Cellulose Nanocrystal Based Chiral Structures for Photonic Applications
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10362/156037 |
Resumo: | This thesis documents the fabrication and characterization of flexible ultraviolet (UV) sensors based on cellulose nanocrystals (CNC) as photonic films, for circularly polarized light sensing. The produced films exhibit an inherent left-handed chiral nematic structure which can be used as a filter for CPL in the visible range, where left CPL is reflected and right CPL is transmitted (LCPL and RCPL, respectively), creating a photonic bandgap. This property will be one of the focuses of the final device, allowing the production of specific electronic outputs depending on the polarization of the irradiating light. One of the main objectives of this work is the modulation of the photonic bandgap using potassium hydroxide, allowing for the tuna-bility of the workable spectrum (near-UV to red visible light). The second objective is the im-plementation of the photonic film into a UV sensor capable of distinguishing between R- and LCPL. The sensing layer is a zinc oxide (ZnO) ink with carbon contacts, deposited by screen-printing. The device was then encapsulated between cellulose acetate and characterized. Op-tical characterization shows a blue shift of the photonic bandgap with the addition of potas-sium hydroxide (from 700 nm with no substitutions to 430 nm with 150% substitution) result-ing in a near-linear relation between the photonic bandgap and increasing addition of the hy-droxide without relevant modification in the structure of the crystal. Electrical characterization presents an electronic signal distinction between left and right CPL ranging from 5-15%. |
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Cellulose Nanocrystal Based Chiral Structures for Photonic ApplicationsCellulose NanocrystalsPhotonic CrystalLiquid CrystalFlexible OptoelectronicsUltraviolet SensorDomínio/Área Científica::Engenharia e Tecnologia::NanotecnologiaThis thesis documents the fabrication and characterization of flexible ultraviolet (UV) sensors based on cellulose nanocrystals (CNC) as photonic films, for circularly polarized light sensing. The produced films exhibit an inherent left-handed chiral nematic structure which can be used as a filter for CPL in the visible range, where left CPL is reflected and right CPL is transmitted (LCPL and RCPL, respectively), creating a photonic bandgap. This property will be one of the focuses of the final device, allowing the production of specific electronic outputs depending on the polarization of the irradiating light. One of the main objectives of this work is the modulation of the photonic bandgap using potassium hydroxide, allowing for the tuna-bility of the workable spectrum (near-UV to red visible light). The second objective is the im-plementation of the photonic film into a UV sensor capable of distinguishing between R- and LCPL. The sensing layer is a zinc oxide (ZnO) ink with carbon contacts, deposited by screen-printing. The device was then encapsulated between cellulose acetate and characterized. Op-tical characterization shows a blue shift of the photonic bandgap with the addition of potas-sium hydroxide (from 700 nm with no substitutions to 430 nm with 150% substitution) result-ing in a near-linear relation between the photonic bandgap and increasing addition of the hy-droxide without relevant modification in the structure of the crystal. Electrical characterization presents an electronic signal distinction between left and right CPL ranging from 5-15%.A seguinte tese documenta a fabricação e caracterização de sensores ultravioleta (UV) em substrato flexível com base em celulose nano-cristalina na forma de filmes fotónicos, tornando possível reconhecer diferentes polarizações de luz circularmente polarizada (LCP). Os filmes produzidos exibem uma estrutura quiral nemática esquerda capaz de filtrar LCP na gama da luz visível, onde LCP direita é refletida e LCP esquerda é transmitida (LCPD e LCPE, respetivamente), criando assim um hiato fotónico. Esta propriedade vai ser o foco do funcionamento do dispositivo final, possibilitando a produção de sinais eletrónicos distintos para as diferentes polarizações de luz incidida. Um dos principais objetivos deste trabalho é a modificação do hiato fotónico usando hidróxido de potássio, possibilitando uma modulação do espetro trabalhado (gama entre near-UV e visível). O segundo objetivo é a implementação do filme fotónico num sensor UV capaz de distinguir entre LCPD e LCPE. A camada sensível é produzida usando tinta de óxido de zinco (ZnO) e contactos de carbono, depositados através de screen-printing. O dispositivo foi encapsulado entre acetato de celulose e caracterizado. Analisando os resultados da caracterização ótica foi possível identificar uma transição do hiato fotónico para o azul com a adição do hidróxido de potássio (de um hiato nos 700 nm sem substituições para 430 nm com a substituição de 150%) resultando numa relação quásilinear entre o hiato fotónico e o aumento de hidróxido de potássio adicionado, sem alterações relevantes na estrutura do cristal. Caracterização elétrica revela uma distinção de sinal elétrico entre as duas polarizações entre 5-15%.Gaspar, DianaPereira, LuísRUNMendes, Bruno Martins2023-07-31T14:19:01Z2022-112022-11-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/156037enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T05:38:27Zoai:run.unl.pt:10362/156037Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:56:14.712590Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
title |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
spellingShingle |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications Mendes, Bruno Martins Cellulose Nanocrystals Photonic Crystal Liquid Crystal Flexible Optoelectronics Ultraviolet Sensor Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia |
title_short |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
title_full |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
title_fullStr |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
title_full_unstemmed |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
title_sort |
Cellulose Nanocrystal Based Chiral Structures for Photonic Applications |
author |
Mendes, Bruno Martins |
author_facet |
Mendes, Bruno Martins |
author_role |
author |
dc.contributor.none.fl_str_mv |
Gaspar, Diana Pereira, Luís RUN |
dc.contributor.author.fl_str_mv |
Mendes, Bruno Martins |
dc.subject.por.fl_str_mv |
Cellulose Nanocrystals Photonic Crystal Liquid Crystal Flexible Optoelectronics Ultraviolet Sensor Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia |
topic |
Cellulose Nanocrystals Photonic Crystal Liquid Crystal Flexible Optoelectronics Ultraviolet Sensor Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia |
description |
This thesis documents the fabrication and characterization of flexible ultraviolet (UV) sensors based on cellulose nanocrystals (CNC) as photonic films, for circularly polarized light sensing. The produced films exhibit an inherent left-handed chiral nematic structure which can be used as a filter for CPL in the visible range, where left CPL is reflected and right CPL is transmitted (LCPL and RCPL, respectively), creating a photonic bandgap. This property will be one of the focuses of the final device, allowing the production of specific electronic outputs depending on the polarization of the irradiating light. One of the main objectives of this work is the modulation of the photonic bandgap using potassium hydroxide, allowing for the tuna-bility of the workable spectrum (near-UV to red visible light). The second objective is the im-plementation of the photonic film into a UV sensor capable of distinguishing between R- and LCPL. The sensing layer is a zinc oxide (ZnO) ink with carbon contacts, deposited by screen-printing. The device was then encapsulated between cellulose acetate and characterized. Op-tical characterization shows a blue shift of the photonic bandgap with the addition of potas-sium hydroxide (from 700 nm with no substitutions to 430 nm with 150% substitution) result-ing in a near-linear relation between the photonic bandgap and increasing addition of the hy-droxide without relevant modification in the structure of the crystal. Electrical characterization presents an electronic signal distinction between left and right CPL ranging from 5-15%. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-11 2022-11-01T00:00:00Z 2023-07-31T14:19:01Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10362/156037 |
url |
http://hdl.handle.net/10362/156037 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799138148147527680 |