Probing the electrode-polymer interface in conjugated polymer devices with surface-enhanced Raman scattering

Abstract

The role of cesium carbonate on the electron injection and transport enhancement in organic layer by admittance spectroscopy Appl. Phys. Lett. 101, 193303 (2012) The role of cesium carbonate on the electron injection and transport enhancement in organic layer by admittance spectroscopy APL: Org. Electron. Photonics 5, 243 (2012) Growth and characterization of n-type electron-induced ferromagnetic semiconductor (In,Fe)As Appl. Phys. Lett. 101, 182403 (2012) Probing interfacial charge accumulation in ITO/α-NPD/Alq3/Al diodes under two electroluminescence operational modes by electric-field induced optical second-harmonic generation

Surface-Enhanced Raman Scattering of MEH-PPV on Gold and Silver Nanoparticles

“…There is no significant shift of the bands of SERS spectra of MEH-PPV compared to the Raman of solid indicating a lack of chemical interaction to the surface. This result differs to those reported for the SERS of MEH-PPV deposited on gold electrodes in which a new band at 854 cm −1 and a decrease in the relative intensity of the bands at about 1300 and 1580 cm −1 are observed [23]. The difference between the results indicates that polymer processing, that is, spin coating deposition or adsorption form solution phase and/or the 3 Journal of Spectroscopy nature of gold surface (thermal evaporated gold films or citrate-stabilized gold nanoparticles) play an important role on the structure of MEH-PPV on the metal surface.…”

“…These spectra are similar to the spectrum of solid MEH-PPV (Figure 2) showing minimal structural variation from the bulk. This is in agreement to the behavior of MEH-PPV deposited on silver electrodes probed by SERS in which no significant spectral variations were observed under excitation at 785 and 532 nm [23]. Fluorescence background is present in the SERS spectrum at 1 × 10 −4 mol L −1 and it is not observed for the more diluted one.…”

“…Theoretical and experimental vibrational studies of PPV and its oligomers are well reported in the literature describing the structure and the modifications in the neutral and conducting states (n-doped and p-doped) [18][19][20][21][22]. This vibrational characterization has been extended to the PPVbased polymers such as the MEH-PPV, since the polymer backbones are similar [23][24][25][26].…”

“…The interface between polymer and electrode comprising MEH-PPV and thermal evaporated gold or silver was investigated by SERS, showing significant differences between the SERS spectra on these metals assigned to different conformations of MEH-PPV chains [23]. SERS spectra of individual chromophores on single MEH-PPV chains were reported showing two different configurations of the chromophores associated to the packed and loose conformation of the polymer backbone [28].…”

Molecular level studies of polymer behaviors at the water interface using sum frequency generation vibrational spectroscopy

“…28,29 Surface-enhanced Raman spectroscopy is capable of providing highly sensitive surface information of monolayer materials but a specially prepared metal surface is required. [30][31][32] In addition, X-ray photoelectron spectroscopy (XPS) is a powerful technique used to obtain chemical bonding information on polymer surfaces and freeze-dry XPS can be used to study atomic level changes due to water exposure. However, both XPS techniques require ultra-high vacuum.…”