Sum-Frequency Generation Spectra of Thin Organic Films on Silver Enhanced Due to Surface Plasmon Excitation

Abstract

We have studied vibrational spectra of thin films of copper phthalocyanine and fullerene of different thicknesses on silver obtained by a visible‐infrared sum‐frequency generation (SFG). The free electron laser FELIX was used as a source of broadband infrared and the pulsed Nd:YLF laser system as a source of visible radiation. Excitation of a surface plasmon on silver has allowed to enhance the efficiency of the SFG process. The SFG signal has appeared to be almost independent of the film thickness demonstrating the exclusive contribution of the interfacial layer to the SFG signal.

Vibrational Sum Frequency Generation Spectroscopy of Fullerene at Dielectric Interfaces

“…Clearly the gas-phase calculations do not capture the symmetry breaking that occurs at the interfaces of a film of C 60 since VSFG spectra have been reported by others. [14][15][16][17]43 Figure 2a shows the VSFG spectra collected in the current study with an ssp polarization combination (s = VSFG, s = visible, p = IR) on native oxide (SiO 2 ) over silicon and on a CaF 2 substrate. The spectra on dielectric substrates are quite different from those reported by others on metal surfaces, 14−17 and the spectrum on CaF 2 is also surprisingly different from that of the SiO 2 sample.…”

Controlling the Optical Properties of Plasmonic Disordered Nanohole Silver Films

“…For applications that require the silver films to remain conductive over long ranges, the maximum photon harvesting coverage has already been determined from the electrode data presented here to be ϳ0. 4.…”

“…Surface plasmons (SP), collective electron oscillations at the surface of noble metals, have demonstrated tremendous potential as a route to tailor and selectively amplify myriad optical phenomena in molecular thin films. − A simple method for the integration of plasmon active materials into opto-electronic devices is the addition of metal nanoparticles. ,− An alternate route to introduce plasmon effects is the addition of subwavelength scale holes in a metal surface. − We have recently used this approach in an organic photovoltaic device . Here we present a thorough characterization of the electrical and optical properties of random nanohole arrays as a function of hole density.…”

Momentum Relaxed, Plasmon-Resonant Vibrational Sum Frequency Generation of Electrochemical Interfaces: Direct Observation of Carbon Dioxide Electroreduction on Gold

“…This result may seem surprising because the simulated resonance angle for the CaF 2 /Au/water interface is 73 • , and our working angle is 56 • relative to surface normal. However, this result can be explained by the plasmonic grating coupling effect, [31][32][33][34] which predicts that a structured or roughened surface, in this case the CaF 2 /Au interface, will relax the strict momentum matching requirement allowing coupling of the incident electric field to SPR modes across a range of incidence angles.…”