Intermolecular vibrational energy transfer between SWCNTs with different chiralities

Ultrafast spectroscopy was performed for two kinds of SWCNT samples; a sample purified to have a single chirality (purified) and one containing variety of chiralities (non-purified). There are three relaxation processes with corresponding rates which were estimated as 10ps-1,2ps-1,and0.5ps-1. The fastest rate is attributed to intraband relaxation in the electronic excited state, and the other two are for parallel relaxation process of interband relaxation to the electronic ground state. Vibrational frequency of radial breathing mode was found to show up-shift only in the non-purified sample (not in the purified one), which indicates intermolecular vibrational energy transfer between SWCNTs with different chiralities from each other.