Background
Over the past decade there has been enormous interest in the development of mechanochromic photonics crystals as visual sensors. There are typically three ways to produce colour; pigmentation, emission or structural colour. Mechanchromic structures explit structural colour resulting from the interference of light. A general term of structues that can be used to manipulate colour in this way is photonic crystals. The reflected or transmitted colour depends on the materials and structure. The structures can be as simple of planar thin films or as complex as the features in the blue morpho butterfly wings or 3D opal crystals. Many structures are inspired by those occurring in nature. Mechanochromic structures use materials which swell in response to a stimulus (liquid, gas, chemical) or which can be stretched or compressed with a resulting changing in the observed colour. The extent of the extent of the colour change, the sensitivity to the stimulus and the response time are all critical parameters that must be considered depending on the specific application. Often the structures
fabricated to date are relatively simple, such as multi-planar layers or a grating on a surface, and the range of colour tuning is quite limited.

Innovation
The innovation in this project is that we will investigate structures that can be fabricated via direct laser writing using two photon polymerization.

Collaboration
This project is in collaboration with Prof. Larisa Florea in the School of Chemistry. As it is a collaborative project it will offer lots of opportunity for discussion with the material scientists so that we can understand and balance what is possible from a materials perspective with what is required from a photonics perspective to achieve the optimal sensor response. Our contribution to the project is in the structure design, materials characterization, optical characterization of the laser printed structures and simulation of experimental results to understand the material changes and how the sensors can be further optimized. The project is also in collaboration with Dr. Radislav Potyrailo, General Electric Research, USA.

Objectives and methodology
The objective of the objective of this project will be to develop solution based chemical sensors

For further details please see:

https://www.tcd.ie/Physics/study/prospective/postgraduate/