Achieving Ultra‐Broadband Near‐Infrared Emission in Cr3+‐Activated Cs2NaScCl6 Perovskite for Efficient Phosphor‐Converted Light‐Emitting Diodes

Ultra‐broadband near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) have great application prospects in research and industrial fields. However, simultaneously achieving highly efficient and ultra‐broad NIR emission in phosphor material remains a challenge. Herein, an ultra‐broadband NIR emission in the range of 800–1200 nm with ultra‐high emission efficiency of up to 64.2% is first achieved by substituting the Sc3+ site in Cs2NaScCl6 perovskite single‐crystal with a Cr3+ ion. By combining the experimental results with first‐principles calculations, an efficient charge transfer sensitization process from host to Cr3+ is found to be the fundamental reason for the ultra‐high NIR emission efficiency. Benefiting from the excellent efficiency and superior chemical resistance to heat and UV radiation, an ultra‐broadband NIR pc‐LED made of this phosphor demonstrates great potential in biomedical imaging, nondestructive testing, and night‐vision devices.