Abstract Demand for an effective strategy for exfoliating layered materials into flakes without perturbing their intrinsic structure is growing. Herein, we introduce an effective fabrication method of large-sized non-oxidized graphene flakes (NOGFs) as a representative example of a general strategy using spontaneous insertion of exfoliating medium into a layered material. We fabricated a ternary graphite intercalation compound (t-GIC) with stoichiometry of KC24(THF)2, and analyzed its morphology and electronic structure through experimental and computational approach. Interactions between the t-GIC and aprotic organic solvents with different polarities were investigated, where a unique swelling behavior was observed with dimethyl sulfoxide (DMSO). Based on the analysis of the phenomena, we demonstrate facile exfoliation of the t-GIC in polyvinyl pyrrolidone (PVP)-DMSO solution for fabrication of highly crystalline and large-sized NOGFs. The lateral size of the NOGFs ranges over 30 μm, while the 98% having thickness below 10 layers. The NOGF film exhibits supreme electrical conductivity of 3.36 × 105 S/m, which is, to our best knowledge, the highest value for a thin conductive film made of graphene flakes.

中文翻译：

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基于自发溶剂插入石墨插层化合物的超大非氧化石墨烯薄片

摘要 对将层状材料剥离成薄片而不干扰其内在结构的有效策略的需求正在增长。在此，我们介绍了一种有效的大尺寸非氧化石墨烯薄片 (NOGFs) 制造方法，作为使用自发将去角质介质插入层状材料的一般策略的代表性示例。我们制备了化学计量为 KC24(THF)2 的三元石墨插层化合物 (t-GIC)，并通过实验和计算方法分析了其形态和电子结构。研究了 t-GIC 和具有不同极性的非质子有机溶剂之间的相互作用，其中使用二甲基亚砜 (DMSO) 观察到了独特的溶胀行为。根据现象分析，我们展示了聚乙烯吡咯烷酮 (PVP)-DMSO 溶液中 t-GIC 的轻松剥离，用于制造高结晶度和大尺寸的 NOGF。NOGFs 的横向尺寸范围超过 30 μm，而 98% 的厚度低于 10 层。NOGF 膜表现出 3.36 × 105 S/m 的最高电导率，据我们所知，这是由石墨烯薄片制成的薄导电膜的最高值。