Crystal‐Field Engineering Control of an Ultraviolet–Visible‐Responsive Near‐Infrared‐Emitting Phosphor and Its Applications in Plant Growth, Night Vision, and NIR Spectroscopy Detection

Abstract Broadband near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) have many prospective applications in areas related to food inspection, health management, plant growth, and night vision, because NIR phosphors are critical components of the corresponding devices. Given the wide‐ranging applicability of the material, this study is designed to comprehensively evaluate a series of novel NIR phosphors: BaMgGa x Al 10– x O 17 :Cr 3+ ( x = 0, 1, 2, 3). The ultra‐low‐temperature (4 K) fluorescence spectroscopy and decay curve results confirm that Cr 3+ occupies the four lattice sites of Al 3+ in the matrix. Additionally, the introduction of Ga 3+ increases the full‐width at half‐maximum (FWHM) of the NIR spectrum from 100 to 300 nm without affecting the fluorescence efficiency; it also considerably increases spectral coverage. An experiment to evaluate the applicability of the novel NIR phosphors reveals that the sunlight‐converting film prepared by applying the material combination of BaMgGa 3 Al 7 O 17 :0.02Cr 3+ is able to effectively promote the growth of Chlorella. In addition, the NIR pc‐LED with a BaMgGa 3 Al 7 O 17 :0.2Cr 3+ basis and 395‐nm LED chip has been proven to be an excellent candidate for applications in NIR spectral detection and night‐vision technology.