Exciton dynamics and energies in single carbon nanotubes

点击翻译按钮获取中文摘要

Based on their exceptional optical properties, carbon nanotubes play an important role as nanometer-scale building-blocks for optoelectronics, nanoelectronics and biosensing. Optical excitation of nanotubes generates excitons that determine all light-based applications. We propose to study excitons in nanotubes on ultrafast timescales using a novel type of interferometric white-light scattering microscopy that provides ultimate detection sensitivity. First, the optical response of single nanotubes, a fingerprint of the nanotube structure, is determined quantitatively by detecting Rayleigh scattering spectra. Scattering spectra taken at different time delays after pulsed excitation then reveal energies and population dynamics of photo-generated states. We determine the correlation between the exciton decay and the nanotube structure for a broad diameter range for first the time and study energy transfer interactions between nanotubes within single bundles of known composition. Our results will allow us to identify different nonradiative decay channels that limit the widespread use of nanotubes in optical devices. In addition, our work will contribute to the development of the novel microscopy technique that is expected to have a major impact on the field of ultrafast processes in single nanoscale systems