Ultrafast Vibrational Energy Transfer from Photoexcited Carbon Nanotubes to Proteins

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.

Green Synthesis and Radial Breathing Modes inTiNanoparticles

This work presents the synthesis of metallic nanoparticles of titanium. The extract from the nopal (Opuntia ficus-indica) plant was used as the redactor agent. The results of transmission electronic microscopy (TEM) show that nanoparticles have a sphere-like shape with an approximate diameter of 1–4 nm. The presence of Ti in these particles was corroborated by energy dispersive X-ray spectroscopy (EDS). Optical properties were detected with the presence of absorption bands centered in 295 nm and 355 nm, similar to those reported in the literature. Two Raman bands centered at 359 cm-1and 404 cm-1were observed after the synthesis of titanium nanoparticles. Afterwards, structural and vibrational parameters of small clusters of Ti ( Tin, n = 3–13) were analyzed by the density functional theory (DFT) at the B3LYP level of approximation combined with the basis set LANL2DZ. Radial breathing modes (RBMs) were detected in the vibrational spectrum of each cluster, placed around 298–387 cm-1.