Developing Broadband Cr3+-Substituted Phosphor-Converted Near-Infrared Light Sources

Near-infrared (NIR) spectroscopy is a rapidly growing research area due to its noninvasive, inexpensive, and rapid analysis capabilities spanning various applications. The key technology behind the growth of this field involves phosphor-converted NIR light-emitting diodes (pc-NIR LEDs) due to their energy efficiency, long operating lifetimes, and chemical and physical stability. Numerous studies have reported new Cr3+-substituted phosphors that can more effectively convert blue LED emission to NIR radiation with a broad full-width-at-half-maximum (fwhm) that covers a significant portion of the interatomic vibrational spectrum. However, there is still much to learn about these materials' structure–property relationships. In this Spotlight on Applications, we discuss current research progress in designing broadband Cr3+ phosphors as sources of NIR light, specifically emphasizing our research. We examine results from our work and others that have been used to create an efficient broadband emission in the NIR range. The discussion also emphasizes various techniques to analyze and improve temperature-dependent photoluminescence. Finally, we highlight the potential applications of Cr3+-based pc-NIR LEDs in fields such as night vision, bioimaging, and food freshness and analysis. This Spotlight on Applications aims to provide an overview of the progress of pc-NIR LEDs based on Cr3+ by emphasizing the challenges associated with its advancement while offering a few suggestions for ventures in this field.