Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47906, USA.
School of Industrial Engineering, Purdue University, West Lafayette, IN, 47906, USA.
Adv Mater. 2018 Mar;30(11). doi: 10.1002/adma.201705840. Epub 2018 Jan 22.
Ongoing efforts in triboelectric nanogenerators (TENGs) focus on enhancing power generation, but obstacles concerning the economical and cost-effective production of TENGs continue to prevail. Micro-/nanostructure engineering of polymer surfaces has been dominantly utilized for boosting the contact triboelectrification, with deposited metal electrodes for collecting the scavenged energy. Nevertheless, this state-of-the-art approach is limited by the vague potential for producing 3D hierarchical surface structures with conformable coverage of high-quality metal. Laser-shock imprinting (LSI) is emerging as a potentially scalable approach for directly surface patterning of a wide range of metals with 3D nanoscale structures by design, benefiting from the ultrahigh-strain-rate forming process. Here, a TENG device is demonstrated with LSI-processed biomimetic hierarchically structured metal electrodes for efficient harvesting of water-drop energy in the environment. Mimicking and transferring hierarchical microstructures from natural templates, such as leaves, into these water-TENG devices is effective regarding repelling water drops from the device surface, since surface hydrophobicity from these biomicrostructures maximizes the TENG output. Among various leaves' microstructures, hierarchical microstructures from dried bamboo leaves are preferable regarding maximizing power output, which is attributed to their unique structures, containing both dense nanostructures and microscale features, compared with other types of leaves. Also, the triboelectric output is significantly improved by closely mimicking the hydrophobic nature of the leaves in the LSI-processed metal surface after functionalizing it with low-surface-energy self-assembled-monolayers. The approach opens doors to new manufacturable TENG technologies for economically feasible and ecologically friendly production of functional devices with directly patterned 3D biomimic metallic surfaces in energy, electronics, and sensor applications.
目前，摩擦纳米发电机（TENG）的研究重点在于提高其发电效率，但 TENG 的经济高效生产仍然面临诸多障碍。聚合物表面的微纳结构工程主要用于增强接触式摩擦起电，同时使用沉积的金属电极来收集收集收集的能量。然而，这种最先进的方法受到生产具有高质量金属 conformal 覆盖的 3D 分层表面结构的潜力的限制。激光冲击压印（LSI）作为一种具有潜力的可扩展方法，通过设计可以直接在各种金属表面形成 3D 纳米结构，得益于超高应变速率的成形工艺。在这里，展示了一种具有 LSI 处理的仿生分层结构金属电极的 TENG 器件，用于有效地收集环境中的水滴能量。通过模仿和转移自然模板（如树叶）中的分层微观结构，可以有效地将水滴从器件表面排斥出去，因为这些仿生微结构具有疏水性，可以最大化 TENG 的输出。在各种树叶的微观结构中，与其他类型的树叶相比，干竹叶的分层微观结构更有利于最大化功率输出，这归因于其独特的结构，包含密集的纳米结构和微尺度特征。此外，通过在功能化的低表面能自组装单层上紧密模仿 LSI 处理后的金属表面的疏水性，可以显著提高摩擦电输出。该方法为经济可行且环保的功能性器件的制造开辟了新途径，这些器件具有直接图案化的 3D 仿生金属表面，可应用于能源、电子和传感器领域。
