Currently, NIR analysis and detection are mainly concentrated on large-scale equipment, which is not conducive to daily use. In order to achieve the practicability and convenience of optical-electronic products, smart NIR light sources have been proposed for intelligent devices, especial the smart phone, to detect the freshness and safety of food. [7] It is essential to find a new NIR light source with high efficiency and broadband emission for these applications. Compared with the traditional NIR light source (i.e., tungsten halide lamps and laser diodes), the NIR phosphorconverted light-emitting diodes (pc-LEDs) are prepared by combining broadband NIR phosphors and blue LED chips, which have the advantages of smaller size and longer life. [8,9] Therefore, developing a broadband NIR phosphor that can be effectively excited by the blue light is the top priority for many applications.Activators excited by the blue light in NIR phosphors are mainly rare-earth and transition metal ions. Eu 2+ is a candidate, which shows broad NIR light with a peak at 740 nm and a full width at half maximum (FWHM) of 160 nm in K 3 LuSi 2 O 7 , while the intensity at 150 °C is only 59% of that at room temperature. [10] In addition to the lower thermal stability, NIR emission from rare-earth ion single-doped phosphors are often to obtain high efficiency. [11,12] On the contrary, the NIR phosphor doped with transition metal ions is easy to obtain broadband emission with good thermal stability. Cr 3+ is one of transition metal ions with 3d 3 electronic configuration, and the shell does not shield the three valence electrons. The spatial expansion of the d-electron wavefunction will be strongly interacted by the crystal field and lattice vibrations. Therefore, the Cr 3+ ions are very sensitive to the crystal field, which can be exploited to obtain NIR phosphors with high thermal stability and broadband emission by changing the crystal field environment. [13] Furthermore, the d-d transition of Cr 3+ ions usually shows a vast emission peak and absorption peak, and there is a significant absorption in the blue light. Thus, NIR phosphors doped with Cr 3+ ions have been studied widely. [14][15][16][17][18] Cr 3+ often occupies octahedrons or tetrahedrons sites in germanate NIR phosphors with wide FWHM. [19][20][21] Although the NIR phosphor based on germanate has a comprehensive emission spectrum, the low quantum Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have promising applications in food analysis, night vision imaging, and biological probes. Developing NIR phosphors with broadband emission and high efficiency has attracted immense interest. Herein, a novel NIR phosphor Ca 2 LuScAl 2 Si 2 O 12 :Cr 3+ (CLSAS:Cr 3+ ) is reported for the first time. Under the excitation of 442 nm light, CLSAS:Cr 3+ shows broadband emission from 600 to 900 nm with a full width at half maximum (FWHM) of 142 nm, benefiting from the emissions of two Cr 3+ centers in CLSAS, which is proved by the spectra and the decay curves. The internal q...
