An unusually sharp localized surface plasmon resonance (sLSPR) is observed for a monolayer of glass-supported silver nanocubes coated with a thin, 5–20 nm, Al₂O₃ film. The resonance becomes significantly narrower and stronger while losing optical anisotropy and sensitivity to the surroundings with increasing overlayer thickness. Surface-enhanced Raman scattering excitation profiles indicate an additional enhancement to the electric field brought in by the sLSPR. The resonance is thought to originate from a Fano-like constructive interference between the quadrupolar and dipolar LSPR modes in supported silver nanocubes leading to enhanced light extinction. This phenomenon is of significance for plasmon-induced charge-transfer processes in photovoltaics and catalysis.

中文翻译：

---

带有薄介电涂层的负载银纳米晶体中异常锋利的局部表面等离子共振

对于单层玻璃支撑的银纳米立方体，其表面涂覆了5-20 nm的Al ₂ O ₃薄膜，观察到了异常尖锐的局部表面等离子体激元共振（sLSPR）。随着覆盖层厚度的增加，共振会明显变窄和变强，同时失去光学各向异性和对周围环境的敏感性。表面增强的拉曼散射激发轮廓表明sLSPR引入的电场得到了额外的增强。共振被认为源于负载的银纳米立方体中四极和双极LSPR模式之间的Fano类相长干涉，从而增强了光的消光性。这种现象对于光伏中的等离激元诱导的电荷转移过程和催化具有重要意义。