(Invited) Photoluminescence Carrier Dynamics and Photon Statistics of Covalent Dopant-Induced Trap States in Single Wall Carbon Nanotubes

Recent advances in low level covalent functionalization of carbon nanotubes are receiving significant attention due to new emitting states being introduced by chemically stable oxygen^1,2 and aryl diazonium dopants³ that increase photoluminescence quantum yields.  Recent low-temperature studies have further elucidated the associated chemical and electronic structure.⁴  We report here photoluminescence studies of dynamic behaviors of the dopant sites.  Relevant to their potential uses in imaging and as novel photon sources, we demonstrate blinking behaviors and discuss a range of response as a function of dopant species.  We also report across a range of dopants photoluminescence decay dynamics obtained at the ensemble and single tube levels.  We find that localization of excitons at dopant sites dramatically increases photoluminescence lifetimes, indicating the importance of exciton trapping as a route to limiting non-radiative decay pathways arising from exciton mobility.  Relevant to interest in these new emitting states as single photon emitters for quantum information processing, we also demonstrate an approach to stabilizing emission output while also introducing solitary dopant sites.  Finally, lifetime and photon correlation studies enabled by superconducting nanowire single-photon detectors will be presented.  Evolution of behaviors as a function of temperature will be discussed in the context of realizing room-temperature photon antibunching.

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4.  X. Ma, et al., ACS Nano, 8, 10782 (2014).