High Output Power and High Quantum Efficiency in Novel NIR Phosphor MgAlGa0.7B0.3O4:Cr3+ with Profound FWHM Variation

Cr 4+ -activated phosphors are important candidate materials for NIR-II light sources, but providing a suitable lattice coordination environment for Cr 4+ and achieving long wavelength broadband emission remains a challenge. In this work, a series of Cr 4+ -activated ABO 2 (A = Li, Na; B = Al, Ga) phosphors were successfully prepared. Due to the presence of only tetrahedral coordination structures available for Cr 4+ to occupy in the matrix crystal ABO 2 , the valence state and luminescence stability of Cr 4+ are effectively guaranteed. Through the cation substitution design of A-site (Na → Li) and B-site (Ga → Al), the [BO 4 ] tetrahedron is distorted and expanded, which degrades the symmetry of the Cr 4+ coordination crystal field. Consequently, the central wavelength of the Cr 4+ emission peak is tuned from 1280 to 1430 nm, and the fwhm is significantly extended from 257 to 355 nm. Thebroadband NIR-II light sources constructed with LiAlO 2 : 0.03Cr 4+ and NaGaO 2 : 0.03Cr 4+ phosphors verify their important potential applications in nondestructive testing and biological imaging.

Section: Introductionmentioning

confidence: 99%

Realizing Ultrabroadband NIR-II Emission and Wide-Range Wavelength Tuning in Cr⁴⁺-activated ABO₂ (A = Li, Na; B = Al, Ga) Phosphors

Yang,

Zou,

et al. 2024

“…Near-infrared (NIR) emission materials play a pivotal role in numerous fields, including biomedical imaging for disease diagnosis and treatment monitoring, photodynamic therapy for cancer treatment, nondestructive inspection for quality control in manufacturing, night vision systems for enhanced security and surveillance, and X-ray imaging . However, to meet the increasing demand for its practice applications, the development of efficient, compact, and broadband NIR emission light sources is essential. , Among diverse NIR emission materials, inorganic phosphor materials offer a high quantum efficiency, stability, tunable emission wavelengths, compatibility with optical detection systems, versatility, and cost-effectiveness, making them ideal matrixes for developing efficient and diverse NIR emissions to fulfill the evolving requirements of the corresponding applications. − Here, constructing a broadband NIR phosphor with a high thermal stability is the top priority to address these requirements and drive progress in the field. , …”

Section: Introductionmentioning

confidence: 99%

“…5 However, to meet the increasing demand for its practice applications, the development of efficient, compact, and broadband NIR emission light sources is essential. 6,7 Among diverse NIR emission materials, inorganic phosphor materials offer a high quantum efficiency, stability, tunable emission wavelengths, compatibility with optical detection systems, versatility, and cost-effectiveness, making them ideal matrixes for developing efficient and diverse NIR emissions to fulfill the evolving requirements of the corresponding applications. 8−11 Here, constructing a broadband NIR phosphor with a high thermal stability is the top priority to address these requirements and drive progress in the field.…”

Section: ■ Introductionmentioning

confidence: 99%

Crystal Field-Engineered Cr³⁺-Doped Gd₃(Mg_xGa_5–2xGe_x)O₁₂ Phosphors for Near-Infrared LEDs and X-ray Imaging Applications

Zeng,

Liu,

Zeng

et al. 2024

Inorganic materials doped with chromium (Cr) ions generate remarkable and adjustable broadband near-infrared (NIR) light, offering promising applications in the fields of imaging and night vision technology. However, achieving high efficiency and thermal stability in these broadband NIR phosphors poses a significant challenge for their practical application. Here, we employ crystal field engineering to modulate the NIR character-T h e Gd 3 Mg x Ga 5−2x Ge x O 12 (GMGG):7.5% Cr 3+ (x = 0, 0.05, 0.15, 0.20, and 0.40) phosphors with NIR emission are developed through the cosubstitution of Mg 2+ and Ge 4+ for Ga 3+ sites. This cosubstitution strategy also effectively reduces the crystal field strength around Cr 3+ ions, which results in a significant enhancement of the photoluminescence (PL) full width at half-maximum (fwhm) from 97 to 165 nm, alongside a red shift in the PL peak and an enhancement of the PL intensity up to 2.3 times. Notably, the thermal stability of the PL behaviors is also improved. The developed phosphors demonstrate significant potential in biological tissue penetration and night vision, as well as an exceptional scintillation performance for NIR scintillator imaging. This research paves a new perspective on the development of high-performance NIR technology in light-emitting diodes (LEDs) and X-ray imaging applications.

“…Also, many Cr 3+ -doped phosphors that have been studied can be excited well by blue light chips and emit NIR light efficiently, such as GaTaO 4 :Cr 3+ with an internal quantum efficiency (IQY) as high as 91.2% and a FWHM of 140 nm, and Mg 7 Ga 2 GeO 8 :Cr 3+ maintained a high IQY (92%) while demonstrating a wide FWHM (226 nm) . A novel MgAlGa 0.7 B 0.3 O 4 :Cr 3+ phosphor obtained by substituting Ga with B has achieved a breakthrough of 65% in external quantum efficiency (EQY), exhibiting an excellent NIR luminescence performance . Although there are many high-performance Cr 3+ -doped phosphors, their emission bands are in the NIR-I region (780–1000 nm).…”

Section: Introductionmentioning

confidence: 99%

Multifunctional Near-Infrared Phosphors Cr³⁺/Ni²⁺ Codoped Mg₃Ga₂GeO₈ Based on Energy Transfer from Cr³⁺ to Ni²⁺

Wang,

Niu,

Wang

et al. 2024

Currently, near-infrared (NIR) light-emitting materials have been widely used in many fields, such as night vision, bioimaging, and nondestructive analysis. However, it is difficult to achieve multifunction in certain NIR light emitting phosphor. Herein, we propose a new near-infrared phosphor Mg 3 Ga 2 GeO 8 :Cr 3+ ,Ni 2+ that can be applied to at least three fields, i.e., identification of compounds, temperature sensing, anticounterfeiting, and other applications. The multifunctional material exhibited efficient broadband emission of 650−1650 nm under 420 nm excitation. The emission intensity of Ni 2+ in Mg 3 Ga 2 GeO 8 :Cr 3+ ,Ni 2+ is enhanced by two times compared with that of Ni 2+ in Mg 3 Ga 2 GeO 8 :Ni 2+ due to the energy transfer process. Compared with phosphor single doped with Ni 2+ , Mg 3 Ga 2 GeO 8 :Cr 3+ ,Ni 2+ is more convincing in organic compound recognition because it is based on two emission bands: 600−1100 nm and 1100−1650 nm. As a temperature sensor, Mg 3 Ga 2 GeO 8 :Cr 3+ ,Ni 2+ is an ideal temperature-sensing material. This work not only provides a super broadband NIR emitting phosphor with multiple functions but also presents a practical approach for the development of high-efficiency and multifunctional NIR phosphors.