Athanasiou Stavros, Martin Olivier J F
Nanophotonics and Metrology Laboratory (NAM), Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne 1015, Switzerland.
J Phys Chem C Nanomater Interfaces. 2024 Oct 22;128(43):18574-18581. doi: 10.1021/acs.jpcc.4c05322. eCollection 2024 Oct 31.
Noble metals such as gold and silver have been used extensively for a range of plasmonic applications, including enhancing the fluorescence rate of a dye molecule, as evidenced by numerous experiments over the past two decades. Recently, a variety of doped semiconductors have been proposed as alternative plasmonic materials, exhibiting plasmonic resonances from ultraviolet to far-infrared. In this work, we investigate the suitability of these alternative materials for enhancing the fluorescence of a molecule. Considering nanosized spheres, we study their response under plane wave illumination and the resulting enhancement factors when coupled to a quantum emitter. Comparisons with standard plasmonic metals reveal that semiconductor materials lead to a significantly reduced, and often strongly quenched, emission of light caused by their dominant absorption, which hinders fluorescence enhancement. However, we show that enhancement may be obtained when considering poor emitting dyes and high refractive index environments. Our findings demonstrate that these alternative materials result in weaker fluorescence enhancement compared to their plasmonic counterparts. Nonetheless, there are means to compensate for this, and a reasonable enhancement can be achieved for dyes in the infrared spectrum.
诸如金和银之类的贵金属已被广泛用于一系列等离子体应用中，包括提高染料分子的荧光速率，过去二十年的大量实验证明了这一点。最近，人们提出了各种掺杂半导体作为替代等离子体材料，它们在从紫外到远红外的范围内表现出等离子体共振。在这项工作中，我们研究了这些替代材料增强分子荧光的适用性。考虑到纳米球，我们研究了它们在平面波照射下的响应以及与量子发射器耦合时产生的增强因子。与标准等离子体金属的比较表明，半导体材料由于其主要吸收导致光发射显著减少，并且常常强烈猝灭，这阻碍了荧光增强。然而，我们表明，当考虑发射较弱的染料和高折射率环境时，可以获得增强效果。我们的研究结果表明，与等离子体对应物相比，这些替代材料导致的荧光增强较弱。尽管如此，有办法弥补这一点，并且可以实现红外光谱中染料的合理增强。
