Carbon nanotubes as emerging near-infrared emitting materials : a route towards their integration in organic light-emitting diodes. (R-11779)

Carbon nanotubes (CNTs) possess uniquely diverse opto-electronic properties that depend critically on their exact diameter and chiral structure. Their 1D structure, high carrier mobility, photochemical and mechanical stability, combined with narrowband, tunable emission in the near-IR, makes them interesting candidates as active materials in organic light-emitting diodes (OLEDs). In this project, we will investigate the ability to functionalise the inner core (encapsulation) and external walls (covalently or non-covalently), providing several degrees of freedom to enhance the CNTs' intrinsic emission quantum yield. Localisation of excitons and triplet sensitization will be studied by optical and electromagnetic resonance spectroscopy. Functionalised CNTs will be integrated in OLEDs through solution processing such as ultrasonic spray coating (USSC). The influence of the CNTs' work function will be studied to perform an appropriate material selection for OLED construction. Further, the effect of CNT alignment in the active layer will be researched (slow evaporation during USSC, plasma poling or vacuum filtration) to enhance the outcoupling efficiency of OLEDs. This project will capitalize on the expertise of two groups in (i) CNT optical characterization, sorting and functionalization and (ii) OLED design and fabrication, and will provide a fundamental understanding of the mechanisms influencing CNT emission, as such paving the way to the CNTs' long awaited applications.

Keywords:carbon nanotubes, organic light emitting diodes

Disciplines:Optical properties and interactions with radiation, Spectroscopic methods, Semiconductor devices, nanoelectronics and technology, Nanomaterials, Functionalisation of materials