ZnO-CaF2-LaF3-TiO2 were prepared by the conventional melting method. EDS analysis was performed to determine the elemental composition existing in the zinc calcium silicate glasses. Visible (VIS)-, upconversion (UC)-, and near-infrared (NIR)-emission spectra of Bi m+/Eu n+/Yb3+ co-doped glasses were also investigated. Indirect optical band gaps and direct optical band gaps of Bi m+-, Eu n+- single-doped, and Bi m+-Eu n+ co-doped SiO2-ZnO-CaF2-LaF3-TiO2-Bi2O3-EuF3-YbF3 zinc calcium silicate glasses were calculated and analyzed. CIE 1931(x, y) color coordinates for VIS and UC emission spectra of Bi m+/Eu n+/Yb3+ co-doped glasses were determined. Besides, the mechanism of VIS-, UC-, NIR-emissions, and energy transfer (ET) processes between Bi m+ and Eu n+ ions were also proposed and discussed.