Electronic and structural properties at the interface between CuPc and graphene

Abstract

The electronic and structural properties at Copper phthalocyanine (CuPc)/graphene have been studied using ultraviolet photoemission spectroscopy and first-principles density function theory calculation. The five emission features α, β, γ, δ, and ε originating from the CuPc molecules locate at 1.48, 3.66, 4.98, 6.90, and 9.04 eV, respectively. These features shift in binding energy with the increasing CuPc coverage. The feature α is mostly deriving from Cu 3d orbital with some contributions from C 2p orbital. Further theoretical calculation indicates that the adsorption of CuPc on a top site is the most favorable configuration, and the separation between the adsorbate and graphene is about 3.47 Å. According to the density of states before and after CuPc adsorption, the LUMO of CuPc is slightly occupied, while the Dirac point of graphene slightly shift towards higher energy, suggesting that a small amount of electron transfer from graphene to CuPc upon contact.

Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene

“…The energy differences between “ top ” and “ hollow ” geometries are in general less than 0.2 eV (Supporting Information Table S1), which is within the computational uncertainty. This is an indication that there is no preferential position on the hexagonal lattice, as already mentioned in previous computational studies . The difference of Δ E int between the “molecular” and periodical approaches is about 0.5 eV for CoP on a monolayer graphene, and about 1 eV for CoPc.…”

Raman enhancement on ultra-clean graphene quantum dots produced by quasi-equilibrium plasma-enhanced chemical vapor deposition

“…The optimized values for the distance between the absorbed R6G and corresponding substrates were 4.053 Å (ZZ09), 3.880 Å (ZZ25), and 5.133 Å (Graphene). The optimized geometrical condition with the CuPc being absorbed at the hollow site on GQD and graphene was adopted 56 . The optimized values for the distance between the absorbed CuPc and the GQD/graphene substrates were 3.588 Å (ZZ09), 3.741 Å (ZZ25), and 4.341 Å (Graphene).…”

Surface chemistry of porphyrins and phthalocyanines

“…A small charge transfer from CoPc to the Ru substrate was reported [300]. Monolayer graphene transferred to a SiO 2 /Si support was used as a substrate for CuPc monolayers in a combined UPS and DFT study, which revealed preferential adsorption on top sites and a slight occupation of the LUMO of CuPc [630]. Similar as for ZnEtioI on Al 2 O 3 /Ni 3 Al(111) [536] mentioned in this section above, luminescence induced by tunneling electrons was observed for third-layer 2HTBPP on graphene/Ru(0001).…”