Broadband near-infrared luminescence in the NaAlP2O7:Cr3+ phosphor for spectroscopy applications

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) has demonstrated its advantages of convenience, fast, and non-destructive in spectroscopy applications. As a crucial component of NIR pc-LED, the NIR phosphor is required to be efficient, and inexpensive. However, most of the currently developed NIR phosphors contain the expensive elements. Herein, an efficient, thermally stable, and inexpensive NaAlP2O7:Cr3+ broadband NIR phosphor was synthesized. The crystal and electronic structures were analyzed, as well as the luminescent and fabrication properties were investigated. The results show that the emission spectra of this material covers 700–1100 nm with a peak locating at 790 nm under 450 nm excitation. The photoluminescence quantum yield (PLQY) was measured to be 49.7%, and the emission intensity at 423 K maintains 80.6% of that at 298 K. In addition, a fabricated NIR pc-LED device was used to evaluate the practical applications, which exhibits a high output power of 21.4 mW under a driving current of 100 mA. Using this light source, the applications in night vision and information hiding were demonstrated. These results indicate the feasibility of NaAlP2O7:Cr3+ as a candidate NIR material for spectroscopy applications.