Final Report Summary - EN-LUMINATE (Enhancing and Tuning Electroluminescence with Nanoantennas)
Control over light-matter interaction is one of the major research themes of this decade. Being able to enhance and tune the interaction of a light wave with a molecule or material opens up exciting applications. The near-infrared (800 – 1800 nm) is of particular interest due to its importance for bio-imaging and telecommunication and the lack of good molecular emitters in this wavelength range. Here, we applied metallic nanostructures as antennas to concentrate the electromagnetic field of light and consequently changed the properties of the emitters. We integrated plasmonic nanoantennas in light-emitting field-effect transistors with semiconducting polymers and purified single–walled carbon nanotube that exhibit fast charge transport and emit light in the near infrared to improve and tune their electroluminescence. By applying plasmonic crystals of periodic nanodisk arrays fabricated by top-down electron-beam lithography and random nanorod films produced by bottom-up colloidal synthesis we enhanced the outcoupling efficiency of the emitted photons, increased the radiative decay of the excited states and consequently improved emission efficiency but also changed the emission wavelength and directionality. We further used near-infrared emitting semiconducting polymers and semiconducting single–walled carbon nanotube in cavity-integrated light-emitting field-effect transistors to demonstrate optically and electrically pumped exciton-polariton formation (i.e. new quasiparticles resulting from the hybridization of light and matter) via strong coupling and thus fundamentally changed the emission properties of these materials. Thanks to the accompanying optimized purification of materials, improved processing of devices and enhanced understanding of charge transport and electroluminescence in thin films of semiconducting polymers and carbon nanotubes we reached current and hence polariton densities that are promising for future electrically pumped polariton lasing at room temperature.