• 文献标题:   Templating effect of single-layer graphene supported by an insulating substrate on the molecular orientation of lead phthalocyanine
  • 文献类型:   Article
  • 作  者:   MADHURI KP, SAGADE AA, SANTRA PK, JOHN NS
  • 作者关键词:   conducting atomic force microscopy cafm, lead phthalocyanine pbpc, molecular orientation, singlelayer graphene, substrate effect, twodimensional grazing incidence xray diffraction 2dgixrd
  • 出版物名称:   BEILSTEIN JOURNAL OF NANOTECHNOLOGY
  • ISSN:   2190-4286
  • 通讯作者地址:   Ctr Nano Soft Matter Sci
  • 被引频次:   1
  • DOI:   10.3762/bjnano.11.66
  • 出版年:   2020

▎ 摘  要

The influence of single-layer graphene on top of a SiO2/Si surface on the orientation of nonplanar lead phthalocyanine (PbPc) molecules is studied using two-dimensional grazing incidence X-ray diffraction. The studies indicate the formation of a mixture of polymorphs, i.e., monoclinic and triclinic forms of PbPc with face-on (lying down) and edge-on (standing up) PbPc orientations, respectively. The formation of monoclinic fractions is attributed to the presence of the graphene layer directing the TF interactions between the highly delocalized macrocycles. The competing interfacial van der Waals forces and molecule-molecule interactions lead to the formation of a small fraction of triclinic moieties. The nanoscale electrical characterization of the thin PbPc layer on graphene by means of conducting atomic force microscopy shows enhanced vertical conductance with interconnected conducting domains consisting of ordered monoclinic crystallites through which the charge transfer occurs via tunneling. These results show the importance of a templating layer to induce the formation of a required phase of PbPc suitable for specific device applications.