Encapsulation effect of π‐conjugated quaterthiophene on the radial breathing and tangential modes of semiconducting and metallic single‐walled carbon nanotubes

Abstract

We developed a hybrid approach, combining the density functional theory, molecular mechanics, bond polarizability model and the spectral moment's method to compute the nonresonant Raman spectra of a single quaterthiophene (4T) molecule encapsulated into a single-walled carbon nanotube (metallic or semiconducting). We reported the optimal tube diameter allowing the 4T encapsulation. The influence of the encapsulation on the Raman modes of the 4T molecule and those of the nanotube (radial breathing modes and tangential modes) are analyzed. An eventual charge transfer between the 4T oligomer and the nanotube is discussed.

Charge transfer evidence in donor–acceptor single‐walled carbon nanotubes filled with sexithiophene oligomers: Nanotube diameter dependence

“…The splitting of the G − and G + Raman peaks (two narrow Lorentzian peaks), and their assignment to the TO and LO phonons, respectively, was discussed in our previous work. [ 32 ]…”

“…Calculation of Raman spectra necessitates the knowledge of the dynamical matrix (DM) and the polarizability tensor of the system. In our previous works , [ 32,33 ] we developed a hybrid approach to compute the nonresonant Raman spectra of bi‐thiophene (2T) and quater‐thiophene (4T) molecules encapsulated into metallic and semiconducting SWNTs, combining the density functional theory (DFT), molecular mechanics, bond polarizability model, and SMM. The DM of the hybrid system has a 3 N × 3 N dimension ( N is the number of atoms in the primitive unit cell).…”

“…In order to complete our study about the encapsulation of a series of oligothiophenes in SWNTs, [ 32,33 ] we propose here a comparative investigation on the structural and vibrational properties of nanohybrids formed through SWNTs filled with one of the most important classes of conjugated oligomers that can be applied as photoactive material in OSCs, sexithiophene (6T). [ 34,35 ] It is well known that SWNTs behave not only as electron acceptors but as light‐harvesting electron donors as well depending on the electronic nature of the molecule used for their functionalization.…”

Role of carbon nanotubes as an acceptor to enhance the photovoltaic performances of organic solar cells based on π ‐conjugated thiophene as a donor materials

“…For an adequate description of these long‐ranged dispersive forces, the structure relaxation is performed by minimizing the distance between atoms associated with LJ potential. In previous works, 33,34 we represented the LJ potential for 2T@SWNT and 4T@SWNT as a function of SWNT diameter. Here, to make a comparison between the different hybrids, we present in Figure 1 the LJ potential as a function of SWNT diameter varying from 0.8 to 2.7 nm for nT@SWNTs hybrid systems.…”

“…Calculation of Raman spectra necessitates the knowledge of the dynamical matrix (DM) and the polarizability tensor of the system. In our previous works, 33,34 we devolved a hybrid approach to compute the nonresonant Raman spectra of bithiophene (2 T) and quaterthiophene (4 T) molecules encapsulated into metallic and semiconducting SWNTs, combining the DFT, molecular mechanics, bond polarizability model and SMM. The DM of the nT@SWNTs hybrids is built block by block from the DM of each subsystem: the DM of the SWNT and oligothiophene molecules nT forms the bidiagonal block of the DM of the nT@SWNTs, while the DM associated with the nT and SWNT interactions forms the off‐diagonal block.…”