高效稳定的Cr^(3+)离子激活石榴石型宽带近红外荧光粉的发光特性及应用研究

Highly Efficient and Thermally Stable Cr^(3+)-activated Garnet Phosphors for Application in Broadband NIR pc-LEDs

近红外荧光粉转换型发光二极管(NIR pc-LEDs)作为一种紧凑型光源,在近红外光谱技术领域具有广泛的应用前景。然而,开发高效稳定的近红外荧光粉一直面临巨大挑战。本研究报道了一种高效且热稳定优异的Cr^(3+)离子激活Gd_(3)Ga_(5)O_(12)(GGG∶Cr)石榴石近红外荧光粉。在450 nm蓝光激发下,其近红外发射覆盖620~1100 nm范围,最高峰位于740 nm,半高宽为97 nm,内量子效率达54.6%。同时,该荧光粉表现出优异的热稳定性,即在425 K温度时,其近红外发射光谱积分强度为室温的106%(106%@425 K),呈负热猝灭特性。此外,通过Nd^(3+)-Yb^(3+)稀土离子共掺策略,成功实现了材料近红外发射谱带的有效拓宽和热稳定性增强(115%@425 K)。最后,将目标材料与蓝光芯片结合,封装成近红外LED器件,在320 mA电流驱动下,近红外最大输出功率可达55.5 mW,光电转换效率约为6%。以上结果表明,GGG∶Cr,Nd,Yb石榴石荧光粉是一种潜在的高功率近红外LED光源用近红外发光材料。

Broadband near-infrared(NIR)light sources based on NIR phosphor-converted light-emitting diodes(NIR pc-LEDs)are desirable for NIR spectroscopy applications,while desiring thermally stable NIR phosphors has posed a great challenge.Herein,we report a comprehensive study into the synthesis,structural,and photoluminescence properties of Cr^(3+)-activated Gd_(3)Ga_(5)O_(12) garnet phosphors with high efficiency and superior thermal stability.Upon 450 nm excitation,it produces a broadband NIR emission in the 620-1100 nm range with a maximum at 740 nm and a FWHM of 97 nm.Remarkably,the Gd_(3)Ga_(5)O_(12)∶0.12Cr^(3+)phosphor exhibits high internal quantum efficiency of 54.6% and outstanding thermal stability(106%@425 K).Furthermore,spectral broadening and thermal stability enhancement are achieved by the codoping of Nd^(3+)/Yb^(3+)via efficient energy migration between Cr^(3+)and Nd^(3+)/Yb^(3+)ions.Lastly,an NIR pc-LED device fabricated using as-prepared phosphors yields a high NIR output power of 55.5 mW under 320 mA input current,demonstrating their potential application in high-power NIR pc-LEDs.