Brightening of excitons in carbon nanotubes on dimensionality modification

Abstract

Despite the attractive one-dimensional characteristics of carbon nanotubes, their typically low luminescence quantum yield, restricted because of their one-dimensional nature, has limited the performance of nanotube-based light-emitting devices. Here, we report the striking brightening of excitons (bound electron–hole pairs) in carbon nanotubes through an artificial modification of their effective dimensionality from one dimension to zero dimensions. Exciton dynamics in carbon nanotubes with luminescent, local zero-dimension-like states generated by oxygen doping were studied as model systems. We found that the luminescence quantum yield of the excitons confined in the zero-dimension-like states can be more than at least one order larger (~18%) than that of the intrinsic one-dimensional excitons (typically ~1%), not only because of the reduced non-radiative decay pathways but also due to an enhanced radiative recombination probability beyond that of intrinsic one-dimensional excitons. Our findings are extendable to the realization of future nanoscale photonic devices including a near-infrared single-photon emitter operable at room temperature.