Co-Deposition of Gold Nanoparticles and Metalloporphyrin Using the Langmuir Blodgett (LB) Technique for Surface-Enhanced Raman Scattering (SERS)
Co-Deposition of Gold Nanoparticles and Metalloporphyrin Using the Langmuir Blodgett (LB) Technique for Surface-Enhanced Raman Scattering (SERS)
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DOI：
10.1366/14-07625
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发表时间：
2015-04-01
影响因子：
3.5
通讯作者：
Constantino, Carlos J. L.
中科院分区：
文献类型：
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作者：
Camacho, Sabrina A.;Aoki, Pedro H. B.;Constantino, Carlos J. L.
金属纳米粒子融入不同系统时产生的协同效应推动了快速发展的研究领域。此外，有机金属材料是深入研究的中心，具有多种应用，如发光器件、晶体管、太阳能电池和传感器。 Langmuir Blodgett (LB) 技术已被证明适合解决有机器件固有的挑战，因为薄膜特性可以在分子水平上进行调整。在这里，我们报告了一种通过共沉积将金纳米颗粒（AuNP）掺入LB膜中的策略，以实现锌（II）-原卟啉（IX）二甲酯（ZnPPIX-DME）的表面增强拉曼散射（SERS）。在LB共沉积之前，通过表面压力与平均分子的关系研究了亚相中含有AuNPs的ZnPPIX-DME的朗缪尔单层在空气-水界面处的性质。面积 (pi-A) 等温线。 ZnPPIX-DME-FAuNPs pi-A 等温线呈现出向更高分子区域的显着转变，表明 ZnPPIX-DME 分子和 AuNPs 之间存在相互作用。这些相互作用是允许 AuNP 和 ZnPPIX-DME 分子共沉积到固体基底上，从而形成 LB 膜的关键因素。 ZnPPIX-DME 的 SERS 成功实现，确保了 AuNP 的空间分布。由于金属纳米颗粒聚集体中存在强烈的局部电磁场，AuNP 聚集体中发现了更高的增强因子。 SERS 光谱中观察到的主要振动带表明 ZnPPIX-DME 物理吸附到 AuNPs 表面。后者不仅与 pi-A 等温线指出的相互作用一致，而且表明这种相互作用在 LB 膜共沉积时得以保留。
The synergistic effect produced by metallic nanoparticles when incorporated into different systems empowers a research field that is growing rapidly. In addition, organometallic materials are at the center of intensive research with diverse applications such as light-emitting devices, transistors, solar cells, and sensors. The Langmuir Blodgett (LB) technique has proven to be suitable to address challenges inherent to organic devices, since the film properties can be tuned at the molecular level. Here we report a strategy to incorporate gold nanoparticles (AuNPs) into the LB film by co-deposition in order to achieve surface-enhanced Raman scattering (SERS) of the zinc(II)-protoporphyrin (IX) dimethyl ester (ZnPPIX-DME). Prior to the LB co-deposition, the properties of the Langmuir monolayer of ZnPPIX-DME at the air water interface, containing AuNPs in the subphase, are studied through the surface-pressure versus mean molecular. area (pi-A) isotherms. The ZnPPIX-DME-FAuNPs pi-A isotherm presented a significant shift to higher molecular area, suggesting an interaction between both ZnPPIX-DME molecules and AuNPs. Those interactions are a key factor allowing the co-deposition of both AuNPs and ZnPPIX-DME molecules onto a solid substrate, thus forming the LB film. SERS of ZnPPIX-DME was successfully attained, ensuring the spatial distribution of the AuNPs. Higher enhancement factors were found at AuNP aggregates, as a result of the intense local electromagnetic field found in the metal nanoparticle aggregates. The main vibrational bands observed in the SERS spectra suggest a physical adsorption of the ZnPPIX-DME onto the surface of AuNPs. The latter is not only in agreement with the interactions pointed out by the pi-A isotherms but also suggests that this interaction is kept upon LB film co-deposition.