2026-09-21T22:10:04Zhttps://cora.ucc.ie/server/oai/request

oai:cora.ucc.ie:10468/20102023-04-04T07:03:39Zcom_10468_178com_10468_5com_10468_388com_10468_1com_10468_41com_10468_6col_10468_179col_10468_389col_10468_140col_10468_3619

Not applicable No embargo required Not applicable No embargo required No Embargo Required Pemble, Martyn E. McGrath, Joseph Science Foundation Ireland Higher Education Authority 2015-10-23T11:22:51Z 2015-10-23T11:22:51Z 2014 2014 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. Science Foundation Ireland (SFI PI Grant 07/NI.1/I787); Higher Education Authority (PRTLI Project INSPIRE) Not peer reviewed Accepted Version application/pdf McGrath, J. 2014. Development of large-scale colloidal crystallisation methods for the production of photonic crystals. PhD Thesis, University College Cork. 242 https://hdl.handle.net/10468/2010 en University College Cork © 2014, Joseph McGrath http://creativecommons.org/licenses/by-nc-nd/3.0/ Stober synthesis Colloidal photonic crystals Controlled evaporation Production methods false Development of large-scale colloidal crystallisation methods for the production of photonic crystals Doctoral thesis Doctoral PhD (Science) martyn.pemble@tyndall.ieinfo:eu-repo/semantics/openAccess