Nonradiative quenching of fluorescence in a semiconducting carbon nanotube:: A time-domain ab initio study

As shown experimentally, strong nonradiative decay channels exist in carbon nanotubes (CNT) and are responsible for low fluorescence yields. The decay of the electronic excitation to its ground state is simulated in the (6,4) semiconducting CNT with surface hopping in the Kohn-Sham representation, providing a unique time-domain atomistic description of fluorescence quenching. The decay in the ideal CNT is estimated to occur on a 150 ps time scale and is only weakly dependent on temperature. Vibrationally induced decoherence strongly influences the electronic relaxation. Defects decrease the excited state lifetime to tens of picoseconds, rationalizing the multiple decay time scales seen in experiments.