Ce^(3+),Cr^(3+)co-doped garnet phosphors with yellow and near-infrared emission for white and near-IR dual-mode pc-LEDs

黄光与近红外发射的Ce^(3+),Cr^(3+)共掺杂石榴石荧光粉用于白光与近红外双模式pc-LEDs

Cr^(3+)-activated phosphors with adjustable near-infrared(NIR)emission have attracted considerable attention due to their diverse applications across various fields.While modifying the emission wavelength of Cr^(3+)can be achieved by adjusting its coordination environment,the parity-forbidden d-d transition presents a challenge by limiting absorption and resulting in a low external quantum efficiency(EQE)in Cr^(3+)-doped phosphors.Moreover,longer emission wavelengths often coincide with reduced thermal stability.To address these issues,energy transfer from a sensitizer to Cr^(3+)has been proposed as a strategy to enhance both EQE and thermal stability of NIR emission.The selection of an appropriate host structure is crucial.In this study,a garnet structure,Ca_(2)LuMgScSi_(3)O_(12),was identified as a promising candidate for achieving efficient broadband NIR emission under blue light excitation.Specifically,Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+)exhibited a yellow emission with exceptional internal quantum efficiency and EQE of up to 94.6%and 64.8%,respectively.By leveraging efficient energy transfer from Ce^(3+)to Cr^(3+),the Ca_(2)LuMgScSi_(3)-O_(12):Ce^(3+),Cr^(3+)phosphors exhibited tunable yellow to NIR emission.Notable,the highest EQE recorded for Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+),Cr^(3+)was 56.9%,significantly surpassing that of the Cr^(3+)single-doped counterpart.Furthermore,the co-doped phosphor demonstrated thermal stability comparable to that of Ce^(3+)single-doped phosphor.Of particular significance,the developed prototype pc-LED emitted a combination of broadband white and NIR light,demonstrating potential applications in solar-like lighting,food analysis,and biomedical imaging.

具有可调近红外(NIR)发射的Cr^(3+)激活荧光粉因其在多个领域的应用而备受关注.通过改变Cr^(3+)的配位环境可改变其发射波长,但其宇称禁阻的d-d跃迁阻碍了吸收,降低了外量子效率(EQE).此外,较长的发射波长通常伴随着较差的热稳定性.为了解决这些问题,本文提出了通过敏化剂到Cr^(3+)的能量传递提高近红外发射的EQE和热稳定性的策略.其中,选择合适的基质结构至关重要.本文以石榴石结构Ca_(2)LuMgScSi_(3)O_(12)作为候选,来实现在蓝光激发下的高效宽带NIR发射.具体来说,Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+)发射黄光,其内量子效率(IQE)和EQE分别高达94.6%和64.8%.利用从Ce^(3+)到Cr^(3+)的高效能量传递,Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+),Cr^(3+)荧光粉具有从黄色到NIR的可调发光.值得注意的是,Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+),Cr^(3+)的最高EQE为56.9%,远高于Cr^(3+)单掺杂样品的EQE值.共掺杂荧光粉具有与Ce^(3+)单掺杂荧光粉相当的热稳定性.所制备的原型pc-LED可同时发射宽带白光和近红外光,展示了其在类太阳光、食品分析和生物医学成像等方面的潜在应用.