Au@SiO_2/LaF_3∶Ce,Tb复合结构的发光共振能量转移

Abstract

发光共振能量转移(LRET)与给体-受体间的距离密切相关,可体现分子间距离的变化,在生命科学领域有着重要的应用.本文设计并合成了Au@SiO2/LaF3∶Ce,Tb复合纳米结构,研究了LaF3∶Ce,Tb(给体)与Au纳米颗粒(受体)间的LRET行为.通过调控SiO2层厚度,可以改变给体-受体之间的距离.当SiO2层厚度增加到42 nm时,仍能观察到明显的LRET现象.这一距离远超过通常荧光共振能量转移的有效范围,表明由长发光寿命的稀土发光纳米材料与金纳米颗粒形成的给体-受体对可在更大的距离上实现能量转移.

Au@SiO2/LaF3:Ce, Tb nanostructures were synthesized simply by the coprecipitation of LaF3: Ce, Tb in the presence of Au@SiO2 nanoparticles. The as-obtained nanostructures were used as a model system to investigate the luminescence resonance energy transfer(LRET) process, where Tb3+, Au, and SiO2 served as long-lifetime donor, quenching acceptor, and distance spacer, respectively. The LRET efficiency decreased with the increase of the thickness of silica shell. Importantly, the LRET process could still be observed even when the thickness of silica shell increased up to 42 nm. This long-distance LRET phenomenon can be attributed to the long lifetime of Tb3+ and the "point-to-surface" transfer model modified for Au nanoparticle acceptor. This result indicates that the analogous systems could be employed to study the LRET processes that take place over larger distances(>10 nm).