This diploma thesis deals with noncontact temperature measurement using luminescent materials. In the theoretical part of the thesis, luminescent materials were selected on the basis of a literature review with respect to sensitivity and operating temperature range. In the experimental part of the thesis, photoluminescence of CdSe/ZnS and GaAs quantum dots for various temperatures was measured and the relative change of luminescence parameters such as emission peak position, intensity, intensity ratio of two emission peaks, and lifetime of luminescence were determined from the measurements in agreement with expectations according to the literature. Achieving high spatial resolution would be made possible by measuring cathodoluminescence, where the luminescence spectra are obtained with an order of magnitude higher spatial resolution. These measurements and the influence of electron beam on the luminescence quality of selected materials will be subject of further experimental study.

In the main part of this thesis I study the relaxation mechanisms of charge carriers in silicon nanocrystals in SiO2 matrix. One of the potential applications of these structures lies in photovoltaics, specifically in construction of all-silicon tandem solar cells. I studied the dynamics of carriers in these structures by methods of ultrafast spectroscopy which helped to unravel the microscopic behaviour of carriers, their transport, localization etc. Furthermore I investigated the doping of such structures as the technology of doping is crucial for manufacture of pn- junctions which are the core component of solar cells. At the end I delve into the dissipative Jaynes-Cummings model by mathematical modeling and theoretical calculations which describes among others microlasers and as such comes under a field of cavity quantum electrodynamics.

The scientific research on organic luminescent molecules is a broadly diversified field.In the present work, two topics have received special attention: First, room-tem-perature phosphorescence (RTP) in amorphous organic layers, and second, specialapplications of organic LEDs (OLEDs). Since the phosphorescence as a transition between a triplet and a singlet state is notspin conservative, it is natively very slow and is usually overlaid by non-radiativetransitions. Experiments on triplet states are therefore often performed at low tem-peratures. Escaping this limitation, the topic of RTP arises, wherein biluminescenceis a special case. This means that phosphorescence and fluorescence can be observedsimultaneously and special attention is paid to the interaction of the two processes. After a theoretical and methodological introduction, this work transfers an establishedmethod for the determination of the photoluminescence quantum yield (PLQY) tobiluminescent and RTP systems. Among other things, it was shown that interactionsbetween the states must be taken into account in order to obtain correct results.Different physical competences can and must be combined, for example to detect thesole phosphorescent contribution to the PLQY of a biluminescent system. However,there is no literature on the consideration of statistical measurement uncertaintiesduring the PLQY acquisition itself. This gap could be closed by developing a methodthat cleverly exploits the measurement principle to obtain a broad statistical basis fordata analysis with moderate additional experimental effort. This evaluation methodhas its strength especially in the fact that it is independent of the actually investigatedobject and thus has relevance beyond research on organic emitters. The following chapter deals with more basic properties of RTP, analysing a num-ber of molecules that can be interpreted as fragments of the well-known tetra-N-phenylbenzidine (TPB). Using a combination of optical characterization and quan-tum mechanical simulations, the twisted biphenyl-core of TPB has been identified asthe basic molecular building block for efficient radiative triplet-singlet transitions. The systematics coming with a series of similar molecules, was further used to developa numerical fit routine for biluminescent processes. Different numbers of bromineatoms were synthetically attached to TPB, which creates a heavy-atom effect thatenhances spin flips and thus triplet-singlet transitions. Mathematically, the dynamicsof the transition processes can be described with a system of coupled differentialequations. The core elements therein are the transition rates, which reflect the timeconstants of the corresponding processes. Radiative and non-radiative transitions aswell as intermolecular interactions could be quantified that way. The last part of the thesis deals with the physics of OLEDs and the developmentof particular OLED applications. Especially the concept of AC/DC OLEDs is deep-ened, which allows an operation with alternating current (AC) by a combination ofdirect-current (DC) components. The big advantage of this design is the independentcontrollability of two diodes within one light source. This allows, for example, thecontinuous adjustment of the emission colour over a wide range. Further improve-ments such as transparency and improved colour rendering are the results of thiswork. Finally, the AC/DC strategy was transferred to a completely new application,in which spatially different radiation characteristics are developed and exploited.:Abstract List of Publications List of Abbreviations I Fundamentals 1 Introduction 2 Organic Luminophores 2.1 Physical Basics of Organic Molecules 2.1.1 Molecular Orbitals 2.1.2 Spin States of Molecules 2.2 Transitions 2.2.1 Jablonski Diagrams 2.2.2 Singlet-Triplet Transitions 2.3 Non-Linear Processes 2.3.1 Förster and Dexter Transfer 2.3.2 Bimolecular Annihilation Processes 2.3.3 Other Quenching Mechanisms 2.4 Room-Temperature Phosphorescence and Biluminescence 2.5 Rate Equations for Luminescent Molecules 3 Methods and Techniques 3.1 Materials 3.1.1 Materials for Biluminescence and RTP Experiments 3.1.2 OLED Materials 3.1.3 PLQY Reference Samples 3.2 Sample Preparation 3.2.1 Spin Coating 3.2.2 Thermal Evaporation 3.3 Setups for Photoluminescent characterization 3.3.1 Enterprise 3.3.2 Time-Correlated Single Photon Counting 3.3.3 PLQY Setup 3.3.4 Fluoromax 3.4 Setups for OLED characterization 3.4.1 DC Electroluminescence 3.4.2 AC Electroluminescence 3.4.3 Beam-Shaping Profiles 3.4.4 Transparency 3.5 Line Shape Analysis of Emission Spectra II Biluminescence of Organic Molecules 4 Photoluminescence Quantum Yield (PLQY) Measurements 4.1 Measurement and Evaluation Procedure 4.2 Experimental Influences on the Results 4.2.1 Importance of the B Measurement 4.2.2 Calibration of the Setup 4.2.3 Other Systematic Errors 4.3 Data Evaluation 4.3.1 Subtraction of the Background 4.3.2 Choosing the Wavelengths for Evaluation 4.3.3 Statistical Data Analysis 4.3.4 Reabsorption in the Sample 4.4 Application of PLQY Measurements 4.4.1 PLQY Values of Reference Samples 4.4.2 The PLQY of Biluminescent Samples 4.4.3 Negative PLQY and the Influence of Quenching 5 TPB fragments 5.1 Motivation and Scope of the Experiment 5.2 Spectroscopic Characterization 5.3 Discussion of the Results 6 Brominated TPB as Test Case for Rate Equation Fitting 6.1 Scope and Expectations 6.2 The Heavy-Atom Effect 6.3 Estimation of the ISC Rate 6.4 Rate Equation Fitter 6.4.1 Experimental Input parameters 6.4.2 Determination of𝑘rand𝑘nr 6.4.3 Discussion of the Fit Routine 6.4.4 Data Acquisition and Experimental Influences 6.5 PL Characteristics of the BrxTPB-Series 6.6 Fit Curves and Numerical Values 6.7 Discussion 7 Summary of Part II III Organic Light-Emitting Diodes 8 Introduction and Theoretical Background 8.1 OLEDs in the Framework of This Thesis 8.2 Introduction and Recent Advances 8.3 Organic Semiconductors and Light-Emitting Diodes 8.3.1 Charge Carrier Transport 8.3.2 Organic Diode Structure 8.3.3 Luminescent Measures 8.3.4 The Emission Colour 8.3.5 Efficiency Parameters of OLEDs 9 Advances in AC/DC OLEDs 9.1 Transparent and colour-tunable OLEDs 9.2 Real-Time Beam Shaping OLEDs 9.2.1 The Influence of the Cavity Mode 9.2.2 Angularly Confined Emission 9.2.3 Results and Discussion 10 Angular resolved EQE 11 Summary of Part III Appendix A Low Intensity Noise of the Spectrometer B Calculation of the Density of Triplet States C User Manual for Grape C.1 The Figures C.2 Options C.3 Outputs C.4 Internal Data Processing D TPB-Fragments: Line-Shape Analysis E BrxTPB Fit Curves F Side projects Bibliography Acknowledgements / Die wissenschaftliche Forschung an organischen lumineszenten Molekülen ist ein breitgefächertes Themenfeld. In der hier vorliegenden Arbeit fanden besonders zwei The-men Beachtung: zum einen die Raumtemperaturphosphoreszenz (RTP) in amorphenorganischen Schichten, und zum anderen spezielle Anwendungen organischer LEDs(OLEDs). Da die Phosphoreszenz als Übergang zwischen einem Triplett- und einem Sigulettzu-stand nicht spinerhaltend ist, ist er nativ sehr langsam und wird meist von nicht-strahlenden Übergängen überlagert. Häufig finden Experimente zu Triplettzustän-den daher unter sehr niedrigen Temperaturen statt. Diese Einschränkung entgehend,ergibt sich das Themenfeld der RTP, worin die Bilumineszenz ein Spezialfall ist. Dasbedeutet, dass zeitgleich Phosphoreszenz und Fluoreszenz beobachtbar sind und einbesonderes Augenmerk auf dem Wechselspiel der beiden Prozesse liegt. Nach einer theoretischen und methodischen Einführung, wird in der vorliegenden Ar-beit eine etablierte Methode zur Bestimmung der Photolumineszenzeffizienz (PLQY)auf bilumineszente und RTP-Systeme übertragen. Unter anderem zeigte sich hierin,dass besonders Interaktionen zwischen den Zuständen berücksichtigt werden müssen,um korrekte Ergebnisse zu erhalten. Unterschiedliche physikalische Kompetenzenkönnen und müssen kombiniert werden, um zum Beispiel den alleinigen phospho-reszenten Anteil an der PLQY eines biluminszenten Systems zu detektieren. Aller-dings existiert keine Literatur zur Berücksichtigung statistischer Messunsicherheitenwährend der PLQY Detektion. Diese Lücke konnt durch eine entwickelte Methodegeschlossen werden, die das Messprinzip geschickt ausnutzt, um mit moderatem ex-perimentellem Mehraufwand eine breite statistische Basis zur Datenanalyse zu erhal-ten. Diese Auswertemethode hat ihre Stärke besonders darin, dass sie vom eigentlichuntersuchten Objekt unabhängig ist und damit auch Relevanz jenseits der Forschungan organischen Emittern hat. Im anschließenden Kapitel werden grundlegendere Eigenschaften der RTP behandelt,wobei eine Reihe an Molekülen analysiert wird, die als Fragmente des bekannten tetra-N-phenylbenzidine (TPB) interpretiert werden können. Mit einer Kombination ausoptischer Charakterisierung und quantenmechanischen Simulationen konnte der ver-drillte Biphenylkern von TPB als der grundlegende molekulare Baustein für effizientestrahlende Triplett-Singulett-Übergänge identifiziert werden. Die Systematik, die Serien ähnlicher Moleküle mit sich bringen, wurde weiterhingenutzt, um eine numerische Anpassungsroutine für bilumineszente Prozesse zu ent-wickeln. TPB Moleküle wurden synthetisch mit verschiedener Zahl an Bromatomenversehen, was einen Schweratomeffekt erzeugt, der Spinumkehr und damit auch Trip-lett-Singulett-Übergänge verstärkt. Mathematisch kann die Dynamik der Übergangs-prozesse mit einen System gekoppelter Differentialgleichungen beschrieben werden.Die Kernelemente darin die Übergangsraten, die die Zeitkonstanten der entsprechen-den Prozesse widerspiegeln. In der vorliegendenden Arbeit konnten somit strahlendeund nichtstrahlende Übergänge, sowie intermolekulare Wechselwirkungen quantifi-ziert werden. Der letzte Teil der Arbeit befasst sich mit der Physik und der Anwendung von OLEDs.Besonders das Konzept der AC/DC OLEDs wird dabei vertieft, das durch eine Kom-bination aus Gleichstrombauteilen, einen Betrieb mit Wechselstrom ermöglicht. Dergroße Vorteil dieses Aufbaus ist die unabhängige Ansteuerbarkeit zweier Dioden in-nerhalb einer Lichtquelle. Das erlaubt zum Beispiel die stufenlose Einstellung derEmissionsfarbe über einen weiten Bereich. Weitere Verbesserungen wie Transparenzund eine verbesserte Farbwiedergabe sind Ergebnisse dieser Arbeit. Letztlich wurdedie AC/DC Strategie auf einen völlig neuen Anwendungsfall übertragen, in dem räum-lich verschiedene Abstrahlcharakteristiken entwickelt und ausgenutzt werden.:Abstract List of Publications List of Abbreviations I Fundamentals 1 Introduction 2 Organic Luminophores 2.1 Physical Basics of Organic Molecules 2.1.1 Molecular Orbitals 2.1.2 Spin States of Molecules 2.2 Transitions 2.2.1 Jablonski Diagrams 2.2.2 Singlet-Triplet Transitions 2.3 Non-Linear Processes 2.3.1 Förster and Dexter Transfer 2.3.2 Bimolecular Annihilation Processes 2.3.3 Other Quenching Mechanisms 2.4 Room-Temperature Phosphorescence and Biluminescence 2.5 Rate Equations for Luminescent Molecules 3 Methods and Techniques 3.1 Materials 3.1.1 Materials for Biluminescence and RTP Experiments 3.1.2 OLED Materials 3.1.3 PLQY Reference Samples 3.2 Sample Preparation 3.2.1 Spin Coating 3.2.2 Thermal Evaporation 3.3 Setups for Photoluminescent characterization 3.3.1 Enterprise 3.3.2 Time-Correlated Single Photon Counting 3.3.3 PLQY Setup 3.3.4 Fluoromax 3.4 Setups for OLED characterization 3.4.1 DC Electroluminescence 3.4.2 AC Electroluminescence 3.4.3 Beam-Shaping Profiles 3.4.4 Transparency 3.5 Line Shape Analysis of Emission Spectra II Biluminescence of Organic Molecules 4 Photoluminescence Quantum Yield (PLQY) Measurements 4.1 Measurement and Evaluation Procedure 4.2 Experimental Influences on the Results 4.2.1 Importance of the B Measurement 4.2.2 Calibration of the Setup 4.2.3 Other Systematic Errors 4.3 Data Evaluation 4.3.1 Subtraction of the Background 4.3.2 Choosing the Wavelengths for Evaluation 4.3.3 Statistical Data Analysis 4.3.4 Reabsorption in the Sample 4.4 Application of PLQY Measurements 4.4.1 PLQY Values of Reference Samples 4.4.2 The PLQY of Biluminescent Samples 4.4.3 Negative PLQY and the Influence of Quenching 5 TPB fragments 5.1 Motivation and Scope of the Experiment 5.2 Spectroscopic Characterization 5.3 Discussion of the Results 6 Brominated TPB as Test Case for Rate Equation Fitting 6.1 Scope and Expectations 6.2 The Heavy-Atom Effect 6.3 Estimation of the ISC Rate 6.4 Rate Equation Fitter 6.4.1 Experimental Input parameters 6.4.2 Determination of𝑘rand𝑘nr 6.4.3 Discussion of the Fit Routine 6.4.4 Data Acquisition and Experimental Influences 6.5 PL Characteristics of the BrxTPB-Series 6.6 Fit Curves and Numerical Values 6.7 Discussion 7 Summary of Part II III Organic Light-Emitting Diodes 8 Introduction and Theoretical Background 8.1 OLEDs in the Framework of This Thesis 8.2 Introduction and Recent Advances 8.3 Organic Semiconductors and Light-Emitting Diodes 8.3.1 Charge Carrier Transport 8.3.2 Organic Diode Structure 8.3.3 Luminescent Measures 8.3.4 The Emission Colour 8.3.5 Efficiency Parameters of OLEDs 9 Advances in AC/DC OLEDs 9.1 Transparent and colour-tunable OLEDs 9.2 Real-Time Beam Shaping OLEDs 9.2.1 The Influence of the Cavity Mode 9.2.2 Angularly Confined Emission 9.2.3 Results and Discussion 10 Angular resolved EQE 11 Summary of Part III Appendix A Low Intensity Noise of the Spectrometer B Calculation of the Density of Triplet States C User Manual for Grape C.1 The Figures C.2 Options C.3 Outputs C.4 Internal Data Processing D TPB-Fragments: Line-Shape Analysis E BrxTPB Fit Curves F Side projects Bibliography Acknowledgements

Sn2P2S6 is ferroelectric at room temperature. It is of technological interest in a variety of applications such as pyroelectric motion detectors and the photorefractive effect. Until now the defect structure and the light-induced charge transfer processes in this material have not been subject of a detailed investigation. The main part of this thesis describes and interprets data of electron paramagnetic resonance (EPR), optical absorption spectroscopy and their combination at 10 K to unravel the light-induced sensitization and charge transfer paths. In the photosensitized crystal at excitation with 1.5 eV a hole is transferred from a previously generated Sn3(plus) site to another inequivalent site of the ferroelectric phase. For higher excitation energies another hole present as Fe3(plus) is transferred to S2- creating S-. Optical absorption spectroscopy at room temperature indicates the validity of this model for evelated temperature below the Curie-temperature as well. It is consistent with both our interpretation of EPR spectra and the observation of photoinduced persistent conductivity that electronic bipolarons are the negative charge carriers. An additional chapter interprets a manifestation of pyroelectric luminescence already reported in other pyroelectric materials in terms of an internal Poole-Frenkel-effect induced by the pyroelectric field under changing temperature. The numerical simulation based on published material parameters is in good agreement with the experimental data for both heating and cooling.

Optical properties of bismuth borate are measured for the composition range x Bi2O3 (1-x) B2O3, 0.25 < x < 0.65. The refractive indices increase as the bismuth content is increasing. Also the ultraviolet absorption edge was shown to shift to longer wavelengths. From these measurements a generalized Sellmeier formula was derived. Applying heat treatments to the prepared bismuth borate glasses in order to obtain glass ceramics leads in most cases to surface nucleation. It was proved that dopants increase the number of nucleating sites on the surfaces. On erbium-doped samples absorption and luminescence measurements were made. The Judd-Ofelt analysis revealed comparably high Judd-Ofelt coefficients. All coefficients were shown to decrease as the Bi2O3 content increases. The luminescence at 1550 nm reveals a broad and flat band which is narrowing with the increase in Bi2O3 content. The green upconversion was observed and the temporal behavior of the emission at 550 nm was investigated. The absorption and emission spectra of chromium-doped bismuth borate glasses were measured. On surface crystallized glasses, for x = 0.5 Bi2O3 and high chromium content, luminescence of chromate (CrO2-4) ion doped BiBO3 microcrystals was observed. Strontium barium niobate microcrystals embedded in strontium barium borate matrix were obtained by spontaneous nucleation in the melt and rapid quenching. Optical properties of Pb2B5O9Br based glass were also investigated. The heat treatment applied leads to the formation of small nanocrystals inside the glass.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19406号 / 工博第4122号 / 新制||工||1635(附属図書館) / 32431 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 中條 善樹, 教授 澤本 光男, 教授 赤木 和夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The G-center has recently been identified as the first deterministic single-photon punctual emitter isolated in silicon. This discovery is of great interest for largescale quantum technologies, due to the abilities of silicon in terms of integration and scalability. However, the spontaneous emission rate of the G-center still needs to be controlled in order to engineer a useful Single-Photon Source. This could be achieved by incorporating a single G-center in resonant microcavities to benefit from the Purcell effect. As a first step in this direction, we have studied in this project micro-cavities containing an ensemble of G-centers, more precisely Si micro-disks and micro-rings on oxide, with several objectives: the evaluation of the quality factor of micro-cavities containing G-centers, the demonstration of an optical activity of G-centers after the processing of the silicon micro-structures, and the evaluation of their potential as gain medium for integrated microlasers on SOI. The observation of bright photoluminescence from G-centers and of resonant cavity modes with Q’s in the few thousands range confirms the compatibility of G-centers with standard silicon processing steps, and is encouraging for future quantum optics experiments on isolated G centers in micro-cavities. Our results also tend to show that gain may be available in the material, but residual absorption still needs to be decreased to achieve lasing. / G-center har nyligen identifierats som den första determinitiska ponctual enfoton källen isolerad i kisel. Denna upptäckt är av stort intresse för kvantteknologier p.g.a. kisels förmåga gällande integration och skalbarhet. G-centers spontana rekombinationshastighet behöver dock kontrolleras för att skapa en användbar enfoton källa. Det kan göras genom Purcell-effekten i en optisk resonator. Som ett första steg har vi studerat mikroresonatorer som innehåller G-center i det presenterade projektet, med flera mål: utvärdering av kvalitetsfaktor för mikroresonatorer som innehåller G-center, demonstration av optisk aktivitet av G-center efter tillverkning av kiselmikrostrukturer, och utvärdering av deras potential för integrerade mikrolaser på SOI. Observation av stark fotoluminescens av G-center och resonatormoder med stor-Q bekräftar kompatibilitet mellan G-center och vanliga steg för bearbetning av kisel, och är uppmuntrande för framtida Kvantum Optik experimenter med isolerade G-center i mikroresonatorer. Resultaten visar att ljusförstärkning troligtvis börjar, men absorption av andra defekter måste minskas för att uppnå laserregim.

We report on the observation of lasing in cuprous iodide (CuI) microwires. A vapor-phase transport growth procedure was used to synthesize CuI microwires with low defect concentration. The crystal structure of single microwires was determined to be of zincblende-type. The high optical quality of single microwires is indicated by the observed series of excitonic emission lines as well as by the formation of gain under optical excitation. Lasing of triangular whispering-gallery modes in single microwires is demonstrated for fs- and ns-excitation from cryogenic temperatures up to 200 K. Timeresolved micro-photoluminescence studies reveal the dynamics of the laser process on the time scale of several picoseconds.

<p>Solid-state (SS) luminescent materials are an important class of materials in a myriad of technological applications including light-emitting devices (LEDs) and displays, SS lasers, sensors, imaging agents, etc. Unfortunately, the design of efficient SS emitters is often plagued by sensitivity to environment/matrix (e.g. aggregation-induced quenching, AIQ), competing non-radiative relaxation pathways, and complicated emission mechanisms that are difficult to systematically study and tune. Copper-based systems have been proven to be good candidates for SS emissive materials due to their low-cost, high synthetic variation and well-defined features. Examples of copper-cluster systems, specifically, have been shown to be highly stable, exhibit high photoluminescent quantum yields (ΦPL), and are often relatively insensitive to environmental changes. However, many of these systems are complicated in nature, and often evoke additional relaxation pathways. To mitigate these issues, tetranuclear Cu(I)-pyrazolate complexes have been made which exhibit high ΦPL, matrix insensitivity and proceed through one major radiative emission pathway: cluster-centered based phosphorescence (3CC). The pyrazoles are highly tunable, and by increasing the size of the ligand substituents (H, F, Cl/Me/Br), a rigidochromic effect is observed, causing a significant blue-shift in their photoluminescence, making these viable materials for organic LEDs (OLEDs), especially in the deep-blue region. Furthermore, by increasing the chain length of the ligand substituent (e.g., Me → Et), another material which exhibits stimuli-responsive luminochromism in response to solvent vapor or heat can be achieved. This material exhibits blue ↔ green rigidochromic luminescence in response to stimuli via isomerization of the ethyl units from exo ↔ endo resulting in additional steric effects that effectively prevent rigidification of the Cu4 cluster. This additional phenomenon opens the door for further exploration of Cu(I)-pyrazolate complexes for stimuli-responsive luminescent materials (SRLMs) applications.</p>

A total of 17 samples were collected for OSL dating from a Swift Creek archaeological site, known as Harrison Ring, which lies on the Tyndall Air force peninsula in northwest Florida. High-resolution vertical sampling conducted at 10 cm intervals from the surface was performed in order to determine the timing of occupation at the site, and to look for patterns in radiation dosimetry and post-depositional disturbance that can compromise OSL results. We find OSL ages determined using both 0.5 mm aliquots and single grains at the archaeological levels (approximately 1751 ± 339 years ago) to be consistent with the timing of early Swift Creek cultures on the Florida Gulf Coast. The ages we report are both consistent with radiocarbon dates taken at Harrison Ring, and those taken at other Swift Creek sites on the Gulf Coast. In general, we find OSL equivalent doses that show high overdispersion and skewness that we attribute to beta-microdosimetry and possible bioturbation in the profiles. We also present results from a test with a novel dosimetric technique employing Al2O3:C chips. By using Al2O3:C dosimeters, we find that large variability in beta dose rates exist in the sedimentary profile at Harrison Ring. By testing a combination of dosimetric techniques in a site with a well-constrained age, we find that the best agreement with independent age control exists when calculating ages using a beta dose rate from NAA/DNC and gamma dose rate from Al2O3:C dosimetry. / Thesis / Master of Science (MSc)