Este trabalho de tese apresenta novas evidências experimentais que ajudam no conhecimento atual das propriedades de transporte em semicondutores orgânicos, aprofundando o conhecimento dos processos de condução dependentes de spin em dispositivos eletrônicos baseados nestes materiais. O trabalho apresentado pode ser dividido em dois temas principais, o primeiro relacionado ao aumento das qualidades espectroscópicas da técnica de ressonância magnética detectada eletricamente (RMDE) por meio de um estudo da dependência do sinal vetorial de RMDE em função da freqüência do campo magnético de modulação. O segundo tema, encontrase relacionado aos efeitos de campos magnéticos externos na condutividade de semicondutores orgânicos. Através de uma análise de fase cuidadosa do sinal vetorial de RMDE foi demonstrado que o espectro de RMDE de diodos orgânicos emissores de luz (OLEDs) baseados em alumínio (III) 8-hidroxiquinolina (\'Alq IND. 3\') pôde ser separado em dois sinais componentes com fatores-g de: \'g IND. h\'= 2,007 e \'g IND. e\'= 2,0035. O espectro de RMDE de OLEDs baseados em \'Alq IND. 3\' foi atribuído ao processo de formação de éxcitons, e os sinais componentes foram atribuídos ao par precursor do éxciton, um à ressonância em ânions de \'Alq IND. 3\', enquanto que o outro a estados catiônicos no \'Alq IND. 3\'. Foi demonstrado que a utilização de diferentes freqüências de modulação de campo magnético aumenta a resolução temporal do sistema de detecção de RMDE, não influenciando os valores dos parâmetros espectroscópicos dos sinais. Desta forma, foi observado que os sistemas ou processos dependentes de spin diferentes que dão origem ao sinal de RMDE de OLEDs baseados em \'Alq IND. 3\', têm uma diferença entre os tempos de resposta menor que 6.0 x \'10 POT. -7\'s. Neste trabalho se propõe um modelo de circuito para simular a origem do sinal de RMDE de OLEDs baseados em \'Alq IND. 3\'. Os resultados deste modelo têm uma grande concordância com os resultados experimentais, observando-se que os dois sistemas ou processos de spin diferentes que dão origem ao sinal, podem ser representados por uma combinação paralela de capacitâncias e \"resistores\" que tomam a forma de funções gaussianas em condições de ressonância magnética. A generalidade deste modelo indica que ele poderia ser utilizado em outros problemas de transporte dependentes de spin de outros dispositivos eletrônicos orgânicos, inorgânicos ou híbridos (inorgânico-orgânico). Resultados de estudos de RMDE de OLEDs baseados em \'Alq IND. 3\', dopados e não dopados, em baixas temperaturas (até 100 K), mostraram que no OLED dopado com rubreno pode existir um mecanismo de formação de éxcitons similar ao já observado para o OLED dopado com DCM-TPA, indicando que o mecanismo de formação de éxcitons no OLED dopado com rubreno seria uma reação direta entre um elétron no \'Alq IND. 3\' com um buraco aprisionado no dopante. Foram observados efeitos do campomagnético na condutividade de dispositivos baseados em semicondutores orgânicos demonstrando a ocorrência do fenômeno de magneto-resistência (MR) em dispositivos orgânicos e híbridos (orgânico-inorgânico). Estes estudos mostraram que a melhor forma de detecção destes efeitos é através do monitoramento da resistência em função do tempo sob a aplicação de campos magnéticos externos. Para os dispositivos baseados em \'Alq IND. 3\', OLEDs dopados e não dopados e um dispositivo e-only, foi observada somente MR negativa, enquanto que para um dispositivo h-only foi observado um novo efeito quase constante e positivo. Para campos magnéticos aplicados de até 1 T, os dispositivos unipolares mostraram baixos efeitos de campo magnético na condutividade alcançando MR de até 0,08%, enquanto que os OLEDs mostraram efeitos maiores alcançando MR de até 3,2%. Apesar do mecanismo exato que origina os efeitos de campo magnético na condutividade de semicondutores orgânicos ainda permanecer desconhecido, os resultados apresentados neste trabalho indicam que este fenômeno não está relacionado com a formação de éxcitons. / This thesis presents new experimental evidences that can improve the current knowledge of the transport properties in organic semiconductors, particularly the spin dependent conduction processes in electronic devices based in those materials. This work can be divided in two main subjects, the first one related to the increasing in the spectroscopic qualities of the electrically detected magnetic resonance (EDMR) technique and the second one related to the external magnetic field effects in the conductivity of the organic semiconductors. Using a careful phase analysis of the vectorial EDMR signal it was demonstrated that the aluminium (III) 9-hydroxyquinoline (\'Alq IND. 3\')-based organic light emitting diodes (OLEDs) spectrum cam be separated in two component signais with different g-factors: \"G IND. h\'= 2,007 and \'g IND. e\'= 2,0035. The EDMR spectrum of \'Alq IND. 3\'-based OLEDs was attributed to the exciton formation process and the component signals were attributed to the resonance in \'Alq IND. 3\' anions (electrons) and in cationic states (holes) into \'Alq IND. 3\'. It was demonstrated that the use of different magnetic field modulations frequencies (MFMF) improves the temporal resolution of the EDMR system detection. It observed that the difference in the lifetime of the two EDMR signal components is smaller than 6.0x\'10 POT -7\'s. We proposed a novel circuit model to explain the observed EDMR signals. Results from this model are in agreement with the experimentalresults showing that the EDMR signal of \'Alq IND. 3\'-based OLEDS comes fromtwo different spin systems that can be represented by a parallel combination of capacitance and resistances which acquires a Gaussian form is magnetic resonance conditions. The simplest circuit model indicates that it can be used in other spin-dependent transport problems of different electronic devices (organic, inorganic or hybrid) studied by EDMR experiments. Results from a EDMR investigation of the effects of dye doping on spin dependent exciton formation in \'Alq IND. 3\'-based OLEDs at low temperatures (up to 100 K) showed that the Rubrene dye doped \'Alq IND. 3\'-based OLEDs presents a similar mechanism for exciton formation that the DCM--TPA doped OLED indicating that the recombination occurs by a direct reaction between an electron in the \'Alq IND. 3\' and a hole into the dopant. Magnetic field effects in the conductivity of organic semiconductors based devices were observed, showing the existence of the magnetoresistance (MR) phenomena in both organic and hybrids (organic-inorganic) devices. The studies showed that the best way to detect this effects is by monitoring the resistance as a function of time under the application of different magnetic field pulses. Only negative magnetoresistance was observed for the \'Alq IND. 3\'-based devices: undoped and dye doped OLEDs and an electron only device. A very small, positive and almost constant MR was observedin the hole-only device. For the unipolar devices were observed small magnetic field effects in the conductivity reaching a MR= 0.08%. The OLEDs showed bigger effects reaching a MR= 3.2%. Despite the exact mechanism that origins the magnetic field effects in the conductivity of organic semiconductors remains unknown the results presented in this thesis indicates that this phenomena is not related to the exciton formation.

A presente tese de doutorado apresenta um estudo comparativo das características elétricas de dispositivos emissores de luz poliméricos (PLEDs) confeccionados com óxido de índio dopado com zinco (IZO) como eletrodo transparente alternativamente ao ITO comumente usado em dispositivos poliméricos. As propriedades elétricas de filmes de IZO depositados a frio foram obtidas através da técnica de impedanciometria. Descrevemos detalhadamente todo o processo de fabricação dos dispositivos, com os respectivos eletrodos, em estrutura simples ou contendo uma camada adicional de PEDOT. Dois polímeros luminescentes foram utilizados como camada ativa em nossos dispositivos: MEH-PPV e uma blenda de derivados de Polifluoreno. Nossos resultados mostram que o IZO apresenta todas as características para substituir o ITO enquanto anodo transparente em dispositivos optoeletrônicos poliméricos. Realizamos estudos detalhados das propriedades elétricas de dispositivos fabricados com MEH-PPV e com blendas de derivados de polifluorenos, com ITO ou com IZO e com ou sem camada intermediária de PEDOT, e para isso usamos as técnicas de medida estacionária (J-V) e alternada (impedanciometria). Os resultados foram analisados à luz dos modelos de injeção de Arkhipov, para resposta estacionária, e de circuitos equivalentes e de Dyre para espectroscopia em freqüência. Ao modelo de Arkhipov, adicionamos um termo de corrente de tunelamento que melhorou o ajuste para região de campos altos. Dos ajustes teórico-experimentais obtivemos importantes parâmetros dos dispositivos. / In this thesis we presented a detailed study of polymer light-emitting diodes (PLEDs) made with IZO as transparent electrode alternative to ITO. The electrical properties of thin film of IZO were studied by impedance measurements. Measurements with devices containing an additional transport layer of PEDOT were also performed. We used two different thin polymeric films for such studies: the MEH-PPV and a blend made by two polyfluorene derivatives. We also carried out a detailed investigation of several devices, making use of two techniques: by stationary J-V and by impedance measurements. The results were analyzed by the Arkhipov model (for stationary results), and by equivalent circuits and Dyre´s model for the spectroscopic results. We introduced an additional term of tunneling effect to the Arkhipov model, which improved the theoretical fitting over the experimental results at high fields. From the fittings we obtained important parameters of the produced devices.

Ce travail porte sur l'étude de la dégradation accélérées des diodes électroluminescentes organiques (OLEDs) pour l'éclairage. Nous avons choisi d'étudier des OLEDs commerciales (Philips lumiblade GL55 et OSRAM Orbeos RMW-046) afin d'éliminer l'effet de l'humidité et de l'oxygène et ainsi que les processus de fabrication sur les mécanismes de dégradation. Une étude bibliographique préalable nous a permis de comprendre les mécanismes de fonctionnement des OLEDs et d'analyser les différentes causes de dégradations. Elle nous a également permis de définir des conditions de vieillissement accéléré (stress thermique et électrique) que nous avons appliquées à nos échantillons. Afin d'appliquer ces conditions de stress particulières, nous avons conçu et réalisé un dispositif expérimental spécifique qui nous permet à la fois d'appliquer ces différentes conditions de vieillissement et de réaliser des mesures électriques et optiques in situ. Ces mesures ont été réalisées avant dégradation, puis jusqu'à une perte de 50% du flux lumineux. L'évolution des caractéristiques électriques et photométriques des OLEDs ainsi que certaines analyses structurales complémentaires nous ont permis d'établir et de comprendre les mécanismes mis en jeu. / This work reports on the study of accelerated ageing of white organic light-emitting diodes (OLEDs) for lighting. We chose to apply our study on commercial products (Philips lumiblade GL55 and OSRAM Orbeos RMW-046) to eliminate the moisture, oxygen and manufacturing process effects on the degradation mechanisms. A preliminary bibliographic study enabled us to understand the operation mechanism of the OLEDs and to analyze the different degradation causes. This one also allowed us to determine the accelerated ageing test conditions (thermal and electrical stresses). In order, to apply these particular stress conditions, we designed and realized a specific and custom-made experimental ageing bench which allows us at the same time to apply these various ageing conditions and carry out electrical and optical measurement in situ. These measurements were realized before degradations and then until a loss of 50% of the luminous flow. The evolution of the electrical and optical characteristics of the OLEDs as well as the results obtained from some additional structural analysis enabled us to establish and understand the involved mechanisms.

A presente tese de doutorado apresenta um estudo comparativo das características elétricas de dispositivos emissores de luz poliméricos (PLEDs) confeccionados com óxido de índio dopado com zinco (IZO) como eletrodo transparente alternativamente ao ITO comumente usado em dispositivos poliméricos. As propriedades elétricas de filmes de IZO depositados a frio foram obtidas através da técnica de impedanciometria. Descrevemos detalhadamente todo o processo de fabricação dos dispositivos, com os respectivos eletrodos, em estrutura simples ou contendo uma camada adicional de PEDOT. Dois polímeros luminescentes foram utilizados como camada ativa em nossos dispositivos: MEH-PPV e uma blenda de derivados de Polifluoreno. Nossos resultados mostram que o IZO apresenta todas as características para substituir o ITO enquanto anodo transparente em dispositivos optoeletrônicos poliméricos. Realizamos estudos detalhados das propriedades elétricas de dispositivos fabricados com MEH-PPV e com blendas de derivados de polifluorenos, com ITO ou com IZO e com ou sem camada intermediária de PEDOT, e para isso usamos as técnicas de medida estacionária (J-V) e alternada (impedanciometria). Os resultados foram analisados à luz dos modelos de injeção de Arkhipov, para resposta estacionária, e de circuitos equivalentes e de Dyre para espectroscopia em freqüência. Ao modelo de Arkhipov, adicionamos um termo de corrente de tunelamento que melhorou o ajuste para região de campos altos. Dos ajustes teórico-experimentais obtivemos importantes parâmetros dos dispositivos. / In this thesis we presented a detailed study of polymer light-emitting diodes (PLEDs) made with IZO as transparent electrode alternative to ITO. The electrical properties of thin film of IZO were studied by impedance measurements. Measurements with devices containing an additional transport layer of PEDOT were also performed. We used two different thin polymeric films for such studies: the MEH-PPV and a blend made by two polyfluorene derivatives. We also carried out a detailed investigation of several devices, making use of two techniques: by stationary J-V and by impedance measurements. The results were analyzed by the Arkhipov model (for stationary results), and by equivalent circuits and Dyre´s model for the spectroscopic results. We introduced an additional term of tunneling effect to the Arkhipov model, which improved the theoretical fitting over the experimental results at high fields. From the fittings we obtained important parameters of the produced devices.

Este trabalho de tese apresenta novas evidências experimentais que ajudam no conhecimento atual das propriedades de transporte em semicondutores orgânicos, aprofundando o conhecimento dos processos de condução dependentes de spin em dispositivos eletrônicos baseados nestes materiais. O trabalho apresentado pode ser dividido em dois temas principais, o primeiro relacionado ao aumento das qualidades espectroscópicas da técnica de ressonância magnética detectada eletricamente (RMDE) por meio de um estudo da dependência do sinal vetorial de RMDE em função da freqüência do campo magnético de modulação. O segundo tema, encontrase relacionado aos efeitos de campos magnéticos externos na condutividade de semicondutores orgânicos. Através de uma análise de fase cuidadosa do sinal vetorial de RMDE foi demonstrado que o espectro de RMDE de diodos orgânicos emissores de luz (OLEDs) baseados em alumínio (III) 8-hidroxiquinolina (\'Alq IND. 3\') pôde ser separado em dois sinais componentes com fatores-g de: \'g IND. h\'= 2,007 e \'g IND. e\'= 2,0035. O espectro de RMDE de OLEDs baseados em \'Alq IND. 3\' foi atribuído ao processo de formação de éxcitons, e os sinais componentes foram atribuídos ao par precursor do éxciton, um à ressonância em ânions de \'Alq IND. 3\', enquanto que o outro a estados catiônicos no \'Alq IND. 3\'. Foi demonstrado que a utilização de diferentes freqüências de modulação de campo magnético aumenta a resolução temporal do sistema de detecção de RMDE, não influenciando os valores dos parâmetros espectroscópicos dos sinais. Desta forma, foi observado que os sistemas ou processos dependentes de spin diferentes que dão origem ao sinal de RMDE de OLEDs baseados em \'Alq IND. 3\', têm uma diferença entre os tempos de resposta menor que 6.0 x \'10 POT. -7\'s. Neste trabalho se propõe um modelo de circuito para simular a origem do sinal de RMDE de OLEDs baseados em \'Alq IND. 3\'. Os resultados deste modelo têm uma grande concordância com os resultados experimentais, observando-se que os dois sistemas ou processos de spin diferentes que dão origem ao sinal, podem ser representados por uma combinação paralela de capacitâncias e \"resistores\" que tomam a forma de funções gaussianas em condições de ressonância magnética. A generalidade deste modelo indica que ele poderia ser utilizado em outros problemas de transporte dependentes de spin de outros dispositivos eletrônicos orgânicos, inorgânicos ou híbridos (inorgânico-orgânico). Resultados de estudos de RMDE de OLEDs baseados em \'Alq IND. 3\', dopados e não dopados, em baixas temperaturas (até 100 K), mostraram que no OLED dopado com rubreno pode existir um mecanismo de formação de éxcitons similar ao já observado para o OLED dopado com DCM-TPA, indicando que o mecanismo de formação de éxcitons no OLED dopado com rubreno seria uma reação direta entre um elétron no \'Alq IND. 3\' com um buraco aprisionado no dopante. Foram observados efeitos do campomagnético na condutividade de dispositivos baseados em semicondutores orgânicos demonstrando a ocorrência do fenômeno de magneto-resistência (MR) em dispositivos orgânicos e híbridos (orgânico-inorgânico). Estes estudos mostraram que a melhor forma de detecção destes efeitos é através do monitoramento da resistência em função do tempo sob a aplicação de campos magnéticos externos. Para os dispositivos baseados em \'Alq IND. 3\', OLEDs dopados e não dopados e um dispositivo e-only, foi observada somente MR negativa, enquanto que para um dispositivo h-only foi observado um novo efeito quase constante e positivo. Para campos magnéticos aplicados de até 1 T, os dispositivos unipolares mostraram baixos efeitos de campo magnético na condutividade alcançando MR de até 0,08%, enquanto que os OLEDs mostraram efeitos maiores alcançando MR de até 3,2%. Apesar do mecanismo exato que origina os efeitos de campo magnético na condutividade de semicondutores orgânicos ainda permanecer desconhecido, os resultados apresentados neste trabalho indicam que este fenômeno não está relacionado com a formação de éxcitons. / This thesis presents new experimental evidences that can improve the current knowledge of the transport properties in organic semiconductors, particularly the spin dependent conduction processes in electronic devices based in those materials. This work can be divided in two main subjects, the first one related to the increasing in the spectroscopic qualities of the electrically detected magnetic resonance (EDMR) technique and the second one related to the external magnetic field effects in the conductivity of the organic semiconductors. Using a careful phase analysis of the vectorial EDMR signal it was demonstrated that the aluminium (III) 9-hydroxyquinoline (\'Alq IND. 3\')-based organic light emitting diodes (OLEDs) spectrum cam be separated in two component signais with different g-factors: \"G IND. h\'= 2,007 and \'g IND. e\'= 2,0035. The EDMR spectrum of \'Alq IND. 3\'-based OLEDs was attributed to the exciton formation process and the component signals were attributed to the resonance in \'Alq IND. 3\' anions (electrons) and in cationic states (holes) into \'Alq IND. 3\'. It was demonstrated that the use of different magnetic field modulations frequencies (MFMF) improves the temporal resolution of the EDMR system detection. It observed that the difference in the lifetime of the two EDMR signal components is smaller than 6.0x\'10 POT -7\'s. We proposed a novel circuit model to explain the observed EDMR signals. Results from this model are in agreement with the experimentalresults showing that the EDMR signal of \'Alq IND. 3\'-based OLEDS comes fromtwo different spin systems that can be represented by a parallel combination of capacitance and resistances which acquires a Gaussian form is magnetic resonance conditions. The simplest circuit model indicates that it can be used in other spin-dependent transport problems of different electronic devices (organic, inorganic or hybrid) studied by EDMR experiments. Results from a EDMR investigation of the effects of dye doping on spin dependent exciton formation in \'Alq IND. 3\'-based OLEDs at low temperatures (up to 100 K) showed that the Rubrene dye doped \'Alq IND. 3\'-based OLEDs presents a similar mechanism for exciton formation that the DCM--TPA doped OLED indicating that the recombination occurs by a direct reaction between an electron in the \'Alq IND. 3\' and a hole into the dopant. Magnetic field effects in the conductivity of organic semiconductors based devices were observed, showing the existence of the magnetoresistance (MR) phenomena in both organic and hybrids (organic-inorganic) devices. The studies showed that the best way to detect this effects is by monitoring the resistance as a function of time under the application of different magnetic field pulses. Only negative magnetoresistance was observed for the \'Alq IND. 3\'-based devices: undoped and dye doped OLEDs and an electron only device. A very small, positive and almost constant MR was observedin the hole-only device. For the unipolar devices were observed small magnetic field effects in the conductivity reaching a MR= 0.08%. The OLEDs showed bigger effects reaching a MR= 3.2%. Despite the exact mechanism that origins the magnetic field effects in the conductivity of organic semiconductors remains unknown the results presented in this thesis indicates that this phenomena is not related to the exciton formation.

The majority of research on Organic Light-Emitting Diodes (OLEDs) has focused on a top-cathode, conventional bottom-emitting architecture. Yet bottom-cathode, inverted top-emitting OLEDs offer some advantages from an applications point of view. In this thesis, the development of high performance green electroluminescent inverted top-emitting diodes is first presented. The challenges in producing an inverted structure are discussed and the advantages of high efficiency inverted top-emitting OLEDs are provided. Next, the transition to a stacked architecture with separate orange and blue emitting layers is demonstrated, allowing for white emission. The pros and cons of the existing device structure is described, with an eye to future developments and proposed follow-up research.

Display technology has become a vital and ubiquitous part of our daily life. Undoubtedly, today’s technologically minded society is living in the era of the digital image. After high resolution and efficiency could successfully be realized, the major trends in display technology now aim towards achieving high color purity for natural looking display colors. Organic light-emitting diodes (OLEDs), as one strong contender for high performance displays and lighting, have been undergoing tremendous industrial and commercial development. Despite the great progress, though, there is still space for improvement, especially in the case of blue light emitting devices. Blue OLEDs are always challenging, since they traditionally suffer from low efficiencies and lifetimes. Both, novel materials and device architectures, are driving ongoing developments while still always aiming to lower the overall costs. In a continual effort to search for robust materials for blue devices, small molecules (SMs) and polymers, are shown to be promising candidates. In this thesis is presented the results of the detailed study of photophysical and electroluminescence (EL) properties in the case of thin films based on blends of the conjugated polymer Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) and the of novel SMs; 4,4'-(anthracene-9,10-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (TPAA) and 4,4'-(pyrene-1,6-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (TPAP). Finally, devices based on these systems are optimized step by step as a solution processable emissive layer (EML), for applications in sky blue OLEDs.

The purpose of this thesis was to develop the first examples of multifunctional triarylboron-functionalized 8-hydroxyquinoline, their respective aluminum (III) complexes, Al(1)3 and Al(2)3, and diboron analogues, B1 and B2. There was particular focus in investigating the electron accepting characteristics of these systems for potential use as electron transport materials (ETMs) in organic light emitting diodes (OLEDs). The first part of the thesis will discuss the aluminum complexes. Through the introduction of the triarylboron moiety these derivatives of the well-known ETM tris(8-hydroxyquinoline)aluminum (Alq3) exhibited better electron accepting properties than the parent compound. Furthermore, the complexes were able to act as sensors and indicators towards soft Lewis acids such as CN- and hard Lewis acids such as F-, respectively. First the structures of the compounds were investigated using COSY NMR, leading to the discovery that similar to Alq3 the new aluminum complexes possessed the commonly observed mer-isomeric form. Furthermore, their photophysical characteristics were investigated using UV-Vis and fluorescence spectroscopic measurements. The solid state fluorescence quantum yield of Al(1)3 (Φ=0.06) and Al(2)3 (Φ=0.02) were measured and compared to Alq3 (Φ=0.14). In order to better understand these results and gain insight into the electronic transitions of the aluminum complexes, DFT calculations were employed using the B3LYP/6-31G* level of theory. The second part of the thesis will discuss the only examples of diboron-functionalized 8-hydroxyquinoline complexes to date, with one three-coordinate and one four-coordinate boron moiety. Based on CV measurements and DFT calculations, it was discovered that the LUMO of the diboron compounds were lowered substantially compared to their aluminum analogues discussed earlier. More interestingly, it was found that only B1 has any contributions to its LUMO from the triarylboron moiety, leading to the slightly stronger electron accepting ability of B1 compared to B2. Furthermore, these compounds were both able to act as sensors towards small anions such as F-. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-21 08:43:10.543

This work concerns the development of π-conjugated materials for optoelectronic applications, with emphasis on organoboron- and organoplatinum-containing compounds. The preparation of a nonconjugated two-chromophore emissive material is described, containing both organoplatinum and organoboron units. This material exhibits simultaneous fluorescent and phosphorescent emission at ambient temperature. Both emission colours are switchable in the presence of fluoride, giving a dual-emissive compound with multiple observable luminescent colours. The preparation of a nonconjugated donor-acceptor triarylborane containing both Lewis acidic and basic receptor sites is also described. This highly fluorescent compound is reversibly switchable between three emissive states upon addition of acid or fluoride. Furthermore, platinum(II)-acetylacetonates with nonconjugated antenna chromophores were prepared, and their luminescent properties were investigated. A series of directly conjugated platinum(II)-acetylacetonates have been synthesized incorporating a triarylboron group. The presence of boron was found to enhance the electron-transporting capabilities, film-forming properties, and phosphorescent quantum yields of these complexes. Highly efficient OLEDs were prepared incorporating these materials as dopants, including the first example of a Pt(II)-based OLED with an external quantum efficiency >20%. Triarylboron-containing Pt(II) complexes of N-heterocyclic carbenes were also prepared. Using this design, blue to blue-green phosphorescence was achieved with high quantum yield, and their use in OLEDs was demonstrated. A new high-yield synthetic route has been developed to cyclometalated Pt(II)-β-diketonates, requiring stoichiometric reagents and short reaction times at ambient temperature. This methodology has broad substrate scope across a variety of N^C-chelate ligands, as well as P^C-chelate phosphines and C^C-chelate carbenes as well. The preparation of N-heterocyclic carbazole-based host materials for OLEDs is also described. These materials exhibit improved electron-transporting capabilities relative to the more commonly used host 4,4’-N,N’-dicarbazolylbiphenyl (CBP), and were used to fabricate the first single-layer electrophosphorescent devices with efficiencies competitive with conventional multilayer structures. Finally, the discovery of a triarylboron-based vapochromic material is described. This Pt(II)-alkyne complex was shown to change luminescent colour in response to a variety of volatile organic compounds, with distinct responses dependent on the nature of the analyte. The mechanism of vapochromism was investigated in detail by optical and multinuclear solid-state NMR spectroscopy, and differs in origin from all previously reported examples. / Thesis (Ph.D, Chemistry) -- Queen's University, 2012-09-06 12:51:18.363

Ce travail de thèse porte sur la synthèse et la caractérisation physico-chimique de métallopolymères conjugués des éléments f en but d’utiliser ces matériaux comme composants actifs de diodes électroluminescentes. En effet, les ions lanthanides possèdent des propriétés d’émission intéressantes dans le cadre de nos applications. La chaine polymère permet quant à elle l’introduction de groupements transporteurs de charges. Ces matériaux devraient donc réunir les caractéristiques requises (transport des charges et émission) pour être utilisés dans des PLEDs (Polymer Light-Emitting Diodes), lesquelles emploient pour leur fabrication des techniques de dépôts en solution. Les PLEDs présentent l’intérêt d’avoir une structure simplifiée par rapport aux OLEDs (Organic Light-Emitting Diodes) qui sont construites par juxtaposition de couches successives de petites molécules évaporées sous vide.La synthèse de trois séries de polymères conjugués a été réalisée. La réaction de polymérisation utilisée s’effectue selon un couplage de Suzuki-Miyaura entre des motifs fluorènes et des monomères porteurs de groupements carbazoles et/ou benzimidazoles permettant de coordiner l’ion lanthanide. Plusieurs métallopolymères ont également été isolés. Les composés synthétisés ont été caractérisés par analyse élémentaire, RMN et chromatographie par exclusion stérique. Des études de photoluminescence sur ces composés en présence ou non d’ions lanthanides luminescents ont été effectuées. Enfin, les polymères et métallopolymères ont été utilisés dans la conception de diodes électroluminescentes. / This work deals with the synthesis and physico-chemical characterization of lanthanide-containing metallopolymers to use them as active components in electroluminescent diodes. The emission properties of trivalent lanthanides are particularly interesting in the case of our application. The conjugated chain polymer built up with charge-transport groups. These materials should provide all the properties (conduction and emission) to be used as active layer in PLEDs (Polymer Light-Emitting Diodes) which are devices made by solution deposition techniques. The PLEDs offer the advantage to have a simplified structure in comparison with OLEDs (Organic Light-Emitting Diodes) which are built by juxtaposition of layers constituted by small organic molecules.The syntheses of three series of conjugated polymers have been achieved. The polymerization reaction has been carried out by a Pd-catalyzed Suzuki-Miyaura coupling between fluorenes moieties and monomers bearing carbazole and/or benzimidazole groups acting as a coordinating site for the lanthanide ion. Several metallopolymers were also synthesized. The isolated compounds were characterized by NMR, elemental analyses, and GPC. Photophysical studies have been performed on all the polymers and metallopolymers. Finally, these compounds have been used for the design of electroluminescent devices.