Ni²⁺-Doped Garnet Solid-Solution Phosphor-Converted Broadband Shortwave Infrared Light-Emitting Diodes toward Spectroscopy Application

Abstract

Broadband shortwave infrared (SWIR) light-emitting diodes (LEDs), capable of advancing the next-generation solid-state smart invisible lighting technology, have sparked tremendous interest and will launch ground-breaking spectroscopy and instrumental applications. Nevertheless, the device performance is still suppressed by the low quantum efficiency and limited emission bandwidth of the critical phosphor layer. Herein, we report a high-performance Ni2+-doped garnet solid-solution broadband SWIR emitter centered at ∼1450 nm with a large full-width at half-maximum of ∼300 nm, thereby fabricating, for the first time, a directly excited Ni2+-doped garnet solid-solution phosphor-converted broadband SWIR LED device. A synergetic enhancement strategy, adding a fluxing agent and a charge compensator simultaneously, is proposed to deliver a more than 20-fold increase of the SWIR emission intensity and nearly 2-fold improvement of the thermal quenching behavior. The site occupation and mechanism behind the synergetic enhancement strategy are elucidated by a combination of experimental study and theoretical calculation. A prototype of the SWIR LED with a radiation flux of 1.25 mW is fabricated and utilized as an invisible SWIR light source to demonstrate the SWIR spectroscopy applications. This work not only opens a window to explore novel broadband SWIR phosphors but also provides a synergetic strategy to remarkably improve the performance of artificial SWIR LED light sources.

Achieving a near-unity quantum yield from yellow emitting metal halide double perovskites toward human-centric warm white LED lighting

“…As shown in Fig. 2F, it can be well fitted using the following formula: 30,31 It has been reported that the triplet STEs have lifetimes ranging from about 90 ns to 5 ms in alkali halides. 32 Initially, the free electrons and holes were excited to form excitons and then transition to the self-trapped state, resulting in radiation recombination.…”

Crystallographic control for Cr4+ activators toward efficient NIR-II luminescence

“…As the key component, NIR phosphors activated by transition metal ions (Cr 3+ , Ni 2+ , Mn 2+ and Mn 4+ ) and rare earth ions (Eu 2+ , Pr 3+ , Yb 3+ , and Tm 3+ ) have been developed in recent years. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Among them, Cr 3+ activated NIR phosphors show an outstanding performance and many efficient phosphors have been developed recently. For example, Liu et al synthesized the NIR phosphor SrGa 12 O 19 :Cr 3+ with an external quantum efficiency of 45%.…”

Broadband near-infrared luminescence from Fe3+-activated NaScSi2O6 phosphors for luminescence thermometry and night-vision applications

“…Several other TM ions also show intense NIR emission. [9][10][11] One of the promising and so far scarcely investigated candidates is the eco-friendly and chemically stable Fe 3+ ion, which is of d 5 electronic configuration and was previously considered a luminescence quencher in optical spectroscopy. It is found that when Fe 3+ is doped into diverse hosts, it could exhibit NIR photoluminescence with an emission band in the 700-1000 nm range due to its 4 T 1 -6 A 1 transition.…”