Ca_(2)TbHf_(2)Al_(3)O_(12)∶Ce^(3+),Cr^(3+)石榴石荧光材料的宽带近红外发射与能量传递

Broadband Near Infrared Emission and Energy Transfer of Ca_(2)TbHf_(2)Al_(3)O_(12)∶Ce^(3+),Cr^(3+)Garnet Phosphor

近红外荧光转换型发光二极管(pc‐LED)在光谱分析、生物成像、夜视照明等领域有重要应用价值,得到了人们的广泛关注。本文采用高温固相法制备了一系列Ca_(2)TbHf_(2)Al_(3)O_(12)∶Ce^(3+),xCr^(3+)(CTHAO∶Ce^(3+),xCr^(3+))近红外荧光材料,通过粉末XRD表征结合结构精修技术确定制备的CTHAO∶Ce^(3+),xCr^(3+)为纯相石榴石结构。在该样品中,Tb^(3+)作为基质组成,与掺杂离子Ce^(3+)共同作为Cr^(3+)离子的敏化剂,三者之间存在多种能量传递效应,通过光谱及荧光寿命表征证实存在Ce^(3+)→Tb^(3+)、Ce^(3+)→Cr^(3+)、Tb^(3+)→Cr^(3+)的能量传递过程;重点分析了Tb^(3+)向Cr^(3+)的能量传递机制,以偶极‐四极交互作用为主导,能量传递效率可达79.5%。CTHAO∶Ce^(3+),0.02Cr^(3+)在100℃时的近红外发射强度能保持初始强度的36%,计算得到活化能为0.30 eV。将该样品与410 nm芯片相结合制成器件,在驱动电流为200 mA时,近红外最大输出功率可达7.5 mW,光电转换效率为1.2%。本工作研究了通过多重能量传递提高Cr^(3+)的发光,对于设计和开发Cr^(3+)激发的高效近红外发光材料有一定的指导意义。

Broadband near infrared(NIR)phosphor-converted light-emitting diodes(pc-LEDs)have been widely concerned due to their valuable application in spectral analysis,biological imaging,night vision lighting and other fields.In this work,the novel NIR-emitting Ca_(2)TbHf_(2)Al_(3)O_(12)∶Ce^(3+),xCr^(3+)(CTHAO∶Ce^(3+),xCr^(3+))phosphors were prepared by high temperature solid state method.CTHAO∶Ce^(3+),xCr^(3+)were confirmed to be pure phase with garnet structure by powder XRD and Rietveld refinement technology.Tb^(3+),as matrix component,can sensitize Cr^(3+)ions.Codoping Ce^(3+)leads to multiple energy transfer processes,and the energy transfer fact of Ce^(3+)→Tb^(3+),Ce^(3+)→Cr^(3+),Tb^(3+)→Cr^(3+)was confirmed by the spectra and fluorescence lifetime characterization.The energy transfer mechanism from Tb^(3+)to Cr^(3+)is dominated by dipole-quadrupole interaction,and the energy transfer efficiency can reach 79.5%.The NIR intensity of CTHAO∶Ce^(3+),0.02Cr^(3+)can maintain 36%compared with its initial intensity and the calculated activation energy is 0.30 eV.Combining CTHAO∶Ce^(3+),0.02Cr^(3+)with a 410 nm chip,the NIR output power can reach 7.5 mW and the NIR photoelectric conversion efficiency is 1.2%when the driving current is 200 mA.In this work,the enhancement of Cr^(3+)luminescence through multiple energy transfer processes has certain guiding significance for the design and development of Cr^(3+)excited efficient near infrared luminescence materials.