Centro de Investigaciones en Bionanociencias (CIBION), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) , Godoy Cruz 2390, C1425FQD Ciudad de Buenos Aires, Argentina.
The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
Nano Lett. 2017 Sep 13;17(9):5747-5755. doi: 10.1021/acs.nanolett.7b02713. Epub 2017 Aug 17.
Optical printing holds great potential to enable the use of the vast variety of colloidal nanoparticles (NPs) in nano- and microdevices and circuits. By means of optical forces, it enables the direct assembly of NPs, one by one, onto specific positions of solid surfaces with great flexibility of pattern design and no need of previous surface patterning. However, for unclear causes it was not possible to print identical NPs closer to each other than 300 nm. Here, we show that the repulsion restricting the optical printing of close by NPs arises from light absorption by the printed NPs and subsequent local heating. By optimizing heat dissipation, it is possible to reduce the minimum separation between NPs. Using a reduced graphene oxide layer on a sapphire substrate, we demonstrate for the first time the optical printing of Au-Au NP dimers. Modeling the experiments considering optical, thermophoretic, and thermo-osmotic forces we obtain a detailed understanding and a clear pathway for the optical printing fabrication of complex nano structures and circuits based on connected colloidal NPs.
光学打印在纳米和微器件和电路中具有很大的潜力，可以使用各种胶体纳米粒子 (NPs)。通过光学力，可以将 NPs 一个一个地直接组装到固体表面的特定位置，具有图案设计的极大灵活性，并且不需要预先进行表面图案化。然而，由于不清楚的原因，无法将彼此之间的距离更近的相同 NPs 打印出来，其距离小于 300nm。在这里，我们表明限制近邻 NPs 光学打印的排斥力来自于被打印 NPs 的光吸收和随后的局部加热。通过优化散热，可以减小 NPs 之间的最小间隔。使用蓝宝石衬底上的还原氧化石墨烯层，我们首次演示了 Au-Au NP 二聚体的光学打印。通过考虑光学、热泳和热渗透力的实验建模，我们获得了对基于连接胶体 NPs 的复杂纳米结构和电路的光学打印制造的详细理解和明确途径。
