Solution-processed nanostructures and devices for highly polarized light generation, scattering and sending

Abstract

Recent advancements in photonics have facilitated robust and reliable light sources, displays and photosensors with relatively long lifetimes and high energy efficiency in their classes. However, developing intrinsically polarization selective photonic devices still remains a challenge, although polarization sensitivity is essential to various advanced functions and/or improved performance. One of the main difficulties in making such devices emerges from the compromise on the efficiency while striving to reach high polarization contrast levels. For instance, commercially available birefringent structures including those integrating liquid crystals suffer from major transmission losses. On the other hand, solutionprocessed, high aspect-ratio nanostructures may offer power efficient platforms with high polarization contrasts via selection of the polarization in a preferred direction during emission, absorption and/or scattering process(es) while suppressing efficiency of the relevant ones in the other polarization. In this thesis, we present solution-processed metal and semiconductor nanostructures and optoelectronic devices made from them for highly polarized light generation and enhanced photosensing. Here we developed and demonstrated in-template fabricated suspended arrays of plasmonic thin nanodiscs with tunable disc-heights and gap-widths tailoring absorption and scattering properties for applications ranging from polarized light scattering to photodetection. Also, we proposed and showed highly polarized light emission in coupled thin films of magnetically aligned multisegmented nanowires and colloidal nanocrystals for polarized color enrichment in displays. Here well-controlled in-template synthesis of these nanowires together with their alignment under magnetic field allows for highly parallel orientation of the nanowires in massive numbers over large-area thin films. Integrating with color-enriching nanocrystals, this enabled a record high polarization contrast over 15:1 for the isotropic nanocrystals in the visible range. We believe that such hybrid assemblies of solution-processed nanostructures integrated into optoelectronic devices hold great promise for advanced functions in photonics.