Crystallization of Na₂SrGe₆O₁₄:Cr³⁺,Yb³⁺ Glass Ceramics Enabling a Watt‐Level Output Power NIR‐I/NIR‐II Lighting Source

Abstract

Near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) lighting sources are applied in non‐destructive examination and illumination supplements for night monitoring. As a critical component of NIR pc‐LED, NIR phosphors are required to possess a high external quantum efficiency (EQE), super thermal stability, and broadband emission to meet applications. Here, Na2SrGe6O14:Cr3+ (NSGO:Cr) glass ceramics (GC) bulk via highly crystallization from glass precursor is fabricated and demonstrates an ultrabroad emission band centered at 815 nm with a full width at half‐maximum (FWHM) of 214 nm and a high EQE of 49.2%. Moreover, Yb3+ co‐doping significantly enhances Cr3+ → Yb3+ energy transfer (ET) due to the stronger Yb3+: 2F7/2‐2F5/2 absorption. Benefiting from the ET process, the Cr/Yb co‐doped GC exhibits NIR‐I/II emission with improved thermal stability from 30.1% to 65.0%. Furthermore, an encapsulant‐free NIR GC‐converted LED (GCc‐LED) is prepared and exhibits 52.2 mW NIR output power with a high photoelectric conversion efficiency (PCE) of 19.4%. Under a large current of 600 mA, the NIR device exhibits a watt‐level output power of 922.4 mW with a PCE of 9.1%. Compared to conventional NIR powder phosphors, NSGO:Cr/Yb GC with high performance can open up an avenue for the fabrication of high power NIR lighting sources.

Hydrothermal and anion exchange synthesis of Mn(v)-doped Ba5(PO4)3Cl nano-apatite toward NIR-II temperature sensing

“…The bands observed at 3400–3600 cm −1 and 1400–1600 cm −1 correspond to the O–H stretching and H–O–H bending vibrations of adsorbed water on the sample surface. 8,25 Furthermore, the absorption band of MnO 4 3− at 700–870 cm −1 aligns with the literature findings. 17,26 Fig.…”

“…As a result, they are popular for both telecommunication and biological applications. 7–10 As a well-known luminescent center, manganese ions exhibit multiple oxidation states including +2, +3, +4, +5 and +6. Among them, Mn 2+ and Mn 4+ are widely used due to their stability and tunable green–orange–red emission in various compounds.…”

Highly efficient and thermostable far-red phosphor for promoting root growth in plants

“…In previous studies, it has been found that introducing Cr 3+ , 14 Fe 3+ , 15,16 Ni 2+ , 17,18 Bi 2+ , 19,20 Eu 2+ , 21,22 and Yb 3+ 23,24 ions in inorganic materials can produce near-infrared photoluminescence. Among these potential candidates, Cr 3+ has become a popular far-red emitting activator applied in plant growth, as it can not only be excited efficiently by blue-violet light but also its emission can be controlled by the crystal field strength.…”

Sharp-to-Broad Band Energy Transfer in Lithium Aluminate and Gallate Phosphors for SWIR LED

“…In recent years, short wavelength study has become popular because of its high penetration power and characteristic absorption signal. Specifically, those capable of emitting light in the short wavelength infrared (SWIR) range of 1000–1700 nm are increasingly essential for advanced technological applications. − This spectral region, often called the “eye-safe” region, is also crucial for light detection and ranging (LiDAR) applications where safety considerations for incidental human exposure are vital. − In biomedical diagnostics, emissions beyond 1000 nm allow for deeper tissue penetration with reduced scattering, enhancing the capabilities of non-invasive optical imaging and improving diagnostic accuracy. − …”