Near infrared photoluminescence (NIR PL) of semiconducting single-walled carbon nanotubes (SWNTs) is a unique feature based on the one-dimensional nanostructures. Recently, a very limited amount of chemical modification of SWNTs is reported to enhance NIR PL properties, in which oxygen atom doping as well as sp³defect doping are applied to the π-conjugated networks of the SWNT walls. As a result, quantum yield increment and emission wavelength shifts were observed.[1-3] Thus, the locally-functionalized SWNTs (local-f-SWNTs) are expected as novel NIR PL materials because quantum yields of pristine SWNTs are typically low and the tube structures defined by chiral indices determine emission wavelengths.

In this study, we utilize the PL of local-f-SWNTs to read out differences of molecular structures that are constructed at the modified sites by covalent or noncovalent approaches.[4,5] For example, a phenylboronic acid-modified local-f-SWNTs show PL wavelength shifting by attachment of saccharide molecules through molecular recognition at the modified sites, as shown in Figure.[5]

Thus, the present system would be applicable to a novel detection technique that converts molecular information to NIR PL towards future applications including bio-imaging/sensing.

References: [1] Weisman, R. B. et al., Science 2010, 330, 1656-1659. [2] Wang, Y. et al., Nat. Chem. 2013, 5, 840-845. [3] Nakashima, N. et al., J. Phys. Chem. C 2016, 120, 15632-15639. [4] Nakashima, N. et al., Sci. Rep. 2016, 6, 28393. [5] Nakashima, N. et al., Chem. Commun. 2016, 52, 12972-12975.