Symmetry-selective ultrafast charge transfer via cyano end groups at the PDIF-CN▫$_2$▫–Au(111) interfaceKladnik, Gregor (Avtor) Cassinese, Antonio (Avtor) Schio, Luca (Avtor) Goldoni, Andrea (Avtor) Morgante, Alberto (Avtor) Floreano, Luca (Avtor) Cvetko, Dean (Avtor) thin filmsinterfacescharge transferAuger spectroscopyCyano-functionalized perylene diimides provide a platform for engineering orbital-specific electronic transparency at organic‒metal interfaces. Here we resolve the adsorption geometry, orbital symmetry, and ultrafast charge-transfer dynamics of PDIF-CN▫$_2$▫ on Au(111) using polarization-dependent NEXAFS, XPS, resonant Auger spectroscopy with core-hole-clock analysis, and STM. Molecules in the monolayer lie flat with out-of-molecular plane polarized cyano-derived ▫$\pi^*$▫ orbitals aligned toward Au(111). Although the overall electronic structure remains largely molecular, the nearly degenerate cyano ▫$\sigma^*(\pi)/\pi^*(\pi)$▫ doublet becomes distinctly split at the interface, enabling symmetry-selective coupling of cyano orbitals. We use Auger spectator shifts to quantify bidirectional charge exchange within the N 1s core-hole lifetime, yielding injection of ▫$\sim$▫0.43 e▫$^-$▫ from Au into cyano ▫$\pi^*(\pi)$▫ orbital and the transfer of ▫$\sim$▫0.17 e▫$^-$▫ in the opposite direction. These findings establish cyano end groups as symmetry-selective gateways for femtosecond charge transfer at molecule‒metal interfaces.20262026-06-04 11:56:11Članek v reviji183097UDK: 544ISSN pri članku: 1530-6984DOI: 10.1021/acs.nanolett.6c01061COBISS_ID: 278874883sl