Tuning the surface plasmon on Ag(111) by organic molecules

Abstract

Extraordinary transmission of organic photoluminescence through an otherwise opaque metal layer via surface plasmon cross couplingThe surface plasmon dispersion of Ag(111) tuned by adsorption of F4-TCNQ molecules has been investigated using high resolution electron energy loss spectroscopy. For the pristine Ag(111) film, the surface plasmon energy shows a positive quadratic dispersion. After adsorption of F4-TCNQ, the plasmon energy of Ag decreases significantly and the dispersion switches sign at small q jj . The deviation systematically increases with the coverage of F4-TCNQ. These behaviors are explained by charge transfer between the Ag substrate and the molecular gas layer. V C 2012 American Institute of Physics. [http://dx.

Interplay between single-particle and plasmonic excitations in the electronic response of thin Ag films

“…Contrary to the latter systems, in silver a strong lowering of the SP energy and a positive dispersion as a function of the parallel momentum transfer [22][23][24][25][26][27] are observed. Despite the wealth of papers on Ag plasmons [28][29][30][31][32], currently the nature of a peak at 7-8 eV still remains controversial. It was ascribed to: the bulk plasmon (BP) [33], the MP [34], the free-electron SP [33,35], or an interband transition [36][37][38].…”

Kinetic Study on the Adsorption of 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag Nanoparticles in Chloroform: Implications for the Charge Transfer Complex of Ag–F4TCNQ

“…42 Therefore, the Femi energy level of Ag NPs is located higher than the lowest unoccupied molecular orbital (LUMO) of F 4 TCNQ, resulting in the direct injection of the electrons from Ag NPs to F 4 TCNQ upon adsorption. 43 The intensities of these anion absorption peaks increase gradually along with the molar ratio of F 4 TCNQ molecules to Ag NPs. When the concentration of F 4 TCNQ molecules reaches 12.0 μM, a new peak at 615.0 nm appears, which is derived from the presence of the Ag−F 4 TCNQ complex.…”

“…As exemplified in the energy-level diagram of Ag NPs and F 4 TCNQ (inset of Figure c), the electron affinity of the F 4 TCNQ molecule is 4.93 eV and the work function of Ag NPs is 4.5 eV . Therefore, the Femi energy level of Ag NPs is located higher than the lowest unoccupied molecular orbital (LUMO) of F 4 TCNQ, resulting in the direct injection of the electrons from Ag NPs to F 4 TCNQ upon adsorption . The intensities of these anion absorption peaks increase gradually along with the molar ratio of F 4 TCNQ molecules to Ag NPs.…”

Symmetry, Shape, and Energy Variations in Frontier Molecular Orbitals at Organic/Metal Interfaces: The Case of F4TCNQ

“…Molecules with strongly donor or acceptor character may induce a sizeable interface charge transfer, of the order of one electron per molecule, which can both trigger profound electronic and conformational molecular changes [11][12][13] and modify the substrate properties. 14 These are attractive cases, which could prompt to the emergence of exotic interface properties, such as superconductivity or magnetism. [15][16][17] In the quest for functional organic/metal interfaces, the combination of planar, aromatic molecules and noble metal surfaces has several advantages, particularly as model research systems.…”

“…However, enhanced molecule/surface interactions lead to larger hybridization effects , and even induce structural disruptions of the substrate, such as atomic segregation, making interface electronic states less predictable. Molecules with strongly donor or acceptor character may induce a sizable interface charge transfer, of the order of one electron per molecule, which can both trigger profound electronic and conformational molecular changes − and modify the substrate properties . These are attractive cases, which could prompt to the emergence of exotic interface properties, such as superconductivity or magnetism. − …”