Shao Qiyue, Ding Hao, Yao Leqi, Xu Junfeng, Liang Chao, Jiang Jianqing
School of Materials Science and Engineering, Jiangsu Key Laboratory for Advanced Metallic Materials, Southeast University Nanjing 211189 PR China
Jiangsu Bree Optronics Co., Ltd. Nanjing 211103 PR China.
RSC Adv. 2018 Mar 28;8(22):12035-12042. doi: 10.1039/c8ra01084f. eCollection 2018 Mar 26.
The rapid extension of solid state lighting technologies offers the possibility to develop broadband near-infrared (NIR) phosphor-converted LEDs (pc-LEDs) as novel NIR light sources. In this paper, a new NIR-emitting phosphor ScBO:Cr was synthesized by a high temperature solid state reaction method. Phase structure, spectroscopic properties, luminescent lifetime, quantum yield, emitter concentration influences and thermal quenching behavior of ScBO:Cr, as well as its applications for NIR pc-LEDs, were systematically investigated. ScBO:Cr phosphors exhibit a broad absorption band ranging from 400 to 530 nm, which matches well with the characteristic emission of the blue LED chip. Moreover, Cr ions occupy the Sc sites with relatively low crystal field strength in the ScBO host, and therefore ScBO:Cr phosphors show intense broadband emission peaking at ∼800 nm upon excitation at 460 nm, originating from spin-allowed T → A transition of Cr ions. The optimum Cr concentration was determined to be ∼2 mol% with a quantum yield of ∼65%. A broadband NIR pc-LED prototype device was fabricated by the combination of ScBO:Cr phosphors and a blue LED chip, which showed a maximum NIR light output power of ∼26 mW and a corresponding energy conversion efficiency of ∼7%. The results indicate the great potential of ScBO:Cr phosphors for applications in broadband NIR pc-LEDs.
固态照明技术的迅速发展为开发宽带近红外（NIR）荧光粉转换发光二极管（pc-LED）作为新型近红外光源提供了可能性。本文采用高温固相反应法合成了一种新型近红外发光荧光粉ScBO:Cr。系统研究了ScBO:Cr的相结构、光谱性质、发光寿命、量子产率、发光剂浓度影响和热猝灭行为，以及其在近红外pc-LED中的应用。ScBO:Cr荧光粉呈现出400至530 nm的宽吸收带，与蓝色发光二极管芯片的特征发射很好地匹配。此外，Cr离子在ScBO基质中占据晶体场强度相对较低的Sc位点，因此ScBO:Cr荧光粉在460 nm激发下呈现出在800 nm处峰值的强烈宽带发射，源于Cr离子的自旋允许T→A跃迁。确定最佳Cr浓度为2 mol%，量子产率约为65%。通过将ScBO:Cr荧光粉与蓝色发光二极管芯片结合制备了宽带近红外pc-LED原型器件，其显示出最大近红外光输出功率约为26 mW，相应的能量转换效率约为7%。结果表明ScBO:Cr荧光粉在宽带近红外pc-LED应用中具有巨大潜力。
