Bilayer graphene consists of two stacked graphene layers bound together by van der Waals interaction. As the molecular analog of bilayer graphene, molecular bilayer graphene (MBLG) can offer useful insights into the structural and functional properties of bilayer graphene. However, synthesis of MBLG, which requires discrete assembly of two graphene fragments, has proved to be challenging. Here, we show the synthesis and characterization of two structurally well-defined MBLGs, both consisting of two π−π stacked nanographene sheets. We find they have excellent stability against variation of concentration, temperature and solvents. The MBLGs show sharp absorption and emission peaks, and further time-resolved spectroscopic studies reveal drastically different lifetimes for the bright and dark Davydov states in these MBLGs.

双层石墨烯由通过范德华相互作用相互作用结合在一起的两个堆叠的石墨烯层组成。作为双层石墨烯的分子类似物，分子双层石墨烯（MBLG）可以提供有关双层石墨烯的结构和功能特性的有用见解。然而，已证明需要将两个石墨烯片段离散组装的MBLG合成具有挑战性。在这里，我们显示了两个结构明确的MBLG的合成和表征，它们都由两个π-π堆叠的纳米石墨烯片组成。我们发现它们对浓度，温度和溶剂的变化具有出色的稳定性。MBLG显示出尖锐的吸收和发射峰，进一步的时间分辨光谱研究表明，这些MBLG中亮和暗的达维多夫态的寿命截然不同。