Raman resonance tuning of quaterthiophene in filled carbon nanotubes at high pressures

Filling carbon nanotubes with molecules is a route for the development of electronically modified one-dimensional hybrid structures which interplay between electronic structure and key factor. Tuning these energy levels external parameters an interesting strategy engineering new devices materials. Here we show that system composed by quaterthiophene (4T) confined in single-walled nanotubes, presents piezo-Raman-resonance molecule vibrational pattern. This behavior manifests as rapid pressure induced enhancement 4T Raman mode intensities compared to tubes G-band modes. Density functional theory calculations allow explain spectral behaviour through pressure-enhanced resonance evolution. By increasing pressure, tube cross-section deformation leads reduction intermolecular distance, splitting molecular then increase channels. Calculations experiments converge piezo-resonance scenario associated pressure-induced nanotube radial collapse observed at about 0.8 GPa. Our findings offer possibilities transducers based on molecule-filled nanotubes.