Mr Ben Hogan
PhD Project2D liquid crystal composites for integrated optoelectronic devices
Supervisors: Dr. Anna Baldycheva & Dr. Monica Craciun
The liquid crystal phase has been known and studied for over 100 years (Figure 1) with a wide range of modern-day applications- most notably being ubiquitous in displays. But where else could they find applications? My current research work is focussed on the development of novel liquid crystalline composites incorporating two-dimensional materials (graphene etc.) for applications in optoelectronics and photonics [Hogan et al., 2D Material Liquid Crystals for Optoelectronics and Photonics, J. Mater. Chem. C, 2017]. By utilising the reconfigurability of the orientation of the liquid crystal mesogens under applied fields (electric, magnetic, thermal…) we propose that 'metastructuring' can be achieved. That is, two-dimensional nanoparticles dispersed within a liquid crystalline host can be controllably positioned to form metamaterial structures. We have shown that liquid crystalline composites with dispersed two-dimensional material nanoparticles can be readily synthesised and integrated into CMOS-compatible microfluidic systems [Hogan et al., Dynamic in-situ sensing of fluid-dispersed 2D materials integrated on microfluidic Si chip, Scientific Reports, 2017]. As part of this work, we developed a novel characterisation method, using Raman spectroscopy to elucidate the positions of nanoparticles within microfluidic structures. In the (near) future, this novel methodology will allow us to monitor the spatio-temporal evolution of metastructure formation under applied fields. We are also working on applying 2D materials in devices such as optoelectronic modulators across a range of wavelength ranges, sensors and detectors for several analyte paradigms, laser pulse generation and other exciting emerging fields.
Figure 1: Timeline of the history of liquid crystal phase applications, from their discovery to the present day.