光子上转换
兴奋剂
近红外光谱
发光
吸收(声学)
光谱学
红外线的
离子
作者
Guanying Chen,Tymish Y. Ohulchanskyy,Sha Liu,Wing Cheung Law,Fang Wu,Mark T. Swihart,Hans Ågren,Paras N. Prasad
出处
期刊:ACS Nano
[American Chemical Society]
日期:2012-03-14
卷期号:6 (4): 2969-2977
被引量:340
摘要
We have synthesized core/shell NaGdF4:Nd3+/NaGdF4 nanocrystals with an average size of 15 nm and exceptionally high photoluminescence (PL) quantum yield. When excited at 740 nm, the nanocrystals manifest spectrally distinguished, near-infrared to near-infrared (NIR-to-NIR) downconversion PL peaked at ∼900, ∼1050, and ∼1300 nm. The absolute quantum yield of NIR-to-NIR PL reached 40% for core–shell nanoparticles dispersed in hexane. Time-resolved PL measurements revealed that this high quantum yield was achieved through suppression of nonradiative recombination originating from surface states and cross relaxations between dopants. NaGdF4:Nd3+/NaGdF4 nanocrystals, synthesized in organic media, were further converted to be water-dispersible by eliminating the capping ligand of oleic acid. NIR-to-NIR PL bioimaging was demonstrated both in vitro and in vivo through visualization of the NIR-to-NIR PL at ∼900 nm under incoherent lamp light excitation. The fact that both excitation and the PL of these nanocrystals...
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