<i>Meta</i>-linkage Design of Bis-aryldiazonium Modifiers for Wavelength Tuning of Near Infrared Photoluminescence from Locally Functionalized Single-walled Carbon Nanotubes

Abstract

Local chemical functionalization of single-walled carbon nanotubes has been reported to modulate their near infrared photoluminescence (PL), where defect doping creates new emissive sites on the nanotubes. Previously, we reported on proximal defect doping with the use of bis-aryldiazonium salts, which considerably red-shifted nanotube PL (>1200 nm). In this study, we achieved PL modulation with newly designed bis-aryldiazonium modifiers having meta-linked methylene spacers. The spacer length-dependent wavelength shifts were greater than those of our previous para-linkage design. Bis-aryl modification of single walled carbon nanotubes with semiconducting features provides near infrared photoluminescence over 1200 nm, in which proximal defect doping occurs to their sp2 carbon network structures. Meta-linkage design in the synthesized modifiers allows wavelength modulation in wider wavelength ranges depending on the methylene linker lengths compared to para-linkage one.