Efficient Broadband Near-Infrared CaMgGe₂O₆:Cr³⁺ Phosphor for pc-LED

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are essential to integrate near-infrared spectrometers into mobile devices for the rapid and noninvasive detection of biological components. However, efficient broadband NIR phosphors with a peak emission wavelength longer than 800 nm are deficient. In this study, CaMgGe₂O₆:Cr³⁺ phosphor was prepared by a high-temperature solid-state reaction. The phosphor doped with 0.02Cr³⁺ showed an emission band at 845 nm with a broad bandwidth of 160 nm and a high quantum yield of 84% under 450 nm excitation. The broadband NIR pc-LED was fabricated using CaMgGe₂O₆:0.02Cr³⁺ phosphor based on a blue light-emitting diode (LED) chip. A photoelectric efficiency of 27.2% @ 10 mA and an NIR output power of 57.98 mW @ 100 mA were achieved, which are the highest values reported yet for broadband NIR pc-LEDs with a peak wavelength longer than 800 nm. Using the fabricated NIR pc-LED as the light source, the characteristic absorption spectra of some substances were obtained. All of the results indicated that the CaMgGe₂O₆:Cr³⁺ phosphor has considerable potential in near-infrared spectroscopic applications.