Modifying the Spectral Weights of Vibronic Transitions via Strong Coupling to Surface Plasmons
Modifying the Spectral Weights of Vibronic Transitions via Strong Coupling to Surface Plasmons
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DOI：
10.1021/acsphotonics.9b01357
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发表时间：
2020-01-01
期刊：
影响因子：
7
通讯作者：
Menon, Vinod M.
中科院分区：
文献类型：
--
作者：
Deshmukh, Rahul;Marques, Paulo;Menon, Vinod M.
强的光-物质耦合导致了混合的半轻半物质激发态的形成，并改变了能级。有机分子体系中激子与光子的强耦合由于其潜在的光物理性质和控制化学反应的前景而受到人们的广泛关注。影响化学反应的一种方法是在分子的振动流形内控制分子的激发态。在这里，我们展示了通过与表面等离子体激元的强耦合来修饰典型的有机分子--二铟杂环戊二烯(DIP)中振动跃迁和准分子发射的光谱重量。垂直排列的DIP分子生长在具有3 nm厚的氧化铝隔离层的超光滑的银膜上。通过角度分辨反射率的测量，我们证明了银的表面等离子体激元模式与DIP中的振动跃迁之间的强耦合。依赖温度的光致发光测量表明，当分子处于强耦合区域时，发射峰的光谱重量发生了移动-这种变化归因于由于Franck-Condon因子的修改和向低位准分子态的有效能量转移而对发射态振子强度的极化子控制。这项工作展示了通过强烈的光-物质相互作用来改变材料性质的可能性。
Strong light-matter coupling results in the formation of hybrid half-light half-matter excitations with modified energy levels. The strong coupling of excitons with photons in organic molecular systems has received much attention recently owing to the potential for engineering their photophysical properties and even the prospects for controlling chemical reactions. One means to affect chemical reactions is to control the molecular excited states within their vibronic manifolds. Here we demonstrate the modification of the spectral weight of the vibronic transitions and excimer emission in an archetype organic molecule, diindenoperylene (DIP), by strong coupling to surface-plasmon polaritons. The vertically aligned DIP molecule is grown on an ultrasmooth film of Ag with a 3 nm thick alumina spacer. Through angle-resolved reflectivity measurements we demonstrate the strong coupling between the surface-plasmon mode of the Ag and the vibronic transitions in DIP. Temperature-dependent photoluminescence measurements show the shift in the spectral weight of the emission peaks when the molecules are in the strong coupling regime-changes that are attributed to the polaritonic control of the oscillator strengths of emissive states owing to modification in the Franck-Condon factor and efficient energy transfer to lower-lying excimer states. This work demonstrates the potential to modify the material properties through a strong light-matter interaction.