The study of hybrid systems MPA@SWNT of peapods kind involving photoactive molecules (MPA) confined in single-walled carbon nanotubes (SWNT) find its motivation in the possibility of modulating the physical properties of the nanotubes. Many experimental studies using vibrational spectroscopy in particular are interested in the physical properties of these hybrid systems. The key point of this issue is the nature of the interaction between the nanoconfinement matrix and MPAs, and the complexity of its study requires a comparison between experimental data and modelizations. In this work, we study the hybrid systems MPA@SWNT through modeling performed in different settings ranging from the use of molecular dynamics (MD) to that of the density functional theory (DFT). The limiting factor in DFT calculations is the computation time. the latter which varies in N3 (N is the number of atoms) increases drastically when N exceeds a hundred atoms for energy minimizations calculation, and even more for phonons calculations. In this context, the study of hybrid systems with organic MPAs is delicate. Indeed, the MPAs are complex molecules generally comprising side chains for the solubility of the system. For example, the smallest hybrid system studied, which consists on encapsulating a single molecule of thiophene oligomer functionalized with methyl groups at the edges inside an (11,0) nanotube contains 344 atoms. For the computation time not to be prohibitive, we tested different methods of simulation of the vibrational spectra of MPA@SWCNT: molecular dynamics, tight binding, and hybrid calculations MD/DFT. We discuss in details the results comparing models with experimental data for 1D thiophene oligomer molecules encapsulated inside nanotubes.

The structural properties of Agy(Ge0.25Se0.75)1-y thin films (y=0, 0.07, 0.10, 0.15, 0.20 and 0.25 at. fraction) were studied. The films were prepared by pulsed laser deposition using bulk glass targets of the studied ternary system and deposited onto microscope slides. Their amorphous structures were confirmed by XRD (X-ray Diffraction). The effect of silver content on films structures was analysed by Raman spectroscopy. Typical Raman vibration modes were observed in the Ge0.25Se0.75 binary film: Ge-Se corner-sharing tetrahedra mode (CS) at 199 cm-1, edge sharing tetrahedra mode (ES) at 217 cm-1, and Se-Se rings and chains mode at 255-265 cm-1 (CM). In the Agy(Ge0.25Se0.75)1-y ternary thin films, the same modes were observed but with a red shift and an intensity reduction in the ES and CM bands.

Photo-active molecules are confined into single-wall carbon nanotubes to create 1D hybrid systems with new and original opto-electronic properties. This work deals with the encapsulation of quaterthiophene derivative and phthalocyanine molecules. They display strong optical absorption in the visible range, respectively around 400 and 670 nm. Encapsulation efficiency is investigated through Transmission Electron Microscopy. The physical interactions are mainly investigated by optical spectroscopies. The Raman spectra of the oligothiophene hybrid systems exhibit a striking dependence with the excitation energy which is correlated to the optical absorption energy of the photo-active molecule. Close to the molecule resonance, the results suggest a significant photo-induced charge transfer between the photo-active molecules and the nanotubes. In addition, the resonance window of the confined molecules depends on the nanotube diameter. The Raman spectra of the phthalocyanine based systems depend on the optical resonance conditions of the encapsulated molecules and on the structural properties of the hybrid system.

Agx(Ge0.25Se0.75)100 x glasses with x varying from 0 to 25 have been shown to exhibit a conductivity threshold around x ~8-10. In this work, the structural changes induced by introduction of Ag in Ge25Se75 glass have been investigated using Raman and infra-red spectroscopies. In ambient conditions, changes are observed in position, width and intensity for vibrations assigned to Ge-Se bonds, showing that the tetrahedral network is relaxed and gains flexibility as Ag is introduced. High pressure experiments on two glasses containing 5 and 25 at.% Ag confirm that Ag-rich (25%) glasses clearly exhibit higher compressibility than Ag-poor (5%) glasses.

Vibrational dynamics in the corannulene crystal is exhaustively studied through Raman scattering, infrared spectroscopy, and inelastic neutron scattering. Experimental data are coupled to simulations of the phonon modes performed in the framework of first principle calculations. Intermolecular vibrations (libration and translation) are assigned in the low frequency domain (10-200 cm-1). These modes exhibit specific temperature dependence in the far-infrared.

This study deals with a hybrid system consisting in quaterthiophene derivative encapsulated inside single-walled and multi-walled carbon nanotubes. Investigations of the encapsulation step are performed by transmission electron microscopy. Raman spectroscopy data point out different behaviors depending on the laser excitation energy with respect to the optical absorption of quaterthiophene. At low excitation energy (far from the oligomer resonance window) there is no significant modification of the Raman spectra before and after encapsulation. By contrast, at high excitation energy (close to the oligomer resonance window), Raman spectra exhibit a G-band shift together with an important RBM intensity loss, suggesting a significant charge transfer between the inserted molecule and the host nanotubes. Those results suggest a photo induced process leading to a significant charge transfer.