Controlled synthesis and optical spectroscopy of lanthanide-doped KLaF4 nanocrystals
Controlled synthesis and optical spectroscopy of lanthanide-doped KLaF4 nanocrystals
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镧系元素掺杂 KLaF4 纳米晶的控制合成与光谱
DOI：
10.1039/c2nr30794d
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发表时间：
2012-01-01
期刊：
影响因子：
6.7
通讯作者：
Chen, Xueyuan
中科院分区：
文献类型：
--
作者：
Liu, Rui;Tu, Datao;Chen, Xueyuan
KLaF4作为三价稀土(Ln(3+))离子制备上转换(UC)或下转换(DC)荧光粉的良好基质，目前还鲜有报道。本文采用简单的热分解法制备单分散(约10 nm)立方相Ln(3+)掺杂KLaF4纳米晶(NCS)。在980 nm激发下，研究了KLaF4：Ln(3+)/Yb3+(Ln Tm，Ho，Er)纳米管的UC发光特性。特别是，包覆惰性KLaF4壳层后，KLaF4：Er~(3+)/Yb~(3+)纳米管的绿光和红光的发光强度提高了近35倍，而相应的S-4(3/2)和F-4(9/2)的荧光寿命从只有核的NCS的42和68ms显著延长到核/壳NCS的87ms和136ms。此外，Ce~(3+)/Tb~(3+)和Eu~(3+)掺杂的KLaF_4纳米管也获得了很强的直流发光，其绝对量子产率分别为39.8%(Tb~(3+))和17.3%(Eu~(3+))。测得D-5(0)(Eu3+)和D-5(4)(Tb3+)的发光寿命分别为4.2ms和4.7ms。水溶性Ln(3+)掺杂KLaF4纳米碳管具有优良的单分散性、较长的发光寿命和较高的UC/DC效率，作为发光纳米生物标记具有广泛的应用前景。
KLaF4, as a good host matrix for trivalent lanthanide (Ln(3+)) ions to fabricate upconversion (UC) or downconversion (DC) phosphors, has been rarely reported. Herein, monodisperse (similar to 10 nm) cubic-phase Ln(3+)-doped KLaF4 nanocrystals (NCs) were synthesized via a facile thermal decomposition method. Upon excitation at 980 nm, UC luminescence properties of KLaF4:Ln(3+)/Yb3+ (Ln Tm, Ho, Er) NCs were comprehensively surveyed. Particularly, after coating an inert KLaF4 shell, the green and red UC luminescence intensity of KLaF4: Er3+/Yb3+ NCs was enhanced similar to 35 times, and the corresponding UC lifetimes of S-4(3/2) and F-4(9/2) levels of Er3+ were observed significantly prolonged from 42 and 68 ms in core-only NCs to 87 and 136 ms in core/shell counterparts. Furthermore, intense DC luminescence was also achieved in Ce3+/Tb3+ and Eu3+ doped KLaF4 NCs, with absolute quantum yields of 39.8% (Tb3+) and 17.3% (Eu3+). The luminescence lifetimes of D-5(0) (Eu3+) and D-5(4) (Tb3+) were determined to be 4.2 and 4.7 ms, respectively. Water-soluble Ln(3+)-doped KLaF4 NCs featuring excellent monodispersion, long luminescence lifetime, and high UC/DC efficiency may have versatile and promising applications as luminescent nano-biolabels.