Mitchell D. Anderson, Yee-fang Xiao, James M. Fraser
The quantum yield of semiconducting single walled carbon nanotubes is limited by strong diffusion driven end/defect quenching and rapid Auger-like exciton-exciton annihilation (EEA) processes. While these two processes have been extensively studied independently, we show that both effects must be considered to properly extract intrinsic nanotube properties. To achieve this result, we have developed a convenient analytic model of exciton dynamics (verified by comparison to Monte Carlo simulations) that shows the intrinsic optical quantum efficiency is substantially higher than previously reported from observations in typical samples. Diffusion limited EEA is modeled using a one dimensional line segment revealing enhanced annihilation at low exciton populations. Lastly, the analytic model is demonstrated using nonlinear EEA effects to extract intrinsic absorption cross sections, lifetimes, and diffusion lengths for SWCNTs.
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http://arxiv.org/abs/1207.1285
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