Trion photoluminescence of covalently functionalized single-walled carbon nanotubes

A.H. Brozena, J.D. Leeds, Y. Zhang, J. Huang, A. Ng, Y.H. Wang
University of Maryland, US

Keywords: carbon nanotubes, trion, photoluminescence, defects


Covalent functionalization is thought to completely destroy many optical properties of single-walled carbon nanotubes (SWNTs), particularly photoluminescence, due to the introduction of sp3 defects to the sp2 carbon lattice. However, recent studies have shown that when functionalized to a low degree, not only is bandgap photoluminescence retained to a great extent, but new optical features may also be introduced. Here, we study one of these new features: SWNT trion fluorescence. Covalent functionalization with the simultaneous use of highly reductive conditions generates SWNT trion photoluminescence by localized doping at introduced sp3 defects. This is the first evidence of SWNT trion emission as a result of highly controlled, covalent chemistry and furthermore shows that SWNT trion fluorescence can be stable under ambient conditions due to the ability of sp3 defects to trap and stabilize the excess carrier population which enables charged excitons to form.