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Remotely Adjustable Structural Plasmonic Colour

Periodic Reporting for period 1 - Smart Colour (Remotely Adjustable Structural Plasmonic Colour)

Reporting period: 2016-07-01 to 2018-06-30

In this project, we developed a tunable plasmonic and non-plasmonic structural colour. The structural colour realized in this project was based on two geometries and materials. The first one was made of arrangement of periodic nano hole arrays perforated to the silicon wafer. It was found that changing the geometry of the holes and their 2D arrangement induces colour change. The second geometry was made of polymeric posts with circular or rectangular shape in which a thin metal layer was was deposited. There, changing the pitch of the polymeric posts, thickness of the metals and size of the posts enables colour adjustability. In contrary to the pigment based colorant, the developed structural colour is robust, non-toxic, durable and ultimately can be used in high resolution printing beyond the capability of ink-base printers. The developed structural colour can be used as a sustainable and environmental friendly alternative for counterfeit application, sub-diffraction optical sensor and decorative coating.
Examples of the results are attached as images to the report.
The overall objective of furthering the fellows career has been fulfilled, since I have been employed as Assistant Professor at Durham University, UK.
The project includes design, fabrication and characterisation of plasmonic and non-plasmonic metasurface structural colour. It comprises development of fabrication method, nano-patterning and optical analysis of 3D nano-patterns of noble metals and semi-conductors. The design was carried out with COMSOL simulation while the experimental part was done in combination of lithography (nano imprint and DUV stepper). The characterisation of the 3D nano-patterns were performed with scanning electron microscopy (to study the morphology), spectroscopy (to analyse the optical response) and optical microscopy (for colour characterisation).
The results of the project has immense potential to be used in colour industry as a cost-effective and up-scalable alternative to pigment base colorant. Since all the materials used are recyclable and mechanically durable, implementation of the concept in the society would reduce the CO2 emission and recycling problems of pigment base colorants. Although the fabrication cost of the structural colour presented in this project is still higher than pigment counterpart, further optimisation in fabrication can make the concept soon as an feasible and affordable replacement for painting industry.