Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Prague, Czechia.
Photonics & Quantum Materials Center, Skolkovo Institute of Science and Technology, Nobel Street 3, Moscow 143025, Russia.
Nanoscale. 2023 Feb 16;15(7):3351-3365. doi: 10.1039/d2nr06680g.
Photoluminescent gold nanoclusters are widely seen as a promising candidate for applications in biosensing and bioimaging. Although they have many of the required properties, such as biocompatibility and photostability, the luminescence of near infrared emitting gold nanoclusters is still relatively weak compared to the best available fluorophores. This study contributes to the ongoing debate on the possibilities and limitations of improving the performance of gold nanoclusters by combining them with plasmonic nanostructures. We focus on a detailed description of the emission enhancement and compare it with the excitation enhancement obtained in recent works. We prepared a well-defined series of gold nanoclusters attached to gold nanorods whose plasmonic band is tuned to the emission band of gold nanoclusters. In the resultant single-element hybrid nanostructure, the gold nanorods control the luminescence of gold nanoclusters in terms of its spectral position, polarization and lifetime. We identified a range of parameters which determine the mutual interaction of both particles including the inter-particle distance, plasmon-emission spectral overlap, dimension of gold nanorods and even the specific position of gold nanoclusters attached on their surface. We critically assess the practical and theoretical photoluminescence enhancements achievable using the above strategy. Although the emission enhancement was generally low, the observations and methodology presented in this study can provide a valuable insight into the plasmonic enhancement in general and into the photophysics of gold nanoclusters. We believe that our approach can be largely generalized for other relevant studies on plasmon enhanced luminescence.
光致发光金纳米团簇被广泛认为是在生物传感和生物成像应用中有前途的候选物。尽管它们具有许多所需的性质，如生物相容性和光稳定性，但与现有的最佳荧光团相比，近红外发射金纳米团簇的发光仍然相对较弱。本研究有助于正在进行的关于通过将金纳米团簇与等离子体纳米结构结合来提高其性能的可能性和局限性的辩论。我们专注于对发射增强的详细描述，并将其与最近的工作中获得的激发增强进行比较。我们制备了一系列附着在金纳米棒上的具有明确结构的金纳米团簇，其等离子体带调谐到金纳米团簇的发射带。在所得的单元素混合纳米结构中，金纳米棒控制金纳米团簇的发光，包括其光谱位置、偏振和寿命。我们确定了一系列决定两个粒子相互作用的参数，包括粒子间距离、等离子体发射光谱重叠、金纳米棒的尺寸，甚至附着在表面上的金纳米团簇的特定位置。我们批判性地评估了使用上述策略实现的实际和理论上的光致发光增强。虽然发射增强通常较低，但本研究中提出的观察结果和方法可以为等离子体增强的一般情况以及金纳米团簇的光物理提供有价值的见解。我们相信我们的方法可以在很大程度上推广到其他相关的等离子体增强发光研究中。
