Ultrafast Vibrational Energy Transfer from Photoexcited Carbon Nanotubes to Proteins

Abstract

Carbon nanotube (CNT) and protein complexes are one of the most important nanomaterials in physical and biological fields, especially for building biomedical systems based on their unique electronic and optical properties. However, there is little knowledge about ultrafast vibrational phenomena and energy flow in CNT-protein complexes. Here, we study the ultrafast vibrational energy transfer (VET) from photoexcited carbon nanotubes to adsorbed materials, such as protein and surfactant, by observing relaxation dynamics of coherent radial breathing modes (RBMs) of CNT. As a result, we found the vibrational relaxation time of the RBMs depends on phonon density of states (PDOS) of adsorbed materials. Our findings are particularly useful for designing a highly efficient phonon energy flow system from photo-excited CNT to biomaterials, and such vibrational energy transfer can be controlled by the PDOS originated from the structure of coupled biomaterials.