Development of large-scale colloidal crystallisation methods for the production of photonic crystals

McGrath, Joseph

Development of large-scale colloidal crystallisation methods for the production of photonic crystals

dc.check.embargoformat	Not applicable	en
dc.check.info	No embargo required	en
dc.check.opt-out	Not applicable	en
dc.check.reason	No embargo required	en
dc.check.type	No Embargo Required
dc.contributor.advisor	Pemble, Martyn E.	en
dc.contributor.author	McGrath, Joseph
dc.contributor.funder	Science Foundation Ireland	en
dc.contributor.funder	Higher Education Authority	en
dc.date.accessioned	2015-10-23T11:22:51Z
dc.date.available	2015-10-23T11:22:51Z
dc.date.issued	2014
dc.date.submitted	2014
dc.description.abstract	Colloidal photonic crystals have potential light manipulation applications including; fabrication of efficient lasers and LEDs, improved optical sensors and interconnects, and improving photovoltaic efficiencies. One road-block of colloidal selfassembly is their inherent defects; however, they can be manufactured cost effectively into large area films compared to micro-fabrication methods. This thesis investigates production of ‘large-area’ colloidal photonic crystals by sonication, under oil co-crystallization and controlled evaporation, with a view to reducing cracking and other defects. A simple monotonic Stöber particle synthesis method was developed producing silica particles in the range of 80 to 600nm in a single step. An analytical method assesses the quality of surface particle ordering in a semiquantitative manner was developed. Using fast Fourier transform (FFT) spot intensities, a grey scale symmetry area method, has been used to quantify the FFT profiles. Adding ultrasonic vibrations during film formation demonstrated large areas could be assembled rapidly, however film ordering suffered as a result. Under oil cocrystallisation results in the particles being bound together during film formation. While having potential to form large areas, it requires further refinement to be established as a production technique. Achieving high quality photonic crystals bonded with low concentrations (<5%) of polymeric adhesives while maintaining refractive index contrast, proved difficult and degraded the film’s uniformity. A controlled evaporation method, using a mixed solvent suspension, represents the most promising method to produce high quality films over large areas, 75mm x 25mm. During this mixed solvent approach, the film is kept in the wet state longer, thus reducing cracks developing during the drying stage. These films are crack-free up to a critical thickness, and show very large domains, which are visible in low magnification SEM images as Moiré fringe patterns. Higher magnification reveals separation between alternate fringe patterns are domain boundaries between individual crystalline growth fronts.	en
dc.description.sponsorship	Science Foundation Ireland (SFI PI Grant 07/NI.1/I787); Higher Education Authority (PRTLI Project INSPIRE)	en
dc.description.status	Not peer reviewed	en
dc.description.version	Accepted Version
dc.format.mimetype	application/pdf	en
dc.identifier.citation	McGrath, J. 2014. Development of large-scale colloidal crystallisation methods for the production of photonic crystals. PhD Thesis, University College Cork.	en
dc.identifier.endpage	242
dc.identifier.uri	https://hdl.handle.net/10468/2010
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.rights	© 2014, Joseph McGrath	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/	en
dc.subject	Stober synthesis	en
dc.subject	Colloidal photonic crystals	en
dc.subject	Controlled evaporation	en
dc.subject	Production methods	en
dc.thesis.opt-out	false
dc.title	Development of large-scale colloidal crystallisation methods for the production of photonic crystals	en
dc.type	Doctoral thesis	en
dc.type.qualificationlevel	Doctoral	en
dc.type.qualificationname	PhD (Science)	en
ucc.workflow.supervisor	martyn.pemble@tyndall.ie