{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/31306"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/31306","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Silicon Nanoparticle Characterization by Fluorescence Correlation Spectroscopy","abstract":"Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-31T16:14:05Z Item is restricted indefinitely.","abstract_html":"Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-31T16:14:05Z Item is restricted indefinitely.","abstract_has_math":false,"creators":["Akcakir, Osman"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Gratton, E."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-05-31T16:14:05Z","date_published":"2012-05-31T16:14:05Z","updated_at":"2026-07-22T22:25:30Z","subjects":["Fluorescence Correlation Spectroscopy","Photon Counting Histogram","silicon nanocrystals"],"languages":["en"],"rights":["©2001 Osman Akcakir"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["4549687"],"render_values":[{"text":"4549687","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/31306","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gratton, E."]},{"key":"dc:creator","label":"Author","values":["Akcakir, Osman"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-05-31T16:14:05Z","2001"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Fluorescence Correlation Spectroscopy","Photon Counting Histogram","silicon nanocrystals"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["©2001 Osman Akcakir"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["4549687","http://hdl.handle.net/2142/31306"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-31T16:14:05Z Item is restricted indefinitely.","Open Restriction set for Item 31578 on 2019-05-28T18:16:20Z with date null by astein@illinois.edu.","Open Restriction set for Item 31578 on 2019-05-28T18:16:23Z with date null by astein@illinois.edu.","Access restriction removed with permission of the author. Made open access by astein on 2019-05-28","Open","This thesis aims to characterize the fluorescence brightness and size of silicon nanocrystals in solution by measuring equilibrium fluctuations through the techniques of Fluorescence Correlation Spectroscopy (FCS) as well as Photon Counting Histogram (PCH). It was found that Si nanocrystals are comparably bright to fluorescein, a standard organic fluorophore, as well as comparably small (~l.lnm in diameter). Imaging results on single Si nanocrystals show that individual nanocrystals are photostable for over 150s of continuous illumination, orders of magnitude longer than possible with traditional organic fluorophores under similar conditions. Due to the poorly controlled sonication step in the preparation of the Si nanocrystal colloid from the porous Si precursor, it was desirable to quantify the heterogeneity of the Si nanocrystal colloid. This was achieved by extending the techniques of FCS and PCH by scanning the excitation energy. In this way each fraction excited at a given wavelength could be counted, and a spectrum of number density versus excitation wavelength could be built up. By directly measuring the molecular heterogeneity in this way it was found that there exists significant heterogeneity in the Si nanocrystal preparations (i.e. the number density changes as a function of excitation wavelength). This important new observable (number density spectrum) can now be used as a control variable in refining the production of Si nanocrystal colloids in the effort to produce homogenous samples, which would be a necessary condition for applications. Traditional ensemble techniques (fluorescence emission/excitation spectra, fluorescence lifetime) are also performed, corroborating the conclusion of heterogeneity, though such techniques are not able to quantify it at the molecular level.","Submitted by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-31T16:14:05Z No. of bitstreams: 1 2001_akcakir.pdf: 4909483 bytes, checksum: 25a4e83338be2a88a7d12f4e1b781b46 (MD5)","Made available in DSpace on 2012-05-31T16:14:05Z (GMT). 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Made open access by astein on 2019-05-28","Open","This thesis aims to characterize the fluorescence brightness and size of silicon nanocrystals in solution by measuring equilibrium fluctuations through the techniques of Fluorescence Correlation Spectroscopy (FCS) as well as Photon Counting Histogram (PCH). It was found that Si nanocrystals are comparably bright to fluorescein, a standard organic fluorophore, as well as comparably small (~l.lnm in diameter). Imaging results on single Si nanocrystals show that individual nanocrystals are photostable for over 150s of continuous illumination, orders of magnitude longer than possible with traditional organic fluorophores under similar conditions. Due to the poorly controlled sonication step in the preparation of the Si nanocrystal colloid from the porous Si precursor, it was desirable to quantify the heterogeneity of the Si nanocrystal colloid. This was achieved by extending the techniques of FCS and PCH by scanning the excitation energy. In this way each fraction excited at a given wavelength could be counted, and a spectrum of number density versus excitation wavelength could be built up. By directly measuring the molecular heterogeneity in this way it was found that there exists significant heterogeneity in the Si nanocrystal preparations (i.e. the number density changes as a function of excitation wavelength). This important new observable (number density spectrum) can now be used as a control variable in refining the production of Si nanocrystal colloids in the effort to produce homogenous samples, which would be a necessary condition for applications. Traditional ensemble techniques (fluorescence emission/excitation spectra, fluorescence lifetime) are also performed, corroborating the conclusion of heterogeneity, though such techniques are not able to quantify it at the molecular level.","Submitted by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-31T16:14:05Z No. of bitstreams: 1 2001_akcakir.pdf: 4909483 bytes, checksum: 25a4e83338be2a88a7d12f4e1b781b46 (MD5)","Made available in DSpace on 2012-05-31T16:14:05Z (GMT). No. of bitstreams: 1 2001_akcakir.pdf: 4909483 bytes, checksum: 25a4e83338be2a88a7d12f4e1b781b46 (MD5) Previous issue date: 2001","Restriction data tranferred 2014-07-01T11:10:52-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: thesis"],"dc:identifier":["4549687","http://hdl.handle.net/2142/31306"],"dc:language":["en"],"dc:rights":["©2001 Osman Akcakir"],"dc:subject":["Fluorescence Correlation Spectroscopy","Photon Counting Histogram","silicon nanocrystals"],"dc:title":["Silicon Nanoparticle Characterization by Fluorescence Correlation Spectroscopy"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:30Z"}