Because of its potential application for flat panel displays, solid-state lighting and 1.5 µm emitter for fiber optical communications, organic light-emitting diodes (OLEDs) have been intensively researched. One of the major problems with current OLED technology relates to inefficient electron injection at the cathode interface, which causes high driving voltage and poor device stability. Making a low resistance cathode contact for electron injection is critical to device performance. This work mainly focuses on cathode interface design and engineering. The Ohmic contact using a structure of C60/LiF/Al has been developed in electron only devices. It is found that application of the C60/LiF/Al contact to Alq based OLEDs leads to a dramatic reduction in driving voltages, a significant improvement in power efficiency, and a much slower aging process. A new cathode structure based on metal-organic-metal (MOM) tri-layer films has been developed. It is found that MOM cathodes reduce reflection by deconstructive optical interference from two metal films. The absolute reflectance from the MOM tri-layer films can be reduced to as low as 7% in the visible light spectrum. In actual working devices, the reflectance can be reduced from ~80% to ~ 20%. MOM cathodes provide a potential low-cost solution for high contrast full-color OLED displays. Low voltage Erq based OLEDs at 1.5 µm emission have been developed. The Erq/Ag cathode interface has been found to be efficient for electron injection. Dramatic improvement in driving voltage and power efficiency has been realized by implementing Bphen and C60 into Erq devices as an electron transport layer. Integration of Erq devices on Si wafers has also been demonstrated.

Phosphorescent organic light emitting diodes (PHOLEDs) based on efficient electrophosphorescent dopant, platinum(II)-pyridyltriazolate complex, bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) have been studied and improved with respect to power efficiency, external efficiency, chromacity and efficiency roll-off. By studying the electrical and optical behavior of the doped devices and functionality of the various constituent layers, devices with a maximum EQE of 20.8±0.2 % and power efficiency of 45.1±0.9 lm/W (77lm/W with luminaries) have been engineered. This improvement compares to devices whose emission initially could only be detected by a photomultiplier tube in a darkened environment. These devices consisted of a 65 % bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) doped into 4,4'-bis(carbazol-9-yl)triphenylamine (CBP) an EML layer, a hole transporting layer/electron blocker of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), an electron transport layer of 1,3,5-tris(phenyl-2-benzimidazolyl)-benzene (TPBI), and a LiF/Al cathode. These devices show the acceptable range for warm white light quadrants and qualify to be called "warm white" even w/o adding another emissive layer. Dual EML devices composed of neat Pt(ptp)2 films emitting orange and CBP: Pt(ptp)2 film emitting blue-green produced a color rendering index (CRI) of 59 and color coordinates (CIE) of (0.47,0.49) at 1000Cd/m² with power efficiency of 12.6±0.2 lm/W and EQE of 10.8±0.2 %. Devices with two blue fluorescent emission layers as singlet filters and one broad yellow emission layer from CBP: Pt(ptp)2 displayed a CRI of 78 and CIE of (0.28,0.31) at 100Cd/m² with maximum power efficiency of 6.7±0.3 lm/W and EQE of 5.7±0.2 %.

New red emitting phosphors, based on the double tungstate/molybdates, were discovered. Some were able to retain their luminous efficacy after substituting Y3+ for Eu3+, reducing the cost of the phosphor. This substitution was attempted for existing commercial red emitting phosphors and proved unsuccessful. Another set of phosphors based on these lattices were discovered and the emitted luminous efficacy was 140% greater than other reported Eu3+ phosphors. The best of these was Na2WO4MoO4Eu0.44Al1.34Sm0.011. The integration of phosphors to the lighting application was also studied, including improvements in light extraction for existing phosphors. ACEL panels are currently applied to many applications and were briefly examined. The more recent OLED technology was investigated and comparisons can be drawn with the ACEL panels. LEDs were also a focus of the work with a new method developed for remote application of phosphors to LEDs, based on a dome shaped encapsulant, and this was adopted commercially by a high brightness LED manufacturer. The studies on the phosphors reported herein were aimed at integrating these into commercial applications. Although this was not achieved as brightness and particles size were problematic, if it is demonstrated that further development of the synthetic methods produce phosphors with suitable attributes, this may lead to the integration in applications.

The synchronization of coupled semiconductor lasers with delay is investigated by numerical simulations of the nonlinear dynamic models complemented by a stability analysis of the linearized system. The equations used in the dissertation are based on the well known "Lang-Kobayashi" model modified to include unidirectional and bidirectional coupling. Stability diagrams are calculated and supplemented by numerically integrated time series. Synchronization is determined and quantified by computing the cross-correlation function. It is found that synchronized states are achievable for a wide range of coupling constants and delay times. These findings have implications for experiment and technological applications, notably in cryptography. / by Michael S. London. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

O presente trabalho teve como objetivo o estudo da aplicação de um novo polímero, o poli [2,7(9,9dioctilfluoreno)alt1,4fluorfenileno], dopado com o 5,6,11,12tetrafenilnaftaceno (rubreno), como camada ativa de diodos emissores de luz poliméricos, os PLEDs. O polímero semicondutor polifluoreno fluorado (PFF), da classe dos polifluorenos, foi sintetizado por meio da reação de acoplamento via rota de Suzuki, onde ao final da síntese apresentou um rendimento de processo de 95%. O polímero foi caracterizado por diversas técnicas analíticas a fim de comprovar a formação da estrutura molecular prevista. A análise de cromatografia de permeação em gel (GPC) indicou valores de massa molar numérica média (Mn) e massa molar ponderal média (Mw) de 4230 g/mol e 21490 g/mol, respectivamente. As análises térmicas de calorimetria diferencial exploratória (DSC) e análise termogravimétrica (TGA) indicaram a presença de um pico de fusão a 145°C, e início de degradação em torno de 200°C, respectivamente. As análises espectroscópicas no infravermelho (IR), espectrometria de energia dispersiva de raios X (EDX) e ressonância magnética nuclear de hidrogênio (1HRMN) comprovaram a presença de anéis aromáticos, grupos CH2, CH3 e hidrocarbonetos fluorados na estrutura do polímero, enquanto a difração de raios X (DRX) indicou 9% de grau de cristalinidade, tratando-se, portanto, de um polímero semicristalino, conforme previamente indicado pela análise DSC. O poli[2,7(9,9dioctilfluoreno)alt1,4fluorfenileno] foi dopado com o 5,6,11,12tetrafenilnaftaceno (rubreno) em diferentes proporções mássicas, a fim de avaliar a interação entre ambos os materiais por meio das respostas obtidas pelos sistemas dopados e não-dopados através das caracterizações por espectroscopia de absorção e fotoluminescência no UV-Visível, realizadas nas amostras em solução e em filme. Os materiais puros, em solução, apresentam picos de absorção em 360 nm e 300 nm e de emissão em 410 nm e 560 nm, para o polímero e para o rubreno, respectivamente. O rubreno apresentou pico de emissão de menor intensidade em torno de 400 nm quando excitado em 360 nm. Os sistemas foram dopados nas seguintes proporções em porcentagem de massa de polímero:rubreno, 100:0, 98:2, 95:5, 90:10, 80:20, 50:50, e quando analisados em solução e excitados em 300 nm, apresentam fluorescência em duas regiões diferentes do espectro eletromagnético, em 410 nm e em 560 nm, ou seja, tanto o polímero quanto o rubreno apresentam resposta emissiva, cada um em sua região característica do espectro eletromagnético. Já quando excitados em 360 nm apresentaram picos de emissão somente em 410 nm, região característica do polímero, porém os espectros das soluções dopadas apresentaram aumento da intensidade do pico de emissão em 410 nm, fato este atribuído à contribuição do rubreno, que quando excitado em 360 nm apresenta uma pequena emissão em torno de 410 nm. Os materiais dopados nas mesmas proporções, quando analisados em filme e excitados em 360 nm, apresentaram bandas de emissão, na faixa entre 410 nm e 450 nm e outra com máxima em 560 nm, diferente do observado nas amostras dopadas em solução e excitadas no mesmo comprimento de onda. Esta alteração no comportamento das amostras pode ser atribuída à maior proximidade entre as moléculas quando se encontram na forma de filme, melhorando a interação e a transferência de energia entre os cromóforos. Os sistemas também foram estudados quanto ao seu comportamento eletroluminescente, para isso foram fabricados dispositivos eletroluminescentes nas seguintes proporções em porcentagem de massa de polímero:rubreno, 100:0, 95:5, 90:10, 80:20, 50:50. Na confecção dos dispositivos utilizou-se o poli(3,4etilenodioxitiofeno) dopado com poli(4sulfonato de estireno), conhecido como PEDOT:PSS, como camada transportadora de lacunas (HTL Hole Transport Layers) e o alumínio como cátodo responsável pela injeção de elétrons. Foram realizadas caracterizações elétricas e ópticas dos dispositivos, por meio do levantamento da curva de densidade de corrente em função da tensão, dos espectros de eletroluminescência, das coordenadas de cromaticidade e pela caracterização visual através de fotografias. Os dispositivos preparados com o polímero puro, quando caracterizados eletricamente, apresentaram valores de tensão de limiar e luminância de 14 V e 18,7 cd/m2, respectivamente, enquanto os dispositivos dopados apresentaram tensão de limiar variando entre 14 V e 7 V, e luminância entre 125 e 278 cd/m2, aproximadamente. Observou-se ainda que com o aumento da concentração de rubreno na camada ativa houve um aumento da luminância, atingindo o máximo em menores tensões. Todos os dispositivos apresentam resposta elétrica típica de diodos. A intensidade luminosa dos dispositivos se intensificou à medida que a densidade de corrente aumentou, atingindo um máximo em tensões entre 10 V e 20 V, aproximadamente, seguidas de uma redução. Os espectros colhidos dos dispositivos poliméricos emissores de luz (PLEDs-Polymer Light Emitting Diode) mostram que os dispositivos preparados a partir do polímero puro apresentaram baixa intensidade de emissão quando comparados aos dispositivos dopados. A dopagem intensificou os picos de emissão em 560 nm em aproximadamente 20 vezes. / The present work aimed to study the application of a new polymer, poly[2,7-(9,9-dioctylfluorene)-alt-1,4-fluorophenylene], doped with 5,6,11,12-tetraphenylnaphthacene (rubrene) as the active layer of polymer light emitting diodes, the PLEDs. The semiconductor fluorinated polyfluorene (PFF) was synthesized by Suzuki coupling reaction, with a yield of 95%. The polymer was characterized by various analytical techniques in order to confirm the formation of the expected molecular structure. The analysis by gel permeation chromatography (GPC) indicated numerical average molar mass (Mn) and ponderal average molar mass (Mw) of 4230 g/mol and 21490 g/mol, respectively. Thermal analysis of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated the presence of a melting peak at 145°C and the beginning of degradation around 200°C, respectively. The infrared spectroscopy (IR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction spectrometry (XRD), hydrogen nuclear magnetic resonance (1HNMR) confirmed the presence of aromatic rings, CH2 and CH3 groups and fluorinated hydrocarbons in the polymer structure, while the X-ray diffractometry (XRD) showed a degree of crystallinity of 9%, therefore, a semicrystalline polymer, as previously indicated by DSC analysis. The poly[2,7-(9,9-dioctylfluorene)-alt-1,4-fluorphenylene] was doped with 5,6,11,12-tetraphenylnaphthacene (rubrene) at different mass ratios in order to evaluate the interaction between both materials by means of responses for systems doped and non- doped. The systems thus formed were characterized by absorption and photoluminescence spectroscopy in the UV-Visible region and both their solutions in chloroform as well as the solid films were studied. The neat materials, polymer and rubrene, in solution showed absorption peaks at 360 nm and 300 nm and emission at 410 nm and 560 nm, respectively. An emission peak of lower intensity at around 400 nm after excitation at 360 nm was also observed for rubrene. The systems were doped in the following proportions in percent of the polymer:rubrene , 100:0 , 98:2 , 95:5 , 90:10 , 80:20 , 50:50 , and fluorescence spectroscopy were carried out in solution after excitation at 300 nm, resulting in two different regions of emission, at 410 nm and 560 nm, demonstrating independent and characteristic spectra. However, when excited at 360 nm, only emission peaks at 410 nm region, characteristic of the polymer, was observed, furthermore, the spectra of the doped solutions showed increased emission intensity, due to the contribution of rubrene, as a small emission around 410 nm, when excited at 360 nm, has been observed. Films of the doped systems at the same proportions, excited at 360 nm, showed emission bands in the range 410 - 450 nm and, at the same time, another band with maximum at 560 nm. This behavior is different from that observed for the same samples in solution under an equal condition of analysis. This behavior can be explained by the greater proximity between the molecules when they are in the solid state, increasing the segmental interactions and energy transfer between chromophores. The electroluminescence was also analysed by building devices having an active layer of the polymer:rubrene at different mass ratio, 100:0 , 95:5 , 90:10 , 80:20 , 50:50. The devices were built using poly(3,4-ethylenedioxythiophene) doped with poly(4-styrene sulfonate), PEDOT:PSS, as a hole transporting layer (HTL) and aluminum as the cathode. The devices having neat polymer as the active layer presented luminance of 14 cd/m2 at 18.7 V, while the devices for the doped active layers presented threshold voltage ranging from 14 V to 7 V, and luminance between 125 and 278 cd/m2, approximately. It was observed that by increasing the concentration of rubrene in the active layer, increased luminance was reached at lower voltages. All devices feature typical electrical response of diodes. The luminous intensity of the device is intensified as the current density increased, reaching a maximum at voltages between 10 V and 20 V. The electroluminescence spectra showed lower emission intensity for the neat polymer compared to those observed for the doped. The emission intensity at 560 nm increased approximately 20 times after doping.

Neste trabalho é apresentado um estudo comparativo da resposta de diodos de Si para dosimetria de radiação gama. Os diodos investigados, crescidos pelas técnicas de fusão zonal (Fz) e Czchocralski magnético (MCz), foram processados no Instituto de Física da Universidade de Helsinki no âmbito das pesquisas e desenvolvimento de dispositivos de Si resistentes a danos de radiação segundo a colaboração RD50 do CERN (European Organization for Nuclear Research). Para estudar a resposta dosimétrica dos diodos, eles foram acoplados diretamente no modo fotovoltaico na entrada de um eletrômetro digital para medir o sinal de fotocorrente devido a incidência de raios gama provenientes de uma fonte de 60Co (Gammacell 220). O parâmetro dosimétrico usado para estudar a resposta destes dispositivos foi a carga, obtida pela integração do sinal de corrente pelo tempo de exposição, em função da dose absorvida. Estudos da influência dos procedimentos de pré-irradiação na sensibilidade e estabilidade destes diodos mostraram que a sensibilidade decresce com a dose total absorvida mas depois de uma pré-irradiação de cerca de 873 kGy, eles se tornaram mais estáveis. Efeitos dos danos de radiação eventualmente produzidos nos diodos foram monitorados mediante medidas dinâmicas de corrente e de capacitância depois de cada etapa de irradiação. Ambas as amostras exibiram boa reprodutibilidade de resposta, 2,21% (Fz) e 2,94% (MCz), obtida com 13 medidas consecutivas de 15 kGy comparadas com a equivalente dose de 195 kGy absorvida em uma única etapa de irradiação. É importante notar que estes resultados são melhores do que aqueles obtidos com dosímetros de rotina de polimetilmetacrilato (PMMA) usados em processamento por radiação. / In this work it is presented the comparative study of Si diodes response for gamma radiation dosimetry. The diodes investigated, grown by float zone (Fz) and magnetic Czchcralski (MCz) techniques, were processed at the Physics Institute of Helsinki University in the framework of the research and development of rad-hard silicon devices. To study the dosimetric response of these diodes they were connected in the photovoltaic mode to the input of a digital electrometer to measure the photocurrent signal due to the incidence of gamma-rays from a 60Co source (Gammacell 220). The dosimetric parameter utilized to study the response of these devices was the charge, obtained trough the integration of the current signals, as a function of the absorbed dose. Studies of the influence of the pre-irradiation procedures on both sensivity and stability of these diodes showed that the sensitivity decreased with the total absorbed dose but after a preirradiation of about 873 kGy they became more stable. Radiation damage effects eventually produced in the devices were monitored trough dynamic current and capacitance measurements after each irradiation step. Both samples also exhibited good response reproducibility, 2,21% (Fz) and 2,94% (MCz), obtained with 13 consecutive measurements of 15 kGy compared with the equivalent 195 kGy absorbed dose in one step of irradiation. It is important to note that these results are better than those obtained with routine polimetylmetacrilate (PMMA) dosimeters used in radiation processing dosimetry .

No presente trabalho foi estudada a resposta de diodos epitaxiais (EPI) e fusão zonal (FZ) como dosímetros on-line em tratamentos radioterápicos com feixe de fótons na faixa de megavoltagem (diodo tipo EPI)e ortovoltagem (diodos tipo EPI e FZ). Para serem usados como dosímetros os diodos foram encapsulados em sondas de polimetilmetacrilato preto (PMMA). Para as medidas da fotocorrente os dispositivos foram conectados a um eletrômetro Keithley® 6517B no modo fotovoltaico. As irradiações foram feitas com feixes de fótons de 6 e 18 MV (acelerador Siemens Primus®),6 e 15 MV (acelerador Novalis TX®) e 10, 25, 30 e 50 kV de um equipamento de Radiação X Pantak/Seifert. Nas medidas com o acelerador Siemens Primus® os diodos foram posicionados entre placas de PMMA a uma profundidade de 10,0 cm e com o acelerador Novalis TX® mantidos entre placas de água sólida a uma profundidade de 5cm. Em ambos os casos, os diodos foram centralizados em campos de radiação de 10 × 10 cm2, com distância fonte superfície (DFS) mantida fixa em 100 cm. Para as medidas com os feixes de fótons deortovoltagem os diodos foram posicionados a 50 cm do tubo em um campo de radiação circular de 8 cm de diâmetro. A linearidade com a taxa de dose foi avaliada para as energias de 6 e 15MV do acelerador Novalis TX® variando-se a taxa de dose de 100 a 600 unidades monitoras por minuto e para o feixe de 50 kV variando-se a corrente do tubo de 2 a 20 mA. Todos os dispositivos apresentaram respostas lineares com a taxa de dose e dentro das incertezas, independência da carga com a mesma. Os sinais de corrente mostraram boa repetibilidade, caracterizada por coeficientes de variação em corrente (CV) inferiores a 1,14%(megavoltagem) e 0,15%(ortovoltagem) e em carga menores que 1,84% (megavoltagem) e 1,67% (ortovoltagem). Foram obtidas curvas dose-resposta lineares com coeficientes de correlação linear melhores que 0,9999 para todos os diodos. / In the current work it was studied the performance of epitaxial (EPI) and float zone (FZ) silicon diodes as on-line dosimeters for megavoltage (EPI diode) and orthovoltage (EPI and FZ diode) photon beam radiotherapy. In order to be used as dosimeters the diodes were enclosed in black polymethylmethacrylate (PMMA) probes. The devices were then connected, on photovoltaic mode, to an electrometer Keithley® 6517B to allow measurements of the photocurrent. The irradiations were performed with 6 and 18 MV photon beams (Siemens Primus® linear accelerator), 6 and 15 MV (Novalis TX®) and 10, 25, 30 and 50 kV of a Pantak / Seifert X ray radiation device. During the measurements with the Siemens Primus® the diodes were held between PMMA plates placed at 10.0 cm depth. When using Novalis TX® the devices were held between solid water plates placed at 50 cm depth. In both casesthe diodes were centered in a radiation field of 10 x 10 cm2, with the source-to-surface distance (SSD) kept at 100 cm. In measurements with orthovoltage photon beams the diodes were placed 50.0 cm from the tube in a radiation field of 8 cm diameter. The dose-rate dependency was studied for 6 and 15 MV (varying the dose-rate from 100 to 600 monitor units per minute) and for the 50 kV beam by varying the current tube from 2 to 20 mA. All devices showed linear response with dose rate and, within uncertainties the charge collected is independent of dose rate. The current signals induced showed good instantaneous repeatability of the diodes, characterized by coefficients of variation of current (CV) smaller than 1.14% (megavoltage beams) and 0.15% for orthovoltage beams and coefficients of variation of charge (CV) smaller than 1.84% (megavoltage beams) and 1.67% (orthovoltage beams). The doseresponse curves were quite linear with linear correlation coefficients better than 0.9999 for all diodes.

Li, Kwan Ho = 多體量子系統問題 / 李君豪. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves [243]-246). / Text in English; abstracts in English and Chinese. / Li, Kwan Ho = Duo ti liang zi xi tong wen ti / Li Junhao. / Abstract --- p.i / Acknowledgment --- p.iv / Chapter I --- Computational Quantum Mechanics and Its Applications --- p.1 / Chapter 1 --- Theoretical Methodology of Electronic Structures --- p.2 / Chapter 1.1 --- The Schrodinger Equation --- p.3 / Chapter 1.2 --- Molecular Hamiltonian and Born-Oppenheimer Approximation --- p.4 / Chapter 1.3 --- The Variational Method --- p.7 / Chapter 1.3.1 --- Rayleigh-Ritz Variation Principle --- p.7 / Chapter 1.3.2 --- Linear Variation --- p.8 / Chapter 1.4 --- Many-Electron Wavfunction --- p.9 / Chapter 1.4.1 --- Hartree-product Wavefunction --- p.9 / Chapter 1.4.2 --- Slater Determinant and the Pauli Exclusion Principle --- p.11 / Chapter 1.5 --- The Expectation Value of Total Electronic Energy --- p.13 / Chapter 1.6 --- Derivation of the Hartree-Fock Equations --- p.16 / Chapter 1.7 --- Orbital Energies and the SCF Total Electronic Energy --- p.19 / Chapter 1.8 --- Koopmans' Theorem --- p.20 / Chapter 1.9 --- The LCAO expansion and Self-Consistent Field Calculation --- p.22 / Chapter 1.10 --- AO Basis Sets --- p.23 / Chapter 1.10.1 --- Slater-Type Orbitals --- p.24 / Chapter 1.10.2 --- Gaussian Functions --- p.24 / Chapter 1.11 --- Hartree-Fock Limit --- p.25 / Chapter 1.12 --- Electron Correlation --- p.26 / Chapter 1.12.1 --- Weakness in the Single Determinantal Wavefunction --- p.26 / Chapter 1.12.2 --- Configuration Interaction --- p.26 / Chapter 1.13 --- Density Functional Theory --- p.27 / Chapter 1.13.1 --- Early approximations --- p.28 / Chapter 1.13.2 --- Hohenberg-Kohn Theorems --- p.31 / Chapter 1.13.3 --- Kohn-Sham (KS) Method --- p.33 / Chapter 1.13.4 --- Exchange-Correlation Energy Functional and B3LYP --- p.36 / Chapter 2 --- Theoretical Investigation of Oxadiazole-Triphenylamine Based Compounds --- p.40 / Chapter 2.1 --- Organic Light Emitting Diode and Oxadiazole-Triphenylamine Based Com- pounds --- p.40 / Chapter 2.2 --- Methodology --- p.42 / Chapter 2.2.1 --- Theoretical Methodology --- p.42 / Chapter 2.2.2 --- Computational Methodology --- p.46 / Chapter 2.3 --- Computational Results --- p.47 / Chapter 2.3.1 --- Molecular Structure --- p.47 / Chapter 2.3.2 --- Electronic Structure --- p.79 / Chapter 2.4 --- Absorption and Emission Energy --- p.94 / Chapter 2.5 --- Reorganization Energy and Mobility --- p.95 / Chapter 2.6 --- Summary --- p.99 / Chapter 3 --- The Transport Properties of Oligoacenes --- p.102 / Chapter 3.1 --- Introduction --- p.102 / Chapter 3.2 --- Computational Details --- p.103 / Chapter 3.3 --- Results and Discussions --- p.103 / Chapter 3.3.1 --- Molecular Configuration --- p.103 / Chapter 3.3.2 --- Reorganization Energy --- p.106 / Chapter 3.3.3 --- Coupling Matrix Element --- p.107 / Chapter 3.4 --- Conclusion --- p.133 / Chapter 4 --- The Transport Properties in Rubrene Thin Film and Crystal --- p.135 / Chapter 4.1 --- Introduction --- p.135 / Chapter 4.2 --- Computational Details --- p.137 / Chapter 4.3 --- Results and Discussions --- p.137 / Chapter 4.3.1 --- Molecular Structure --- p.137 / Chapter 4.3.2 --- Frontier Orbitals --- p.144 / Chapter 4.3.3 --- Reorganization Energy --- p.147 / Chapter 4.3.4 --- Coupling Matrix Element and Mobility --- p.147 / Chapter 4.4 --- Conclusion --- p.175 / Chapter II --- Analytical Studies of Anisotropic Spin-1/2 Heisenberg Anti-ferromagnetic Linear Chains --- p.177 / Chapter 5 --- Coupled-Cluster Approximation for Two Anisotropic Spin-1/2 Heisenberg Antiferromagnetic Linear Chains with Inter-chain Anisotropic Ferromagnetic Interaction --- p.178 / Chapter 5.1 --- Introduction --- p.178 / Chapter 5.2 --- Approximation in the Coupled-Cluster Method --- p.179 / Chapter 5.3 --- Anisotropic spin-1/2 Heisenberg Antiferromagnetic Model in One Dimension --- p.183 / Chapter 5.3.1 --- The Zeroth Level --- p.185 / Chapter 5.3.2 --- The First Level --- p.186 / Chapter 5.3.3 --- The Second Level --- p.189 / Chapter 5.4 --- Two Anisotropic Spin-1/2 Heisenberg Antiferromagnetic Linear Chains with Inter-chain Anisotropic Ferromagnetic Interaction --- p.198 / Chapter 5.4.1 --- The Zeroth Level --- p.199 / Chapter 5.4.2 --- The First Level --- p.201 / Chapter 5.4.3 --- The Second Level --- p.206 / Chapter 5.5 --- Conclusion --- p.242 / Bibliography --- p.243

This research project consists of a critical analysis of the role of intellectual property amongst other factors in the successful commercial development at the Cavendish Laboratory of optoelectronic light emitting diode display devices based on novel organic semiconductor materials. It begins by giving the background to the quantum mechanical properties upon which the technology is based, followed by a discussion of the path of innovation, describing the interaction between the different socioeconomic factors that influence this path. It then draws an analogy with the development of an analogous technology - inorganic semiconductors - to signpost the factors that may affect the developmental history of the technology. This is followed by an analysis of a chronology derived initially from patents downloaded from the World Patents Database of the European Patent Office to showcase the technology's development steps, and to study the patenting strategy of Cambridge Display Technology (CDT) - the company that was set up to commercialise the novel technology - through a patent trends analysis. From that, the major socioeconomic factors critical to the technology's development are analysed, followed by a test and extension of an existing Black Box mathematical model for studying the dynamics of innovation that is based on the interaction of those factors. Finally, through a patent citation analysis, CDT's commercial strategy for the technology is shown as being based on its patents portfolio to build an extensive licensing programme that pooled major academic, industry and commercial partners for the furtherance of the technology. This later evolved into a new ecosystem for the innovation, of which CDT occupied a central and indispensable position.

No description available.