Imprinted Photonic Crystal Chemical Sensors

In this paper we present the use of Photonic Crystals as chemical sensors. These 2D nanostructured sensors were prepared by nano-imprint lithography during which a nanostructure is transferred from a nickel template into a responsive polymer, that is be specifically tuned to interact with the chemical compound that must be detected. By creating a Photonic Crystal in a responsive polymer, the sensitivity of such a sensor can be greatly enhanced with respect to nanophotonic sensors that are only functionalized by a surface treatment. We have shown the functionality of an imprinted sensor by exposing the nanostructures to various liquids and vapours and monitor the change in reflected signal. Depending on the interactions and refractive index contrasts, the maximum wavelength of the reflected light can decrease (when exposed to toluene) or increase (when exposed to acetone).