700-1100 nm range to obtain more effective information in practical application such as food analysis, medical diagnostics, and agricultural science. [5][6][7][8] On the other hand, integrating the NIR spectroscopy into mobile phones or wearable devices are emerging demand that call for NIR light source with small size. [9,10] The traditional tungsten-halogen lamps or supercontinuum lasers cannot meet these new applications because of their large size, short lifetime, and poor efficiency. [11,12] NIR light emitting diodes (LEDs) show the advantages of small size, but their emission bandwidth is less than 50 nm, which is too narrow. [13,14] In this context, phosphor-converted LEDs (pc-LEDs) with broad NIR emission were recently proposed, where one or more kinds of NIR phosphors were coated on a blue LED chip. The broad and tunable emission band as well as the small size of such NIR pc-LEDs make them an excellent alternative light source for miniature NIR spectroscopy applications.The NIR phosphor acts as a key role to convert blue light from LED chip to broadband NIR light. [15] Thus, many efforts have been made to explore NIR phosphors with broad emission band and high efficiency, such as K 3 LuSi 2 O 7 :Eu 2+ (740 nm), [16] CaS:Eu 2+ ,Tb 3+ (810 nm) [17] and Lu 2 BaAl 4 SiO 12 :Ce 3+ ,Mn 2+ (770 nm). [18] The main drawbacks of that Eu 2+ /Ce 3+ activated phosphor are their relatively short emission wavelength (<850 nm), low internal quantum efficiency (IQE), and poor thermal stability. Thus, Cr 3+ -activated NIR phosphors draw more attention for their broad emission bandwidth and high efficiency. [19,20] For example, Song et al. reported K 2 NaScF 6 :Cr 3+ NIR phosphor with an emission band peaking at 765 nm and IQE of 74%. [21] Zheng and co-workers designed Y 2 CaAl 4 SiO 12 :Cr 3+ translucent ceramics by cation co-substitution of Ca 2+ -Si 4+ for Y 3+ -Al 3+ and achieved high IQE (90.1%) and external QE (EQE) (59.5%). [22] Highly efficient NIR emissions have also been reported in other phosphors such as Ca 2 LuHf 2 Al 3 O 12 :Cr 3+ (775 nm), [4] La 2 MgZrO 6 :Cr 3+ (825 nm), [10] Ga 2 O 3 :Cr 3+ (740 nm), [23] GdAl 3 (BO 3 ) 4 :Cr 3+ (733 nm), [24] LaMgGa 11 O 19 :Cr 3+ (770 nm) [25] and so on. Though the above NIR phosphors have high IQE and excellent thermal stability, they also suffer from deficient emission in 850-1100 nm, which limits their practical applications. Some NIR phosphors with longer wavelength emission (>850 nm), such as La 3 Ga 5 GeO 14 :Cr 3+ (920 nm), [26] ZnTa 2 O 6 :Cr 3+ (935 nm), [27] and LiIn 2 SbO 6 :Cr 3+ (965 nm), [28] were reported, but their IQEs are Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are an emerging light source demanded for the miniaturization of NIR spectroscopy. However, the photoelectric efficiency and spectral properties of NIR pc-LEDs are still very limited due to a lack of efficient broadband NIR phosphors with peak emission wavelength >850 nm. Here, a novel Cr 3+ -activated perovskite-like Mg 4 Ta 2 O 9 phosphor is reported, which exhib...