基于全氟酞菁铜和碗烯双分子体系在银和石墨表面自组装行为的低温扫描隧道显微镜研究（英文）

LT-STM Investigation of the Self-Assembled F_(16)CuPc-Corannulene Binary System on Ag(111) and Graphite Surfaces

由于其独特的分子构型和电子结构,碗烯被认为是组成有机分子电子器件的一种重要的结构单元。在不同金属表面上单一组分的碗烯或其衍生物进行自组装的行为,及其所形成自组装薄膜的电子结构已经被广泛研究。这里我们利用低温扫描隧道显微镜(LT-STM),对全氟酞菁铜和碗烯两种组分在高定向热解石墨和银(111)两种不同衬底上的自组装结构进行了报道。在石墨衬底上,全氟酞菁铜和碗烯分子间形成的氢键成为双分子网络结构能够形成的关键;同时,由于这种分子间氢键的存在,碗烯分子大多采取"开口朝下"的空间构型,以保证分子间氢键最大限度的形成。但在银衬底上观察到的碗烯分子则随机采取"开口向上"或"开口向下"两种构型,并没有一种优势构型的存在。我们认为此时银(111)衬底和有机分子间强烈的相互作用限制了碗烯两种构型之间的翻转,使得碗烯分子一旦被吸附就只能保持其原本的构型,从而导致了在结果上两种构型的随机分布。

Corannulene （COR） is considered a promising molecular building block for organic electronics owing to its intriguing geometrical and electronic properties. Intensive research efforts have been devoted to understanding the assembly behavior and electronic structure of COR and its derivatives on various metal surfaces via low-temperature scanning tunneling microscopy （LT-STM）. Here we report the formation of binary molecular networks of copper hexadecafluorophthalocyanine （F16CuPc）-COR self-assembled on the highly oriented pyrolytic graphite （HOPG） and Ag（111） substrates. Intermolecular hydrogen bonding between F16CuPc and COR facilitates the formation of binary molecular networks on HOPG and further induces a preference for bowl-down configured COR molecules. This observed configuration preference disappears on Ag（111） substrate, where COR molecules lie on the substrate with their bowl openings pointing up and down randomly. We propose that strong interfacial interactions between the molecule and Ag（111 ） surface constrain the bowl inversion of the COR molecule, which thus retains its initial configuration upon adsorption.