Creating an efficient and tunable near-infrared emission by using [Mg2+-Sn4+] chemical unit co-substitution in Ga2O3:Cr3+ phosphor

NIR phosphor-converted light-emitting diode (NIR pc-LED) has attracted many attentions for its promising applications in biomedical imaging, night vision, spectroscopy, and many other fields, while the discovery of broadband NIR phosphors with high external quantum efficiency (EQE) remains a challenge. Herein, a series of efficient and tunable broadband NIR-emitting Ga1.97-2xMgxSnxO3:0.03Cr3+ phosphors were synthesized via [Mg2+-Sn4+] substituting [Ga3+-Ga3+] in Ga2O3:Cr3+ system. As increase of substituting ratio x, a significant red-shift in the emission spectra from 726 to 793 nm with a full width at half maximum (FWHM) extended from 121 to 167 nm can be observed. All the samples have an EQE above 40% under 450 nm excitation; and the excitation peak in the blue light region remains unchanged, enabling these materials to be efficiently excited by blue LEDs. Finally, a NIR pc-LED device was fabricated by integrating the optimized Ga1.77Mg0·1Sn0·1O3:0.03Cr3+ phosphor on a blue LED chip, which exhibits a high NIR output power of 33.41 mW with a photoelectric conversion efficiency of 12.01% under a drive current of 100 mA. These results indicate that the obtained NIR phosphors may have potential in NIR pc-LEDs applications.