Enhancement of Near‐Infrared Phosphor Luminescence Properties via Construction of Stable and Compact Energy Transfer Paths

Abstract The rapid development of near‐infrared (NIR) spectroscopy urgently requires the exploration of NIR‐emitting phosphors with excellent luminescence properties. Herein, GaTaO₄:Cr³⁺,Yb³⁺ NIR phosphor with excellent luminescence properties is reported, which exhibits ultra‐broadband NIR emission with a full width at half maximum of 300 nm, good thermal stability of 90%@423 K, and most remarkably, high internal quantum efficiency of 95.5% and external quantum efficiency of 44.79%. Such outstanding luminescence properties mainly give the credit to the unique sandwiched structure of GaTaO₄:Cr³⁺,Yb³⁺, in which layers of Yb³⁺ ions (activator) are sandwiched between layers of Cr³⁺ ions (sensitizer), and hence many stable and compact Cr–Yb pairs are formed, so that the energy can be rapidly transferred from Cr³⁺ to Yb³⁺, effectively activating the characteristic f–f transition of Yb³⁺ that is very stable and almost independent of the temperature, and at the same time, the non‐radiative transition of Cr³⁺ ions can be suppressed to a certain degree. The NIR phosphor‐converted light‐emitting diodes (pc‐LEDs) are fabricated by combining GaTaO₄:Cr³⁺,Yb³⁺ with blue LED chips, and the application potential is fully demonstrated by non‐destructive food detection, night vision, and vein display. The results provide novel prospects for the design of NIR‐emitting materials with desirable luminescent properties.