Zn^(2+)掺杂MgGa_(2)O_(4):Ni^(2+)近红外二区发光材料制备、表征及其成像应用研究

Preparation and Characterization of Zn^(2+)-doped MgGa2O4:Ni^(2+)NIR-ⅡPhosphors and Their Application in Imaging

通过水热法结合后期真空热处理的方法制备了具有反尖晶石结构的Zn_(x)Mg_(0.993-x)Ga_(2)O_(4):0.7%Ni^(2+)(x=0~0.5)(ZMGO:Ni^(2+))近红外二区(NIR-Ⅱ:1000~1700 nm)荧光粉。随着Zn^(2+)掺杂量的增加,ZMGO:Ni^(2+)粉体样品的粒子尺寸逐渐变大。在635 nm激光激发下,可观测到粉体样品位于~1279 nm处的宽带发射峰,其可被归属为Ni^(2+)的特征发射。此外,Zn^(2+)掺杂使样品荧光猝灭的热激活能由244 meV减小到224 meV。采用发光强度最强的ZMGO:Ni^(2+)粉体样品与620 nm红光LED芯片封装成NIR-Ⅱ荧光粉转换LED(NIR-Ⅱpc-LED),并基于NIR-Ⅱ光穿透能力强和不产生生物组织自荧光的特性,以NIR-Ⅱpc-LED为光源,分别研究了其在有遮挡情况的夜视成像和生物组织成像上的应用。

Herein,a series of Zn_(x)Mg_(0.993-x)Ga_(2)O_(4):0.7%Ni^(2+)(x=0-0.5)(ZMGO:Ni^(2+))phosphors with inverse spinel structure were successfully prepared through a hydrothermal method followed by a vacuum heat treatment,emitting within the 2nd near-infrared transmittance window(NIR-Ⅱ:1000-1700 nm).The particle size of ZMGO:Ni^(2+)phosphors exhibited a gradual increase with increasing Zn^(2+)doping content.Upon excitation by a 635 nm laser,ZMGO:Ni^(2+)phosphors exhibited a broad emission band centered at approximately 1279 nm,which can be attributed to the characteristic emission of Ni^(2+).Their thermal activation energy is decreased from 244 meV to 224 meV after Zn^(2+)doping.A NIR-Ⅱphosphor-converted light-emitting diode(NIR-Ⅱpc-LED)was fabricated by employing ZMGO:Ni^(2+)phosphors with the strongest luminescence intensity,in conjunction with a 620 nm red LED chip.Based on high penetration ability,minimal scattering property and auto-fluorescence-free background of NIR-Ⅱlight,night vision imaging with occlusion and tissue imaging were performed using the NIR-Ⅱpc-LED,respectively.