CarBon nanotube exohedral and endohedral functionalization for integration in neaR-Infrared organic liGHT emitting devices

Single-walled carbon nanotubes (SWCNTs) possess uniquely diverse optoelectronic properties that depend critically on their exact diameter and chiral structure.

Their quasi one-dimensional structure, high carrier mobility, photochemical and mechanical stability, combined with extremely narrow and tunable emission in the near-infrared (NIR), make them interesting candidates as active material in NIR organic light-emitting diodes (OLEDs) or light-emitting transistors (LETs).

The integration of SWCNTs in OLEDs and LETs has so far been limited by their typically low intrinsic emission quantum efficiency.

Enhancing the SWCNTs emission efficiency, therefore, requires an in-depth understanding of the complex exciton photophysics, in particular, that of the multiple dark excitons.

In this project, we will investigate the filling of the SWCNTs inner hollow core combined with functionalizing their outer wall with particular triplet sensitizers.

This provides two orthogonal degrees of freedom to enhance intersystem crossing to the triplet state and at the same time to make the triplet excitons bright, aiming for highly efficient SWCNTs triplet phosphorescence as a NIR emission source.

To investigate the particular effect of the functionalization on the triplet exciton photophysics, we will make use of a unique technique that combines optical spectroscopy with the spin-selective magnetic resonance technique, namely optically-detected magnetic resonance (ODMR). Finally, as a proof-of-principle, these functionalized SWCNTs will be integrated in LETs and OLEDs.

In operando characterization through, amongst others, electrically-detected magnetic resonance (EDMR) will be performed to determine the role of the spin-dependent electron-hole recombination processes in the devices, opening new avenues to highly emissive NIR-OLEDs/LETs, essential for a wide range of biomedical and biosensing applications.