Cr^3+单掺杂及Eu^3+/Cr^3+共掺杂GdAlO3近红外长余辉发光纳米粒子的制备、微结构及光学特性  

Preparation,Microstructure and Optical Properties of Cr^3+ Single-Doped and Eu^ 3+/Cr^3+ Co-Doped GdAlO3 Near Infrared Long Persistent Luminescent Nanoparticles

作　　者：战盈霏 刘春光[1] 王明炜 杨健[1] 祝汉成[1] 严端廷[1] 徐长山[1] 刘玉学[1] ZHAN Ying-fei;LIU Chun-guang;WANG Ming-wei;YANG Jian;ZHU Han-cheng;YAN Duan-ting;XU Chang-shan;LIU Yu-xue(School of Physics,Northeast Normal University,Changchun 130024,China)

机构地区：[1]东北师范大学物理学院,吉林长春130024

出　　处：《光谱学与光谱分析》2021年第1期80-87,共8页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金面上项目(11874103,12074062)资助。

摘　　要：同时可作为磁共振成像造影剂与近红外余辉光学成像光学探针双功能的纳米粒子,在生物医学领域具有重要的应用价值。采用自蔓延燃烧法制备了不同掺杂浓度的GdAlO 3∶x%Cr^3+及GdAlO 3∶1%Cr^3+,y%Eu^3+近红外长余辉发光纳米粒子。并采用X射线衍射、扫描电子显微镜、激发和发射光谱及发光动力学分析等技术手段,较系统地研究了其微结构及光学特性。实验结果表明,Cr^3+取代了GdAlO 3中的Al^3+的格位,单掺样品的平均粒子尺寸约为202 nm。GdAlO 3∶x%Cr^3+样品的激发谱显示,激发峰来源于Cr^3+和Gd^3+的跃迁;在583 nm的激发下,在650~750 nm近红外范围内,出现四个近红外光发射峰。其中,725 nm处的发射峰归属为禁戒跃迁2 E到4 A 2的零声子线,700和750 nm处的发射峰则为声子边带的发射。在0.2%~2.0%的掺杂浓度范围内,随着Cr^3+掺杂浓度的增加,这些发射峰的强度先增强后减弱,最优浓度为1%。而位于735 nm处的发射峰强度随Cr^3+浓度增大而增大,其归属于Cr^3+-Cr^3+对的发光。同时,单掺样品可观察到位于725 nm的长余辉发光,其中GdAlO 3∶1%Cr^3+纳米粒子的余辉时间最长,并超过30 s。在上述Cr^3+最优浓度(1%)基础上,通过Eu^3+取代GdAlO 3基质中Gd^3+的格位,实现了Eu^3+/Cr^3+共掺杂。实验发现,在266 nm激发下,在红光区域范围内可观察到以位于614 nm处的发射为主的一系列发射峰。尤其,由于存在Eu^3+到Cr^3+的能量传递,在近红外区出现了位于725 nm处Cr^3+的近红外发射峰。当Eu^3+浓度为13%时,与Cr^3+单掺杂样品相比,其样品的平均粒子尺寸虽然减小到167 nm,但在275 nm紫外光照射5 mi n停止后,发现共掺样品在位于725 nm处Cr^3+的余辉发光强度明显增强。通过比较分析单掺和共掺样品的吸收和发射光谱及发光动力学的结果,验证了由于Eu^3+到Cr^3+的持续能量传递可引起较显著地近红外余辉发光增强的结论。同时,该研究�It is important to prepare new nanoparticles that can be simultaneously used as contrast agents for magnetic resonance imaging and optical probes for near-infrared afterglow optical imaging in the biomedical field.In this paper,single-phase GdAlO3∶x%Cr^3+ and GdAlO3∶1%Cr^3+ ,y%Eu^3+ near-infrared persistent luminescent nanoparticles with different doping concentrations wereprepared by a self-propagating combustion method.Their microstructure and optical properties were studied by means of X-ray diffraction,scanning electron microscopy,excitation and emission spectra and luminescent kinetics analysis.It is found that,for Cr^3+ single doped samples,Cr^3+ ions replace the Al^3+ sites and the average particle size is~202 nm.From excitation spectra of GdAlO3∶x%Cr^3+ samples,it can be found that,the excitation peaks are attributed to transitions of Cr^3+ and Gd^3+ ions.Meanwhile,four emission peaks appear in the near-infrared range of 650~750 nm upon 583 nm excitation.Among them,the emission peak at 725 nm belongs to the zero phonon line(PZL)and those peaks at 700 and 750 nm can be attributed to the emissions from phonon sidebands(PS)of the 2E→4A2 forbidden transitions,respectively.In the doping concentration range of 0.2%~2.0%,the intensities of these emission peaks show an initial increase and a subsequent decrease with the increase of Cr^3+ doping concentration.When the doping concentration reaches 1%,the strongest intensity can be obtained.However,the intensity of the emission peak at 735 nm increases with the increase of Cr^3+ concentration,which is attributed to the emission from Cr^3+-Cr^3+ pairs.It is found that long afterglow luminescence at 725 nm can be observed for Cr^3+ single-doped nanoparticles.Among them,the afterglow time of GdAlO3∶1%Cr^3+ nanoparticles is the longest and exceeds 30 s.On the basis of the above optimal Cr^3+ concentration(1%),single-phase Eu^3+ Cr^3+ co-doped GdAlO3 nanoparticles were prepared by the replacement of Gd^3+ by Eu^3+ .It is found that several emission peaks domina

关 键 词：光致发光 CR^3+ EU^3+ 能量传递 余辉 荧光粉 

分 类 号：O469[理学—凝聚态物理]