Super broadband near-infrared phosphors with high radiant flux as future light sources for spectroscopy applications

Abstract

The near-infrared (NIR) light source is desirable for real-Time nondestructive examination applications, which include the analysis of foodstuffs, health monitoring, iris recognition, and infrared cameras. The emission spectra of such an infrared light source should also be as broad as possible for effective performance, in view of the fact that the broad absorption and reflection of light by the organic elements present in foodstuffs and human health fall in the blue and NIR regions of the electromagnetic spectrum, respectively. In this letter, a blue light-emitting diode (LED) excitable super broadband NIR phosphor light source is developed with a high fwhm of 330 nm and radiant flux of 18.2 mW for the first time. The observation of super-broad-band luminescence from two distinct luminescence centers is studied and evidenced by electron paramagnetic resonance, X-ray absorption near-edge structure, steady-state luminescence, and time-resolved luminescence at ambient and high-pressure environments. Finally, the luminescence mechanism is discussed with the relevant configurational coordinate diagrams.