Proença Manuela, Rodrigues Marco Sampaio, Borges Joel, Vaz Filipe
Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
Anal Chem. 2020 Mar 17;92(6):4349-4356. doi: 10.1021/acs.analchem.9b05153. Epub 2020 Feb 26.
Gas sensing based on bulk refractive index (RI) changes, has been a challenging task for localized surface plasmon resonance (LSPR) spectroscopy, presenting only a limited number of reports in this field. In this work, it is demonstrated that a plasmonic thin film composed of Au nanoparticles embedded in a CuO matrix can be used to detect small changes (as low as 6 × 10 RIU) in bulk RI of gases at room temperature, using a high-resolution LSPR spectroscopy system. To optimize the film's surface, a simple Ar plasma treatment revealed to be enough to remove the top layers of the film and to partially expose the embedded nanoparticles, and thus enhance the film's gas sensing capabilities. The treated sample exhibits high sensitivity to inert gases (Ar, N), presenting a refractive index sensitivity (RIS) to bulk RI changes of 425 nm/RIU. Furthermore, a 2-fold signal increase is observed for O, showing that the film is clearly more sensitive to this gas due to its oxidizing nature. The results showed that the Au:CuO thin film system is a RI sensitive platform able to detect inert gases, which can be more sensitive to detect noninert gases as O or even other reactive species.
基于体折射率（RI）变化的气体传感，对于局域表面等离子体共振（LSPR）光谱来说一直是一项具有挑战性的任务，该领域的相关报道数量有限。在这项工作中，结果表明，由嵌入CuO基体中的金纳米颗粒组成的等离子体薄膜，可用于在室温下利用高分辨率LSPR光谱系统检测气体体RI的微小变化（低至6×10 RIU）。为了优化薄膜表面，一种简单的氩等离子体处理被证明足以去除薄膜的顶层并部分暴露嵌入的纳米颗粒，从而增强薄膜的气敏能力。经过处理的样品对惰性气体（Ar、N）表现出高灵敏度，对体RI变化的折射率灵敏度（RIS）为425 nm/RIU。此外，对于O观察到信号增强了2倍，这表明由于其氧化性质，该薄膜对这种气体明显更敏感。结果表明，Au:CuO薄膜系统是一个对RI敏感的平台，能够检测惰性气体，对检测非惰性气体如O甚至其他反应性物种可能更敏感。
