Up-conversion Luminescence Enhanced by the Plasmonic Lattice Resonating at the Transparent Window of Water
Up-conversion Luminescence Enhanced by the Plasmonic Lattice Resonating at the Transparent Window of Water
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DOI：
10.1021/acsaem.0c01826
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发表时间：
2021-03-30
影响因子：
6.4
通讯作者：
Tanaka, Katsuhisa
中科院分区：
文献类型：
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作者：
Gao, Yuan;Murai, Shunsuke;Tanaka, Katsuhisa
以Yb3+为敏化剂的稀土掺杂上转换器在λ = 980 nm激发下具有较高的内转换效率。然而，对于上转换器的太阳能电池应用，存在λ = 980 nm处的太阳光被大气中的水分子吸收的问题。虽然Nd-3（+）共掺杂允许在λ = 800 nm附近的水透明窗口处进行上转换，但由于4f-4f跃迁的禁性，Nd3+的吸收系数仍然很小。在15 W/cm(2) λ = 808 nm激发下，我们通过将Nd3+敏化的上转换纳米粒子与铝纳米柱的周期晶格耦合，实现了与平板玻璃（在平板铝膜上）相同层的上转换增强44倍（8.9倍）。设计纳米柱的尺寸和晶格周期，实现λ = 800 nm附近的晶格共振，促进Nd-3(+) I-4(9/2) -> F-4（5/2）跃迁至产率放大的上转换。数值模拟表明，上转换增强是由近场增强和晶格模式激发引起的，其中面内光衍射促进了每个纳米圆柱体中局部表面等离子体的辐射耦合。这是Al纳米结构在λ = 808 nm透明水窗处的上转换增强的首次演示，将有助于有效利用太阳辐照。
Rare-earth-doped up-converters with Yb3+ as a sensitizer show a high internal conversion efficiency under the excitation at wavelength lambda = 980 nm. For the solar cell applications of up-converters, however, there is a problem that the solar light at lambda = 980 nm is absorbed by the water molecule in the atmosphere. While Nd-3(+) co-doping allows the up-conversion at the transparent window of water around lambda = 800 nm, the absorption coefficient of Nd3+ is still small due to the forbidden nature of 4f-4f transition. Here, we achieve amplified up-conversion enhancement of 44-fold (8.9-fold) compared to the same layer on the flat glass (on the flat aluminum film) by coupling the Nd3+-sensitized up-conversion nanoparticles with the periodic lattice of aluminum nanocylinders under 15 W/cm(2) of lambda = 808 nm excitation. The size of nanocylinders and the period of the lattice are designed to realize the lattice resonance around lambda = 800 nm, facilitating the Nd-3(+) I-4(9/2) -> F-4(5/2) transition to yield amplified up-conversion. Numerical simulation indicates that the up-conversion enhancement is induced by an intensified near field accompanied with the excitation of lattice modes, where the in-plane light diffraction facilitates the radiative coupling of localized surface plasmons in each nanocylinder. This is the first demonstration of up-conversion enhancement at the transparent water window at lambda = 808 nm by the combination of Al nanostructure and would contribute to the efficient use of solar irradiation.