Multifunctional Phosphors with Ultra-Broadband Near-Infrared Emission (700 - 1700 nm)

Due to the limitations of currently commercially available electroluminescent LEDs operating in the infrared range such as low output power, low thermal stability, narrow emission bands, and high production cost, new materials are being sought to overcome these drawbacks. Broadband, near-infrared phosphors-converted light-emitting diodes with high efficiency and the ability to achieve high-intensity luminescence spectra in the near-infrared range are being sought for biosensor applications [1], [2]. In recent years, there has been a notable surge of interest in photonic materials containing rare-earth (RE) ions. Ln<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>+ ions are characterized by long excited-state lifetimes, narrow emission and absorption bands, large Stokes shifts, and complex 4f electronic energy level structures. These properties have led to the widespread utilization of RE-based materials in various light-management applications [3]. Glass-ceramics doped with ions of transition metals such as chromium ions Cr<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup>/Cr<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4+</sup>) are characterized by broad near-infrared (NIR) emission bands [4], [5]. Glass-ceramic can be both a carrier for crystals, in terms of an adapter for suspending phosphors, and offers the possibility of crystallizing other compounds, as exemplified by the phosphor-in-glass method (PiG) [6].