Trions and sp3-defects in single-walled carbon nanotubes for optoelectronics
Semiconducting single-walled carbon nanotubes (SWNTs) combine solution-processability, large carrier mobilities, narrow emission linewidths and environmental stability for optoelectronic devices with light-emission in the near-infrared (800-1800 nm, e.g., for optical data communication and bio-imaging) when sorted by (n,m) species. The recent availability of highly pure, monochiral semiconducting SWNTs as bulk materials allows us to employ and further tailor their charge transport and light emission properties and thus enables their application in practical devices. Two new emissive species - charged excitons (trions) and bright sp3-defects - were recently discovered in SWNTs and have fundamentally changed our notions about SWNT luminescence. Both show red-shifted, narrow and enhanced emission. However, very little is yet known about their photophysical properties and especially their interactions with each other and their environment (e.g., in devices). Their emissive properties could potentially be tailored by external magnetic fields, dielectric environment and additional functional groups. Strong light-matter coupling in suitable optical cavities could be applied to create trion-polaritons in SWNTs as new low-mass charge carriers in polaritonic devices. Trions and emissive sp3-defects are not limited to SWNTs and hence these concepts could be transferred and applied to other low-dimensional semiconductors. 

The goals of this project are to
-  understand and use trions and trion-polaritons for light emission and polaritonic charge transport,
-  understand and tune the interactions of sp3-defects with charges and trions in SWNTs,
- modify and apply sp3-defects for enhanced light emission from SWNTs in optoelectronic devices,
-  explore trions in new low-dimensional materials (e.g., graphene nanoribbons and novel monolayered semiconductors).