{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/106321"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/106321","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Alloyed heterojunction nanorods and their applications","abstract":"In the Shim research lab, we work to both synthesize novel nanomaterials and integrate them into electronic devices. The goal of my research was to improve the utility of our existing heterostructures in optoelectronic devices, and my main tool was alloying. The first half of my dissertation focuses on CdSe/CdTe heterojunction nanorods for use in photovoltaics. First, I utilized a simple post-synthesis ligand exchange procedure to greatly improve their environmental stability. Then, we integrated them into sensitized solar cells. By alloying CdTe with Se through a slow-injection procedure and by adopting a partial core/shell morphology, we were able to better balance light absorption with charge extraction and ultimately achieve solar cells with 5.9% power conversion efficiency. The latter half of my dissertation focuses on our group's flagship material, the double-heterojunction nanorod, which can outperform traditional quantum dots in red light-emitting diodes. I investigated methods to alloy the emitting material while maintaining proper energy band alignment in the heterostructure, with the goal of extending the emission range to green or even blue. I developed a new two-step cation exchange process to alloy the nanorods with Zn while preserving their shape. With subsequent shell growth, we can achieve single-peak photoluminescence spanning the entire visible spectrum (400 – 635 nm).","abstract_html":"In the Shim research lab, we work to both synthesize novel nanomaterials and integrate them into electronic devices. The goal of my research was to improve the utility of our existing heterostructures in optoelectronic devices, and my main tool was alloying. The first half of my dissertation focuses on CdSe/CdTe heterojunction nanorods for use in photovoltaics. First, I utilized a simple post-synthesis ligand exchange procedure to greatly improve their environmental stability. Then, we integrated them into sensitized solar cells. By alloying CdTe with Se through a slow-injection procedure and by adopting a partial core/shell morphology, we were able to better balance light absorption with charge extraction and ultimately achieve solar cells with 5.9% power conversion efficiency. The latter half of my dissertation focuses on our group's flagship material, the double-heterojunction nanorod, which can outperform traditional quantum dots in red light-emitting diodes. I investigated methods to alloy the emitting material while maintaining proper energy band alignment in the heterostructure, with the goal of extending the emission range to green or even blue. I developed a new two-step cation exchange process to alloy the nanorods with Zn while preserving their shape. With subsequent shell growth, we can achieve single-peak photoluminescence spanning the entire visible spectrum (400 – 635 nm).","abstract_has_math":false,"creators":["Flanagan, Joseph C."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Shim, Moonsub","Zuo, Jian-Min","Shoemaker, Daniel","van der Veen, Renske"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-03-02T22:12:09Z","date_published":"2020-03-02T22:12:09Z","updated_at":"2026-07-22T22:24:45Z","subjects":["semiconductor","nanocrystal","led","solar cell"],"languages":["en"],"rights":["Copyright 2019 Joseph Flanagan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/106321","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shim, Moonsub","Zuo, Jian-Min","Shoemaker, Daniel","van der Veen, Renske"]},{"key":"dc:creator","label":"Author","values":["Flanagan, Joseph C."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-03-02T22:12:09Z","2022-03-03T10:15:25Z","2019-10-09","2019-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["semiconductor","nanocrystal","led","solar cell"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Joseph Flanagan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/106321"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In the Shim research lab, we work to both synthesize novel nanomaterials and integrate them into electronic devices. The goal of my research was to improve the utility of our existing heterostructures in optoelectronic devices, and my main tool was alloying. The first half of my dissertation focuses on CdSe/CdTe heterojunction nanorods for use in photovoltaics. First, I utilized a simple post-synthesis ligand exchange procedure to greatly improve their environmental stability. Then, we integrated them into sensitized solar cells. By alloying CdTe with Se through a slow-injection procedure and by adopting a partial core/shell morphology, we were able to better balance light absorption with charge extraction and ultimately achieve solar cells with 5.9% power conversion efficiency. The latter half of my dissertation focuses on our group's flagship material, the double-heterojunction nanorod, which can outperform traditional quantum dots in red light-emitting diodes. I investigated methods to alloy the emitting material while maintaining proper energy band alignment in the heterostructure, with the goal of extending the emission range to green or even blue. I developed a new two-step cation exchange process to alloy the nanorods with Zn while preserving their shape. With subsequent shell growth, we can achieve single-peak photoluminescence spanning the entire visible spectrum (400 – 635 nm).","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Joseph Flanagan, accepted the attached license on 2019-10-03 at 09:58.","The student, Joseph Flanagan, submitted this Dissertation for approval on 2019-10-03 at 10:03.","This Dissertation was approved for publication on 2019-10-09 at 15:11.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14479 on 2020-02-28 at 17:20:53","Made available in DSpace on 2020-03-02T22:12:09Z (GMT). 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I investigated methods to alloy the emitting material while maintaining proper energy band alignment in the heterostructure, with the goal of extending the emission range to green or even blue. I developed a new two-step cation exchange process to alloy the nanorods with Zn while preserving their shape. With subsequent shell growth, we can achieve single-peak photoluminescence spanning the entire visible spectrum (400 – 635 nm).","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01","The student, Joseph Flanagan, accepted the attached license on 2019-10-03 at 09:58.","The student, Joseph Flanagan, submitted this Dissertation for approval on 2019-10-03 at 10:03.","This Dissertation was approved for publication on 2019-10-09 at 15:11.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14479 on 2020-02-28 at 17:20:53","Made available in DSpace on 2020-03-02T22:12:09Z (GMT). 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