Abstract：
Optical-induced shape transformation of single nanoparticles on substrates has shown benefits of simplicity and regularity for single-particle device fabrication and on-chip integration. However, most of the existing strategies are based on wet chemical growth and etching, which could lead to surface contamination with limited local selectivity and device compatibility. Shape deformation via the photothermal effect can overcome these issues but has limited versatility and tunability largely due to the high surface tension of the molten droplet. Here we show gold nanoparticles (Au NPs) can drastically transform into nanoplates under the irradiation of a continuous wave laser (446 nm). We reveal the dielectric thin film underneath the molten Au is critical in deforming the NP into faceted nanoplate under the drive of photothermophoretic forces, which is sufficient to counteract the surface tension of the molten droplet. Both experimental evidence and simulations support this thin-film-assisted photothermal deformation mechanism, which is local selective and generally applicable to differently shaped Au NPs. It provides a facile and robust strategy for single-plate-based device applications.
摘要：
衬底上单个纳米颗粒的光学诱导形状转变已经显示出对于单颗粒器件制造和芯片上集成的简单性和规则性的益处。然而,大多数现有的策略是基于湿化学生长和蚀刻，这可能导致表面污染，局部选择性和设备兼容性有限。经由光热效应的形状变形可以克服这些问题,但是很大程度上由于熔融液滴的高表面张力而具有有限的通用性和可调性。在这里，我们显示金纳米粒子（AuNPs）可以在连续波激光（446nm）的照射下急剧转变为纳米板。我们发现，在光热泳力的驱动下，熔融Au下方的介电薄膜对于将NP变形为多面纳米板至关重要，这足以抵消熔滴的表面张力。实验证据和模拟都支持这种薄膜辅助光热变形机制，这是局部选择性的，通常适用于不同形状的AuNP。它为基于单板的设备应用提供了一个简单而强大的策略。
