Developing a Near-Infrared Garnet Phosphor with Near-Unity Internal Quantum Efficiency and Wide-Range Spectral...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are crucial for portable smart devices.
• Developing NIR phosphors with high efficiency, thermal stability, and tunable spectra is challenging.

Purpose of the Study:

• Design and synthesize novel garnet-type phosphors for NIR pc-LED applications.
• Evaluate their performance, including efficiency, thermal stability, and spectral tunability.
• Demonstrate their potential in multifunctional spectroscopy.

Main Methods:

• Garnet-type Ca2GdMA MB Ge3O12:Cr3+ phosphors (MA = Zn, Mg; MB = Sc, In) were synthesized.
• Photoluminescence properties, internal quantum efficiency (IQE), and thermal stability were characterized.
• Spectral tuning was achieved by adjusting the [Na+-Gd3+] substitution ratio.

Main Results:

• Ca2GdZnScGe3O12:Cr3+ exhibited broadband emission centered at 795 nm with 97% IQE under 465 nm excitation.
• High thermal stability was observed, retaining 83.4% emission intensity at 423 K.
• Tunable emission from 795 to 870 nm was achieved, with IQE >90% up to 830 nm.

Conclusions:

• The synthesized Cr3+-doped garnet phosphors demonstrate superior performance for NIR pc-LEDs.
• These materials offer excellent efficiency, thermal stability, and spectral tunability.
• Potential applications in nondestructive testing, information encryption, and organic matter analysis were confirmed.