Tailoring the Cr³⁺ Emission via Combinatorial Management of Crystal‐Field and Energy Transfer for Multiple NIR LEDs

Abstract

Near‐infrared (NIR) phosphors converted light‐emitting diodes (NIR pc‐LEDs) are ideal NIR sources for versatile applications, which imply the practical significance in tailoring the emission of the NIR phosphors to enhance the performance for specific application. Herein, a paradigm of tailoring the emissions in a series of Cr3+‐doped phosphors to match the applications in NIR lighting, detection, and short‐wave infrared sources through combinatorial management of crystal‐field and energy transfer is presented. The emission band largely increases from 84 to 190 nm when the introduction of [MgO6]‐[GeO4] into Y3Ga5O12:0.08Cr3+ forms Y3MgxGa5‐2xGexO12:0.08Cr3+ through the substitution of [GaO6]‐[GaO4]. Such a large increase in width makes it suitable for near‐infrared lighting to near‐infrared detection. Moreover, the Yb3+, Nd3+ and Er3+ are doped to construct energy transfer with Cr3+, broadening the emission infrared region and enhanced thermal stability. An optimized Yb3+ emission dominates Y3Ga5O12:0.4Cr3+,Yb3+ phosphor has excellent thermal stability (129%@423 K) and is suitable for high‐power short‐wave infrared sources. The presented work not only provides a series of well‐performed NIR phosphors, but only lights up the avenue for designing the Cr3+ emission for specific application.

Blue light-excited broadband NIR-II-emitting Li2ZnSn3O8:Cr3+,Ni2+ phosphor for multifunctional optical applications

“…Hence, estimating the change in the emission intensity provides a more accurate estimation of ET efficiency. 44 This phenomenon also occurs in Sr 2 GaTaO 6 :Cr 3+ ,Ni 2+ and other ET systems of Cr 3+ → Yb 3+ , Ce 3+ /Eu 2+ → Mn 2+ . [44][45][46] The ET process from Cr 3+ to Ni 2+ is shown in Fig.…”

“…44 This phenomenon also occurs in Sr 2 GaTaO 6 :Cr 3+ ,Ni 2+ and other ET systems of Cr 3+ → Yb 3+ , Ce 3+ /Eu 2+ → Mn 2+ . [44][45][46] The ET process from Cr 3+ to Ni 2+ is shown in Fig. 2f.…”

Achieving Ultrahigh Thermal Stability in Cr3+-Activated Garnet Phosphors through Electron Migration between Thermally Coupled Levels

“…To improve the thermal stability of Cr 3+ -based NIR phosphors, many strategies have been tried. , For example, the replacement of large ion with a small one will be conductive for the tightened crystal structure and optimized thermal stability. , The structural rigidity of CaSc 1– x Al 1+ x SiO 6 : Cr 3+ is strengthened when Sc 3+ is replaced by Al 3+ , thus leading to a suppressed nonradiative relaxation process of Cr 3+ and improved thermal stability . Nevertheless, the effect of this strategy is sometimes far from enough, and a decreased PL intensity is still observed at high temperatures.…”