Department of Chemistry, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
Department of Photonics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
Sci Rep. 2017 Jun 20;7(1):3908. doi: 10.1038/s41598-017-04139-0.
Demand for rapid and massive-scale exfoliation of bulky graphite remains high in graphene commercialization and property manipulation. We report a procedure utilizing "preformed acidic oxidizing medium (PAOM)" as a modified version of the Hummers' method for fast and reliable synthesis of graphene oxide. Pre-mixing of KMnO and concentrated HSO prior to the addition of graphite flakes enables the formation of effectively and efficiently oxidized graphene oxide (EEGO) featured by its high yields and suspension homogeneity. PAOM expedites diffusion of the Mn-oxidants into the graphite galleries, resulting in the rapid graphite oxidation, capable of oxidizing bulky graphite flakes (~0.8 mm in diameter) that can not be realized by the Hummers' method. In the scale-up tests, ten-time amount of graphite can be completely exfoliated by PAOM without need of extended reaction time. The remarkable suspension homogeneity of EEGO can be exploited to deposit ultra-flat coating for wafer-scale nanopatterning. We successfully fabricated GO optical gratings with well-defined periodicity (300 nm) and uniform thickness (variation <7 nm). The combination of the facile and potent PAOM approach with the wafer-scale patterning technique may realize the goal for massive throughput graphene nanoelectronics.
在商业化和性能处理石墨烯的过程中，对快速大规模剥离块状石墨的需求仍然很高。我们报告了一种利用“预先形成的酸性氧化介质（PAOM）”作为 Hummers 法的改进版本，快速可靠地合成氧化石墨烯的方法。在加入石墨薄片之前，预先混合 KMnO 和浓 HSO，可形成有效且高效氧化的石墨烯氧化物（EEGO），其产率高，悬浮液均匀。PAOM 促进了 Mn-氧化剂向石墨层间的扩散，从而实现了快速石墨氧化，这是 Hummers 法无法实现的，可以氧化大块石墨薄片（直径约 0.8 毫米）。在放大测试中，PAOM 可完全剥离十倍量的石墨，而无需延长反应时间。EEGO 的显著悬浮均匀性可用于沉积超平整涂层，实现晶圆级纳米图案化。我们成功制备了具有良好定义的周期性（300nm）和均匀厚度（变化<7nm）的 GO 光学光栅。简便且有效的 PAOM 方法与晶圆级图案化技术的结合，可能实现大规模生产石墨烯纳米电子学的目标。
