Electronic structure of an iron porphyrin derivative on Au(1 1 1)

Abstract

Surface-bound porphyrins are promising candidates for molecular switches, electronics and spintronics. Here, we studied the structural and the electronic properties of Fe-tetra-pyridil-porphyrin adsorbed on Au(111) in the monolayer regime. We combined scanning tunneling microscopy/spectroscopy, ultraviolet photoemission, and two-photon photoemission to determine the energy levels of the frontier molecular orbitals. We also resolved an excitonic state with a binding energy of 420 meV, which allowed us to compare the electronic transport gap with the optical gap.

Synthesis and photophysics of new pyridyl end-capped 3D-dithia[3.3]paracyclophane-based Janus tectons: surface-confined self-assembly of their model pedestal on HOPG

“…This is consistent with the principles of interactions between adsorbed molecules with pyridyl and alkyl terminations. 15 Such pyridyl-driven assemblies has been observed for molecules bearing two [26][27][28] but also three [29][30][31] and even four pyridine entities 32 . The proposed scheme [figure 7 (d) ] is fully consistent with the assembly of short bivalent pyridyl-terminated rod-shaped molecules [FC5].…”

Electronic Properties of Tetraazaperopyrene Derivatives on Au(111): Energy-Level Alignment and Interfacial Band Formation

“…Similar shifts have been observed for many organic molecules on Au(111), where charge transfer to the substrate is negligible and ascribed to a modification of the image charge and work function (Φ). 13 , 53 , 82 − 87 Indeed, we find a reduction of the work function for all three molecules, the largest one for TAPP-H by 0.74 eV.…”

Electronic Properties of Tetraazaperopyrene Derivatives on Au(111): Energy Level Alignment and Interfacial Band Formation

“…The IP can be determined by photoemission spectroscopies (e.g. ultraviolet photoemission spectroscopy (UPS), [6][7][8][9] two-photon photoemission (2PPE) [10][11][12][13] ), or scanning tunneling spectroscopy (STS). 14 For the identification of affinity levels, inverse photoemission, 15,16 2PPE or STS can be used.…”

“…), which is different from the optical gap (HOMO-LUMO transition leading to exciton formation). 17 The latter can be determined in surface-adsorbed molecules with 2PPE, [10][11][12][13]18 differential reflectance spectroscopy [19][20][21][22] or high resolution electron energy loss spectroscopy. 18,[23][24][25][26][27][28][29] The electronic structure of free (gas phase) molecules is strongly affected in the condensed phase and in particular when the molecules are adsorbed on metal surfaces.…”