Abbass A E, Swart H C, Kroon R E
Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa.
Department of Physics, Sudan University of Science and Technology, Khartoum, Sudan.
Luminescence. 2016 Sep;31(6):1182-6. doi: 10.1002/bio.3086. Epub 2016 Jan 14.
Although noble metal nanoparticles (NPs) have attracted some attention for potentially enhancing the luminescence of rare earth ions for phosphor lighting applications, the absorption of energy by NPs can also be beneficial in biological and polymer applications where local heating is desired, e.g. photothermal applications. Strong interaction between incident laser light and NPs occurs only when the laser wavelength matches the NP plasmon resonance. Although lasers with different wavelengths are available and the NP plasmon resonance can be tuned by changing its size and shape or the dielectric medium (host material), in this work, we consider exciting the plasmon resonance of Ag NPs indirectly with a He-Cd UV laser using the down-conversion properties of Tb(3+) ions in ZnO. The formation of Ag NPs was confirmed by X-ray diffraction, transmission electron microscopy and UV-vis diffuse reflectance measurements. Radiative energy transfer from the Tb(3+) ions to the Ag NPs resulted in quenching of the green luminescence of ZnO:Tb and was studied by means of spectral overlap and lifetime measurements. The use of a down-converting phosphor, possibly with other rare earth ions, to indirectly couple a laser to the plasmon resonance wavelength of metal NPs is therefore successfully demonstrated and adds to the flexibility of such systems. Copyright © 2016 John Wiley & Sons, Ltd.
尽管贵金属纳米颗粒（NPs）因在磷光照明应用中可能增强稀土离子的发光而受到一定关注，但在诸如光热应用等需要局部加热的生物和聚合物应用中，NPs对能量的吸收也可能是有益的。仅当激光波长与NP等离子体共振匹配时，入射激光与NPs之间才会发生强烈相互作用。虽然有不同波长的激光可用，并且可以通过改变NP的尺寸和形状或介电介质（主体材料）来调节NP等离子体共振，但在本工作中，我们考虑利用ZnO中Tb(3+)离子的下转换特性，用氦镉紫外激光间接激发Ag NPs的等离子体共振。通过X射线衍射、透射电子显微镜和紫外可见漫反射测量证实了Ag NPs的形成。从Tb(3+)离子到Ag NPs的辐射能量转移导致ZnO:Tb绿色发光猝灭，并通过光谱重叠和寿命测量进行了研究。因此，成功证明了使用下转换荧光粉（可能与其他稀土离子一起）将激光间接耦合到金属NP的等离子体共振波长，这增加了此类系统的灵活性。版权所有© 2016约翰威立父子有限公司。
