Near-infrared Luminescent Materials Research Articles

Luminescence and Transport Behavior in Incommensurately Modulated CaGd2(MoO4)4:Yb/Er.

The phenomenon of thermal quenching of luminescence can significantly compromise the efficiency of luminescent materials, a process accompanied by the generation of substantial phonon populations. While plenty of models for elucidating this behavior have been proposed, the crucial role of phonon transport has largely been neglected, particularly in the enigmatic incommensurate scheelite structure with good luminescence performance. In this study, we delve into the thermal quenching dynamics of the near-infrared emission in the incommensurately modulated CaGd2(MoO4)4:Yb/Er system. Our comprehensive investigation reveals distinct evolutionary patterns in electrical conductivity, luminescence intensity, thermal conductivity, and Raman scattering at varying temperature regimes. Notably, we have determined that thermally induced ion migration, occurring above ∼300 °C, serves as a pivotal trigger for the activation of all phonons and the enhancement of phonon-defect scattering within this incommensurate framework. This phenomenon not only diminishes the thermal conductivity but also accelerates the multiphonon relaxation of the Er3+ emission levels, culminating in a marked thermal quenching of luminescence. This work illuminates the thermal quenching mechanism of luminescence by focusing on phonon scattering dynamics, providing critical insights for the design of thermally robust near-infrared luminescent materials, which are essential for the advancement of optical amplification systems.

Introducing electron-rich thiophene bridges in hot exciton emitter for efficient non-Doped near-infrared OLEDs with low turn-on voltages

The development of near-infrared (NIR) luminescent materials featuring high photoluminescence quantum yield (ΦPL) at aggregated state is of great significance for achieving highly efficient non-doped organic light-emitting diodes (OLEDs) but remains formidable challenging. Herein, a design strategy of introducing electron-rich thiophene groups between electron acceptor and donor is proposed for efficient NIR luminescent materials, and a tailored D-π-A-π-D type emitter, namely, 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diylbis(thiophene-5,2-diyl))bis(N,N-diphenylaniline) (TPATBT), is designed and prepared. The photophysical investigation and density functional theory analysis disclose that TPATBT is a hot exciton emitter feature with hybridized local and charge-transfer state. Additionally, TPATBT demonstrates aggregation-induced emission characteristic, prefers high thermal stability, and exhibits a strong emission at 692 nm with a decent ΦPL of 20 % in the neat film. The non-doped device based on TPATBT neat film presents a maximum external quantum efficiency (ηext,max) of 1.22 % with electroluminescence peak at 718n m. Moreover, we first try to use interlayer sensitization to sensitize non-doped devices, which achieves better ηext,max of 1.34 % with low turn-on voltage of 3.2 V. The proposed molecular design strategy in this work is promising for exploring robust NIR luminescent materials for high-performance OLEDs.

The Molecular Design and Electroluminescent Performance of Near-Infrared (NIR) Iridium(III) Complexes Bearing Isoquinoline-, Phthalazine- and Phenazine-Based Ligands.

Near-infrared (NIR) light has characteristics of invisibility to human eyes, less background interference, low light scattering, and strong cell penetration. Therefore, NIR luminescent materials have significant applications in imaging, sensing, energy, information storage and display. The development of NIR luminescent materials thus has emerged as a highly dynamic area of research in the realm of contemporary materials. To date, NIR luminescent materials are roughly divided into inorganic materials and organic materials. Compared with inorganic materials, organic NIR luminescent materials have become a hot research topic in recent years due to their rich sources, easy control of structure, simple preparation process, low cost, and good film-forming properties. Among them, iridium(III) [Ir(III)] complexes exhibit excellent properties such as thermal stability, simple synthesis, easy color modulation, short excited state lifetimes, and high brightness, thus becoming one of the ideal luminescent material systems for preparing high-quality organic light-emitting diodes. Therefore, how to obtain Ir(III) complexes with NIR emission and high efficiency through molecular design is a necessary and promising research topic. This work reviews the research progress of representative NIR Ir(III) complexes bearing isoquinoline-, phenazine-, and phthalazine-based ligands reported in recent years and introduces the design strategies and electroluminescent performances of NIR Ir(III) complexes.

High-Stability Near-Infrared Luminescent Glass Ceramic and Its Applications.

Near-infrared (NIR) light, valuable for its biological penetration and invisibility to the human eye, is a crucial tool in biomedicine, environmental monitoring, anticounterfeiting, and information encryption, yet traditional NIR luminescent materials are often unstable in humid conditions. Here, a highly stable MgGeO3:Mn2+ glass ceramic (GC) with NIR luminescence was successfully synthesized. As-obtained GC700 boasts exceptional luminescent capabilities and possesses abundant trap structures, enabling data inscription with a 405 nm laser and retrieval via laser/thermal excitation. Moreover, the emission peak of Mn2+ can be manipulated from 630 to 691 nm by increasing the annealing treatment temperature. With the harnessing of the effective NIR emission, stable carrier characteristics, and numerous trap structures, there is potential for application in information encryption. Accordingly, we explored the application of MgGeO3:Mn2+ GC (GC700 and GC800) samples in precious three-dimensional (3D) information storage and NIR mechanoluminescence (ML) for biological tissue imaging. These applications demonstrate the potential and versatility of electron-capturing NIR luminescent materials in a range of cutting-edge fields.

Multifunctional Phosphor with High-Efficient Near-Infrared Emission Based on Antimony-Zinc Halides.

Metal halide-based broadband near-infrared (NIR) luminescent materials face problems such as complicated preparation, high cost, low photoluminescence quantum yield, and high excitation energy. Here, incorporating Sb3+ and Br- into (C20H20P)2ZnCl4 crystals allowed for the achievement of efficient broadband near-infrared emission under 400 nm excitation while maintaining satisfactory environmental and thermal stability. The compounds exhibit a broad range of emission bands from 550 to 1050 nm, with a photoluminescence quantum yield of 93.57%. This is a groundbreaking achievement for organic-inorganic hybrid metal halide NIR luminescent materials. The near-infrared emission is suggested to originate from [SbX5]2-, as supported by the femtosecond transient absorption spectra and density-functional theory calculations. This phosphor-based NIR LEDs successfully demonstrate potential applications in night vision, medical imaging, information encryption, and anticounterfeiting.

Near-Infrared Luminescent Materials Incorporating Rare Earth/Transition Metal Ions: From Materials to Applications.

The spotlight has shifted to near-infrared (NIR) luminescent materials emitting beyond 1000 nm, with growing interest due to their unique characteristics. The ability of NIR-II emission (1000-1700 nm) to penetrate deeply and transmit independently positions these NIR luminescent materials for applications in optical-communication devices, bioimaging, and photodetectors. The combination of rare earth metals/transition metals with a variety of matrix materials provides a new platform for creating new chemical and physical properties for materials science and device applications. In this review, the recent advancements in NIR emission activated by rare earth and transition metal ions are summarized and their role in applications spanning bioimaging, sensing, and optoelectronics is illustrated. It started with various synthesis techniques and explored how rare earths/transition metals can be skillfully incorporated into various matrixes, thereby endowing them with unique characteristics. The discussion to strategies of enhancing excitation absorption and emission efficiency, spotlighting innovations like dye sensitization and surface plasmon resonance effects is then extended. Subsequently, a significant focus is placed on functionalization strategies and their applications. Finally, a comprehensive analysis of the challenges and proposed strategies for rare earth/transition metal ion-doped near-infrared luminescent materials, summarizing the insights of each section is provided.

Dual substitution of host lattice ions to enhance the luminescence properties of Zn2TiO4:Cr3+ phosphor.

Near-infrared light sources have potential applications in many fields. Cr3+ is a good luminescence centre to prepare near-infrared phosphors. Improving the performance of existing near-infrared luminescent materials has indeed attracted great interest from researchers. The luminescence properties of Zn2TiO4:Cr3+ were improved by crystal field engineering strategies. Zn2+-Ti4+ was partially replaced using a Li+-Nb5+ ion pair based on the Zn2TiO4:Cr3+ phosphors. Luminescence Cr3+-activated luminescent materials are sensitive to changes in the local crystal structure and crystal field environment. Doping of Li+-Nb5+ increased the luminescence intensity up to 2.7 times that of the undoped sample. Also, the thermal stability of the phosphor was greatly increased by the replacement of Li+-Nb5+.

Research progress on Fe3+-activated near-infrared phosphor

Abstract Fe3+-activated near-infrared (NIR) luminescent materials have attracted widespread attention due to their tunable emission wavelength and extensive applications in various fields such as plant growth, food analysis, biomedical imaging, and night vision. Many excellent NIR materials have been developed by introducing non-toxic and environmentally friendly Fe3+ ions into different inorganic hosts. This article elucidates the luminescent properties of Fe3+ ions by combining the Tanabe–Sugano energy level diagram and the configuration coordinate model. The latest research progress on Fe3+-doped NIR luminescent materials is outlined, summarizing the luminescent characteristics of various Fe3+-doped materials, including emission wavelength, emission bandwidth, quantum efficiency, and thermal stability. Particularly, a detailed summary and analysis of the application areas of Fe3+-doped NIR luminescent materials are provided. Finally, the future prospects and challenges faced by Fe3+-doped NIR luminescent materials are presented. This review contributes to a deeper understanding of the luminescence mechanism of Fe3+ and the research progress of iron ion-doped luminescent materials, aiming to develop advanced Fe3+-activated NIR luminescent materials with enhanced performance and explore new application fields.

Long wavelength near-infrared II emitting Na<sub>3</sub>YSi<sub>3</sub>O<sub>9</sub>:<i>x</i> Cr<sup>3+ </sup>silicate and spectral broadening by multi-site occupancy

Phosphors-converted near-infrared LED (pc-NIR LED) possesses applications in various fields including food quality analysis, night vision, biomedical imaging, and biomedicine. The design and development of broadband near-infrared (NIR) phosphors with the required properties are of decisive significance for pc-NIR LED devices. The Cr<sup>3+</sup> doped phosphors are considered to be most promising near-infrared materials for commercialization. Broadband NIR luminescent materials doped with Cr<sup>3+</sup> have attracted more and more attention due to their potential applications in NIR light sources. However, the emission wavelength of Cr<sup>3+</sup> doped phosphor is generally located in the NIR I region of less than 850 nm, and realizing the NIR II region emission is still a challenge. In this work, a series of Cr<sup>3+</sup> doped Na<sub>3</sub>YSi<sub>3</sub>O<sub>9</sub> new silicate phosphors is prepared by solid-state method in N<sub>2</sub> atmosphere at 1150 ℃ for 8 h. We take advantages of the silicate nature and the multi octahedral sites suitable for Cr<sup>3+</sup> in the studied Na<sub>3</sub>YSi<sub>3</sub>O<sub>9</sub> materials to redshift and broaden the spectrum. The phase, crystal structure, microstructure, photoluminescence, main emission peak decay and thermal stability of the samples are systematically studied. The results show that the prepared samples are pure phases, with uneven morphology, slight agglomeration, and the sizes in the micrometer range. The Cr<sup>3+</sup> is located in the weak crystal field environment of Na<sub>3</sub>YSi<sub>3</sub>O<sub>9</sub> lattice, with a <i>Dq</i>/<i>B</i> value of 2.29. Under the excitation of blue light at a wavelength of 485 nm, the strongest emission peaks of Na<sub>3</sub>Y<sub>1–<i>x</i></sub> Si<sub>3</sub>O<sub>9</sub>:<i>x</i> Cr<sup>3+</sup> phosphors are located at 984 nm (NIR II region), which is longer than those of most Cr<sup>3+</sup> activated phosphors. Due to the multi-site occupation of Cr<sup>3+</sup> in the lattice, the full width at half maximum (FWHM) of the emission spectrum is as high as 183 nm. The optimal doping concentration of Na<sub>3</sub>Y<sub>1–<i>x</i></sub> Si<sub>3</sub>O<sub>9</sub>:<i>x</i> Cr<sup>3+</sup> is 3%, and the quenching mechanism is the dipole-dipole interaction between Cr<sup>3+</sup> ions. Fluorescence decay curves show that the luminescence lifetime of Na<sub>3</sub>Y<sub>0.97</sub>Si<sub>3</sub>O<sub>9</sub>:0.03Cr<sup>3+</sup> sample gradually decreases with the increase of doping concentration and temperature. The results of the temperature-dependent spectra show that the emission intensity decreases in a temperature range from 298 K to 423 K, and the activation energy Δ<i>E</i> of Cr<sup>3+</sup> is 0.157 eV.

Tunable broadband near-infrared luminescence from Cr3+-doped gallium oxide-based phosphors for advanced sensing and LED applications

A series of Cr3+-activated near-infrared luminescent materials were successfully prepared by using [Zn2+-Ge4+] and [Ga3+-Ga3+] co-unit substitutions, with the peak luminescence tuned from 713 to 767 nm and the FWHM extended from 92 to 155 nm.

Synthesis of Vis/NIR BOPYINs and their Dual-emission, AIE, and Viscosity Response Properties

Near infrared (NIR) organic dyes with fast fluorescence response in solution, aggregation and solid states are useful in bioimaging field. Here, BOPYIN derivatives featuring electron-donating (triphenylamine) and/or the electron-accepting group (p-cyanophenyl) on BOPYIN core with aggregation-induced emission (AIE), dual-emission, and viscosity response in visible (BOPYIN-1, 3, 5) and NIR (BOPYIN-2, 4, 6, 7, 8) region were synthesized and characterized. Typical dual-emission phenomenon is detected in BOPYIN-2, the fluorescence quantum yields are 40.19 % and 28.5 % in solid and solution state, respectively. BOPYIN-2, 4, 6 show significant increase in fluorescence intensity with the addition of water (AIE). With the increasing of viscosity, the fluorescence intensity increased significantly from 1.79 to 3.54-fold for BOPYIN-3-6, 8. The structure-optical properties relationship was further discussed by single crystals and DFT calculation. We firmly believe that this study will provide guidance for the rational design of versatile NIR luminescent materials.

Selective enrichment strategy induces ultra-broadband NIR emission in Cr3+-doped multi-phase glass-ceramics for NIR spectroscopy applications

Near-infrared (NIR) spectroscopy has gained widespread application in food analysis, disease diagnosis, fingerprint analysis, and security monitoring. However, the lack of efficient, broadband NIR luminescent materials hinders the full potential of this technology. Here, an ultra-broadband and high-efficiency Cr3+-doped multi-phase glass-ceramics containing MgAl2O4, Al2SiO5, and SiO2 nanocrystals was discovered, which exhibited an ultra-broadband NIR emission (λem ∼ 900 nm) with a full width at half maximum more than 300 nm and a high internal quantum yield of 50.9% under the excitation of 465 nm blue light. Moreover, the integrated emission intensity at 100 °C and 150 °C can keep 88% and 77% of that at room temperature. The ultra-broadband, high efficiency, and thermally robust luminescence of this Cr3+-doped multi-phase glass-ceramics can be attributed to the selective enrichment of Cr3+ ions into different nanocrystals with octahedral sites, and medium electron-photon coupling effect. The NIR glass-ceramics-converted light-emitting diode constructed by the glass-ceramics combined with 465 blue LED chip produced an excellent NIR output and photoelectric conversion efficiency of 274 mW/1007 mW and 3.43%/2.79% at 100 mA/320 mA drive current, which demonstrated superior overall performance to the NIR device built by using the well-known NIR phosphors. Additionally, the NIR camera can capture the image of license plate and nectarine, as well as identify the residual drug content in the bottle under the irradiation of the NIR device constructed by the glass-ceramics. This work not only presented an ultra-broadband and high-efficiency NIR material but also highlights a design strategy to effectively enhance the efficiency and broadband characteristics of NIR glass-ceramics.

Effects of Cr3+ content on the structure and fluorescence properties of SiO2–Na2O–Y2O3–P2O5 glasses and glass-ceramics with Na3YSi2O7 crystal phase

In this work, the Cr2O3-doped SiO2–Na2O–Y2O3–P2O5 precursor glasses were prepared by the melt-quenching method. A two-step heat treatment was used to obtain Cr2O3-doped glass ceramics with oxyapatite-silicate-type Na3YSi2O7 crystal phase. The optimum heat treatment schedule was determined to be heat-treated 660 °C/1 h + 760 °C/20 min by XRD and fluorescence spectra. Compared with precursor glasses, the luminescent properties of the Cr2O3-doped glass-ceramics containing Na3YSi2O7 crystals have been greatly improved. The optimum Cr2O3-doping amount was determined to be 0.4 mol%. Under the excitation of 490 nm, the glass-ceramics have a broad emission peak centered at 980 nm in the near-infrared region, which belongs to the 4T2→4A2 transition of Cr3+ ions. This work shows that the Cr2O3-doped glass-ceramic materials have the potential to be used as near-infrared luminescent materials in the fields of illumination display, bio-fluorescence imaging, solar cells, etc.

Multiple defects induced near-infrared self-luminescence of (Ca,Sr)LaMgTaO6 double perovskite phosphor

Conventional near-infrared luminescent phosphors activated by transition metal elements or rare earth activators were already widely reported. In this work, we develop a self-activated near-infrared luminescent phosphor with a typical double perovskite structure, which exhibits an emission at 650–750 nm under excitation at 365 nm. The origin of the desired luminescence in (Ca,Sr)LaMgTaO6 compounds is attributed to the oxygen vacancies defects, oxygen interstitial defects and substitution defects and antioccupation defects. Thermal quenching of photoluminescence is undesirable with an integrated emission loss of 30–50% at 150 °C, which needs to be improved. This new series of near-infrared luminescent materials have potential applications in agricultural cultivations and bio-imaging materials. More importantly, we demonstrate a strategy by self-activation to realize near-infrared light.

Full Solution Process of a Near-Infrared Light-Emitting Electrochemical Cell Based on Novel Emissive Ruthenium Complexes of 1,10-Phenanthroline-Derived Ligands and a Eutectic Alloy as the Top Electrode

Near-infrared luminescent materials have recently received considerable attention for a large number of applications, including in solid-state lighting, as bioimaging agents, as photovoltaic cells, and in the telecommunication industry. By adding diverse electron-donating or withdrawing groups on ancillary ligands based on benzenethiol-phenanthroline, we synthesized and optoelectronically characterized a series of novel ionic ruthenium complexes, namely RuS, RuSCl, RuSMe, and RuSNH2, for using in a light-emitting electrochemical cell. The synthesized complexes are intense red emitters in the range of 584–605 nm in solution, which depends on the substitutions of electron donor/acceptor moieties on the ancillary ligands. To find a suitable quantum mechanical approach, benchmark calculations based on time-dependent density functional theory were carried out on these complexes. Our benchmark revealed that the M06-L method has results close to those of the experiment. Furthermore, to gain a deeper insight into electronic transitions, several excitation processes were investigated at the TD-DFT-SMD-MN12-L/gen level. The results showed that in the designed complexes, the dominant transition is between the 4dZ2 electron of Ru (particle) and the π* orbitals of the ancillary ligand (hole). The single-layer devices, including these complexes along with a Ga/In cathode by a facile deposition method without the addition of any electron or hole transport layers, were fabricated and displayed red (678 nm) to near-infrared (701 nm) emission as well as a decrease of turn-on voltage from 3.85 to 3.10 V. In particular, adding a methyl group to the ancillary ligand in the complex RuSNH2 increases the external quantum efficiency to 0.55%, one of the highest observed values in the ruthenium phenanthroline family. This simple structure of the device lets us develop the practical applications of light-emitting electrochemical cells based on injection and screen-printing methods, which are very promising for the vacuum-free deposition of top electrodes.

Highly efficient visible and near-infrared luminescence of Sb3+, Tm3+ co-doped Cs2NaYCl6 lead-free double perovskite and light emitting diodes

Near-infrared (NIR) luminescent materials have been widely used in biomedicine, optical communication and other fields due to their unique photophysical properties. However, the development of efficient NIR luminescent materials is still a challenge. Herein, Sb3+, Tm3+ co-doped Cs2NaYCl6 double perovskite single crystals (SCs) have been synthesized. Benefiting from the crystal structure and rare earth lattice of rare earth-based double perovskite host, lanthanide ions can be doped effectively, and the optimal NIR photoluminescence quantum yield (PLQY) of Cs2NaYCl6:Sb3+, Tm3+ SCs is up to 20.2%. The energy transfer mechanism was systematically surveyed by steady-state spectroscopy. Furthermore, a compact visible and NIR light emitting diode was fabricated by coating Cs2NaYCl6:Sb3+, Tm3+ SCs on a commercial 320 nm LED chip. This light source has a promising application prospect in multifunctional lighting.

Ion Substitution Strategy toward High-Efficiency Near-Infrared Photoluminescence of Cs2KIn1–yAlyF6:Cr3+ Solid Solutions

The rising demand for portable near-infrared (NIR) light sources has accelerated the exploration of NIR luminescent materials with high efficiency and excellent thermal stability. Inspired by the structural-modulated ion substitution strategy, herein, a high-performance Cs2KIn0.8Al0.1F6:0.1Cr3+ phosphor with a peak at 794 nm and full width at half-maximum (fwhm) of 117 nm was successfully synthesized by introducing Al3+ ions. The high performance is reflected in its high internal quantum efficiency (IQE) of 88.06% and good thermal quenching resistance (I423K = 71.64%). Compared with the initial Cs2KInF6:0.1Cr3+, the IQE and thermal stability are improved by 16.67% and 72.54%, which stem from the enhanced crystallinity and the strengthened structural rigidity. Finally, a phosphor-converted light-emitting diode (pc-LED) with a superior NIR photoelectric efficiency (21.04%@320 mA) was fabricated. Meanwhile, the pupil tracking, anticounterfeiting, intelligent identification, and bioimaging were successfully demonstrated. This work provides new perspectives for synthesizing efficient NIR fluoride phosphors and designing diverse applications.

Single‐Site Occupancy of Eu2+ in Multiple Cations Enables Efficient Ultra‐Broadband Visible to Near‐Infrared Luminescence

AbstractAn important challenge in the research and development of compact near‐infrared (NIR) light sources is the discovery of new efficient ultra‐broadband NIR luminescent materials to replace the conventional Cr3+‐doped compounds. Herein, this work reports a divalent europium‐doped Ba3GeO4Br2 phosphor that exhibits a high photoluminescence quantum yield of 48.8% and an ultra‐broad emission band ranging continuously from 500 to 1100 nm (full width at half maximum = 202 nm) under near‐ultraviolet or blue light excitation. A strategy of embedding alumina crucible in high purity graphite crucible is devised and deployed during solid‐state sintering to facilitate the conversion of Eu3+ into Eu2+. Theoretical calculations, structural refinement, and spectral analysis demonstrate that the visible to NIR emission in Ba3GeO4Br2:Eu2+ originates from the Eu2+ ions occupying the distorted Ba3O3Br4 polyhedra in the lattice. The as‐prepared phosphor‐converted light‐emitting diode device achieves an optical output power of 30.1 mW@100 mA (520–1100 nm) and a photoelectric efficiency of 22%@100 mA (350–1100 nm). Experiments on tissue penetration and NIR imaging illustrate its application in spectral detection and food quality testing appears promising.

LaMgGa11O19:Cr3+,Ni2+ as Blue‐Light Excitable Near‐Infrared Luminescent Materials with Ultra‐Wide Emission and High External Quantum Efficiency

AbstractHighly efficient luminescence material covering near‐infrared (NIR) I (700–1000 nm) and II (1000–1700 nm) is of great importance for phosphor‐converted NIR light‐emitting diodes (pc‐LEDs) light sources. The lack of ultra‐wide emission NIR luminescent materials that can be excited by cheap blue‐LEDs, suspends the applications of NIR pc‐LEDs. Ni2+‐activated phosphor usually gives an NIR‐II region emission, however, it presents low quantum efficiency due to poor absorption in blue light region. Here, a blue‐LED‐excitable (400–480 nm) LaMgGa11O19(LMG):Cr3+,Ni2+ NIR‐emitting phosphor is reported. Significantly, by constructing energy transfer from Cr3+ to Ni2+, it demonstrates an ultra‐wide NIR emission from 650 to 1600 nm, and greatly improves external quantum efficiency (EQE) from 2% to 53%. Besides, the weakened exchange coupling of Ni2+−Ni2+ pairs leads to an abnormal blue‐shift of Ni2+ emission with increasing temperature. The fabricated NIR pc‐LED gives a high output power of 8 mW at 20 mA with the photoelectric efficiency of 14%, which favors potential applications in night‐vision technology, medical applications, non‐destructive analysis, and spectroscopic analysis. This exploration of Cr3+‐Ni2+ co‐doped strategy for realizing high‐performance NIR‐emitting phosphor provides novel and effective design insights into developing more ultra‐broadband NIR pc‐LEDs based on cheap blue LEDs.

The broadband emission of Cr3+-doped CaY2Mg2Ge3O12 and its applications for NIR detectors.

A phosphor-converted light-emitting diode (pc-LED) is a prime light source in smart broadband near-infrared (NIR) spectroscopy. The performance of NIR pc-LEDs crucially depends on the employed NIR luminescent materials. In this study, we synthesized a novel high-efficiency broadband NIR phosphor, CaY2Mg2Ge3O12:Cr3+ (CYMG:Cr3+). Under 450 nm excitation, CYMG:Cr3+ exhibited remarkable broadband NIR emission from 650 to 900 nm with a full width at half maximum (FWHM) of 115 nm. Within the CYMG lattice, the Cr3+ ion occupies Ca/Y sites in the dodecahedron Ca/YO8 and Mg sites in the octahedron MgO6, giving rise to two distinct Cr3+ luminescence centers. Remarkably, the emission at 100 °C remained at 92% of its room temperature intensity and 81% at 150 °C, showcasing its exceptional thermal stability. The internal quantum efficiency (IQE) reached an impressive 81.1%, with an activation energy ΔE of 0.324 eV. Furthermore, we integrated the CYMG:Cr3+ phosphor with a commercial 450 nm blue chip to fabricate a micro NIR pc-LED, which exhibited stable NIR emission across different driving currents, with a NIR output power of 49.65 mW@400 mA and a photoelectric conversion efficiency of 10.52% at 20 mA. All findings highlight CYMG:Cr3+ as a stable and efficient broadband luminescent material for high-performance NIR LEDs.