posted on 2019-08-27, 20:14authored byMerve Balcı Leinen, Felix J. Berger, Patrick Klein, Markus Mühlinghaus, Nicolas F. Zorn, Simon Settele, Sybille Allard, Ullrich Scherf, Jana Zaumseil
Conjugated
polymers exhibit strong interactions with single-walled
carbon nanotubes (SWNTs). These enable the selective dispersion of
specific semiconducting SWNTs in organic solvents and polymer-mediated
energy transfer to the nanotubes followed by emission in the near-infrared.
Conjugated polyelectrolytes with ionic side-chains can add further
functionalities to these nanotube/polymer hybrids such as dispersibility
in polar solvents (e.g., methanol) and self-doping. Here, we demonstrate
and investigate energy transfer from a range of conjugated polymers
to preselected (6,5) SWNTs with varying spectral overlap between the
optical transitions of the polymer and nanotube. We find evidence
for increased backbone planarization of the polymers wrapped around
the nanotubes. Furthermore, ambient p-doping of hybrids of anionic
conjugated polyelectrolytes and (6,5) SWNTs blocks energy transfer
in contrast to cationic polyelectrolytes. By addition of a mild reducing
agent, thus removing the p-doping, the energy transfer can be fully
restored pointing toward an electron exchange mechanism. The p-doping
of nanotube/polyelectrolyte hybrids in air and their doping-dependent
emission and charge transport properties also become apparent in water-gated
field-effect transistors based on such networks and might be useful
for dual-signal sensing applications.