Multistep Wavelength Switching of Near-Infrared Photoluminescence Driven by Chemical Reactions at Local Doped Sites of Single-Walled Carbon Nanotubes.

Local chemical functionalization is used for defect doping of single-walled carbon nanotubes (SWNTs), to develop near-infrared photoluminescence (NIR PL) properties. We report the multistep wavelength shifting of the NIR PL of SWNTs through chemical reactions at local doped sites tethered to an arylaldehyde group. The PL wavelength of the doped SWNTs is modulated based on imine chemistry. This involves the imine formation of aldehyde groups with added arylamines, imine dissociation reaction, exchange reaction of bound arylamines in the imine, and the Kabachnik-Fields reaction of imine groups using diisopropyl phosphite. Using doped sites as a localized chemical reaction platform can exploit the versatile molecularly driven functionality of carbon nanotubes and related nanomaterials.

Control of the Near Infrared Photoluminescence of Locally Functionalized Single-Walled Carbon Nanotubes via Doping by Azacrown-Ether Modification.

Doped semiconducting single-walled carbon nanotubes (SWNTs) through local chemical functionalization (lf-SWNTs) show fascinating photoluminescence (PL) that appears with a longer wavelength and enhanced quantum yield compared to the original PL of non-modified SWNTs. In this study, we introduce an azacrown ether moiety at the doped sites of lf-SWNTs (CR-lf-SWNTs), and observe selective PL wavelength shifts depending on different interaction modes of silver ion inclusion and protonation of the amino group in the ring. Interestingly, their different values of the wavelength shifts show a clear correlation with calculated electron density of the nitrogen atom in the azacrown moiety in case of the inclusion form and the protonated form. This newly-observed responsiveness based on molecular interactions is expected to create doped sites that can versatilely control the PL functions based on molecular systems.

Near infrared photoluminescence modulation by defect site design using aryl isomers in locally functionalized single-walled carbon nanotubes.

We newly introduce positional isomeric structures at the defect sites of locally-functionalized single-walled carbon nanotubes (lf-SWNTs) showing unique near infrared photoluminescence (PL). The observed PL is significantly different from that of typical para-aryl modified lf-SWNTs; i.e., (i) an extraordinary PL wavelength shift of the meta-aryl modified lf-SWNTs, and (ii) remarkably red-shifted PL from the ortho-aryl modified lf-SWNTs are revealed.

Near infrared photoluminescence modulation of single-walled carbon nanotubes based on a molecular recognition approach.

We present a concept to modulate near infrared photoluminescence (NIR-PL) from locally-functionalized single-walled carbon nanotubes (local-f-SWNTs) based on a molecular recognition approach using newly synthesized phenylboronic acid (PB)-functionalized local-f-SWNTs (PB-SWNTs) and saccharides, in which a selective PL spectral shift is observed by addition of the saccharides.