TY - JOUR
T1 - Barrier height formation for the PTCDA/Au(1 1 1) interface
AU - Martínez, J. I.
AU - Abad, E.
AU - Flores, F.
AU - Ortega, J.
AU - Brocks, G.
PY - 2011/11/18
Y1 - 2011/11/18
N2 - A Density Functional calculation is performed to analyze the PTCDA/Au(1 1 1) interface, including the effect of the molecular charging energy on the transport gap. The calculated transport gap is 2.9 eV, and the lowest unoccupied molecular orbital, or LUMO, level is found at 4.25 eV below the vacuum level. We show that the alignment between the metal and the organic levels is controlled by the charge transfer between the two materials, as determined by the difference between the molecule Charge Neutrality Level, or CNL, (located 0.3 eV below the LUMO level) and the metal work function. We compare with independent General Gradient Approximation-Density Functional calculations, DFT-GGA, yielding an energy gap of 1.4 eV; we find, however, good agreement between both approaches for the CNL and the interface potential step. Good agreement is also found between our results and the experimental evidence.
AB - A Density Functional calculation is performed to analyze the PTCDA/Au(1 1 1) interface, including the effect of the molecular charging energy on the transport gap. The calculated transport gap is 2.9 eV, and the lowest unoccupied molecular orbital, or LUMO, level is found at 4.25 eV below the vacuum level. We show that the alignment between the metal and the organic levels is controlled by the charge transfer between the two materials, as determined by the difference between the molecule Charge Neutrality Level, or CNL, (located 0.3 eV below the LUMO level) and the metal work function. We compare with independent General Gradient Approximation-Density Functional calculations, DFT-GGA, yielding an energy gap of 1.4 eV; we find, however, good agreement between both approaches for the CNL and the interface potential step. Good agreement is also found between our results and the experimental evidence.
KW - Charging energy
KW - Density-Functional Theory
KW - Metal-organic interfaces
KW - PTCDA
UR - http://www.scopus.com/inward/record.url?scp=81555213585&partnerID=8YFLogxK
U2 - 10.1016/j.chemphys.2011.09.018
DO - 10.1016/j.chemphys.2011.09.018
M3 - Article
SN - 0301-0104
VL - 390
SP - 14
EP - 19
JO - Chemical physics
JF - Chemical physics
IS - 1
ER -