  The controlled covalent functionalization of semiconducting single-walled
carbon nanotubes (SWCNTs) with luminescent sp$^{3}$ defects leads to additional
narrow and tunable photoluminescence features in the near-infrared and even
enables single-photon emission at room temperature, thus strongly expanding
their application potential. However, the successful integration of
sp$^{3}$-functionalized SWCNTs in optoelectronic devices with efficient defect
state electroluminescence not only requires control over their emission
properties but also a detailed understanding of the impact of functionalization
on their electrical performance, especially in dense networks. Here, we
demonstrate ambipolar, light-emitting field-effect transistors based on
networks of pristine and functionalized polymer-sorted (6,5) SWCNTs. We
investigate the influence of sp$^{3}$ defects on charge transport by employing
electroluminescence and (charge-modulated) photoluminescence spectroscopy
combined with temperature-dependent current-voltage measurements. We find that
sp$^{3}$-functionalized SWCNTs actively participate in charge transport within
the network as mobile carriers efficiently sample the sp$^{3}$ defects, which
act as shallow trap states. While both hole and electron mobilities decrease
with increasing degree of functionalization, the transistors remain fully
operational, showing electroluminescence from the defect states that can be
tuned by the defect density.
