Andersson Carl, Serebrennikova Olga, Tiburski Christopher, Alekseeva Svetlana, Fritzsche Joachim, Langhammer Christoph
Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
ConScience AB, Läraregatan 3, 411 33 Göteborg, Sweden.
ACS Nano. 2023 Aug 22;17(16):15978-15988. doi: 10.1021/acsnano.3c04147. Epub 2023 Aug 3.
Alloying offers an increasingly important handle in nanomaterials design in addition to the already widely explored size and geometry of nanostructures of interest. As the key trait, the mixing of elements at the atomic level enables nanomaterials with physical or chemical properties that cannot be obtained by a single element alone, and subtle compositional variations can significantly impact these properties. Alongside the great potential of alloying, the experimental scrutiny of its impact on nanomaterial function is a challenge because the parameter space that encompasses nanostructure size, geometry, chemical composition, and structural atomic-level differences among individuals is vast and requires unrealistically large sample sets if statistically relevant and systematic data are to be obtained. To address this challenge, we have developed a microshutter device for spatially highly resolved physical vapor deposition in the lithography-based fabrication of nanostructured surfaces. As we demonstrate, it enables establishing compositional gradients across a surface with single nanostructure resolution in terms of alloy composition, which subsequently can be probed in a single experiment. As a showcase, we have nanofabricated arrays of AuAg, AuPd, and AgPd alloy nanoparticles with compositions systematically controlled at the level of single particle rows, as verified by energy dispersive X-ray and single particle plasmonic nanospectroscopy measurements, which we also compared to finite-difference time-domain simulations. Finally, motivated by their application in state-of-the-art plasmonic hydrogen sensors, we investigated PdAu alloy gradient arrays for their hydrogen sorption properties. We found distinctly composition-dependent kinetics and hysteresis and revealed a composition-dependent contribution of a single nanoparticle response to the ensemble average, which highlights the importance of alloy composition screening in single experiments with single nanoparticle resolution, as offered by the microshutter nanofabrication approach.
除了已经被广泛探索的目标纳米结构的尺寸和几何形状外，合金化在纳米材料设计中提供了一个越来越重要的手段。作为关键特性，原子水平上元素的混合使纳米材料具有单一元素无法获得的物理或化学性质，并且细微的成分变化会显著影响这些性质。除了合金化的巨大潜力外，对其对纳米材料功能影响的实验研究是一项挑战，因为包含纳米结构尺寸、几何形状、化学成分以及个体之间结构原子水平差异的参数空间非常大，如果要获得具有统计相关性和系统性的数据，则需要不切实际的大量样本集。为了应对这一挑战，我们开发了一种微快门装置，用于在基于光刻的纳米结构表面制造中进行空间高分辨率物理气相沉积。正如我们所展示的，它能够在合金成分方面以单纳米结构分辨率在整个表面上建立成分梯度，随后可以在单个实验中进行探测。作为一个展示，我们通过能量色散X射线和单粒子等离子体纳米光谱测量验证，纳米制造了AuAg、AuPd和AgPd合金纳米粒子阵列，其成分在单粒子行的水平上得到系统控制，我们还将其与有限时域差分模拟进行了比较。最后，受其在最先进的等离子体氢传感器中的应用启发，我们研究了PdAu合金梯度阵列的氢吸附特性。我们发现了明显的成分依赖性动力学和滞后现象，并揭示了单个纳米粒子响应对方差平均值的成分依赖性贡献，这突出了在微快门纳米制造方法提供的具有单纳米粒子分辨率的单个实验中进行合金成分筛选的重要性。
