Work

Overcoming Rigidity‐Flexibility Constraints in Garnet Phosphors for Broadband and Thermally Stable NIR Emission

Year: 2026

Type: article

Abstract: ABSTRACT Achieving near‐infrared (NIR) phosphors with broadband emission, robust thermal stability, high internal quantum efficiency (IQE), and excellent chemical durability remains a longstanding challenge, largely due to the fundamental trade‐off between structural rigidity and flexibility. Here, we overcome this constraint by designing a novel series of garnet‐type phosphors, BaY 2 Ga 4‐ x GeO 12 : x Cr 3+ (BYGG: x Cr 3+ ). The optimized composition BYGG:0.06Cr 3+ delivers an IQE of 93%, remarkable anti‐thermal quenching behavior (103% emission retention at 423 K), and outstanding chemical stability (retaining 97% emission after 35 days in water). Notably, fine‐tuning the Cr 3+ concentration broadens the emission bandwidth from 77 to 194 nm while preserving strong thermal stability (93%@423 K). This exceptional performance arises from the synergistic combination of ultra‐high structural rigidity (Debye temperature, Θ D = 987 K), wide bandgap (5.10 eV), weak crystal field strength, and optimized 4 T 2 excited‐state population. A fabricated NIR phosphor‐converted LED (pc‐LED) device demonstrates an NIR radiated power of 189.35 mW at 100 mA and a photoelectric conversion efficiency up to 12%. These results establish NIR phosphor BYGG: x Cr 3+ as a promising candidate for next‐generation NIR pc‐LED applications in night vision, non‐destructive inspection, and biomedical imaging.

Source: Laser & Photonics Review

DOI: 10.1002/lpor.202502789