A controllable self-assembly strategy of positively charged polycyclic aromatic hydrocarbons (PCPAH) towards the formation of rectangle sheets and ribbon-like nanostructures has been achieved by choosing divalent anions with different sizes. In contrast, only rod-like nanostructures are obtained from PCPAH with univalent anions. It is revealed that the divalent anions play a key role in guiding the packing of PCPAH, which provides an unprecedented route to fabricate two-dimensional nanostructures.

Im Rahmen der vorliegenden Arbeit wurde eine neuartige Lidartechnik in ein leistungsstarkes Lidar-System implementiert. Mit Hilfe des realisierten Aufbaus wurden Aerosol-Wolken-Wechselwirkungen in Flüssigwasserwolken über Leipzig untersucht. Die angewandte Messmethode beruht auf der Detektion von Licht, das an Wolkentröpfchen mehrfach in Vorwärtsrichtung gestreut und an Stickstoffmolekülen inelastisch zurückgestreut wurde. Dabei werden zwei Gesichtsfelder unterschiedlicher Größe verwendet. Ein Vorwärtsiterations-Algorithmus nutzt die gewonnenen Informationen zur Ermittlung von Profilen wolkenmikrophysikalischer Eigenschaften. Es können der Extinktionskoeffizient, der effektive Tröpfchenradius, der Flüssigwassergehalt sowie die Tröpfchenanzahlkonzentration bestimmt werden. Weiterhin wird die exakte Erfassung der Wolkenunterkantenhöhe durchdie eingesetzte Messtechnik ermöglicht. Darüber hinaus ist die Bestimmung von Aerosoleigenschaften mit dem eingesetzten Lidargerät möglich. Die Qualität des realisierten Messaufbaus wurde geprüft und eine Fehleranalyse durchgeführt. Unter anderem wurde der aus einer Wolkenmessung bestimmte Flüssigwassergehalt mit einem Mikrowellen-Radiometer bestätigt. Anhand von Fallbeispielen konnte das Potential dieser Messtechnik demonstriert werden. Die Bedeutung von Profilinformationen von Wolkeneigenschaften für die Untersuchung von Aerosol-Wolken-Wechselwirkungen wurde gezeigt. Weiterhin wurde mit Hilfe eines Doppler-Windlidars der Einfluss der Vertikalwindgeschwindigkeit auf Wolkeneigenschaften und damit Aerosol-Wolken-Wechselwirkungen verdeutlicht. Neunundzwanzig Wolkenmessungen wurden für eine statistische Auswertung bezüglich Aerosol-Wolken-Wechselwirkungen genutzt. Dabei konnte erstmalig die Abhängigkeit von Aerosol-Wolken-Wechselwirkungen von der Wolkeneindringtiefe untersucht werden. Es wurde festgestellt, dass diese auf die untersten 70m von Wolken beschränkt sind. Weiterhin wurden deutlich stärkere Aerosol-Wolken-Wechselwirkungen in Wolkengebieten festgestellt, die von Aufwinden dominiert werden. Für der Quantifizierung der Stärke von Aerosol-Wolken-Wechselwirkungen wurden ACIN-Werte genutzt, welche den Zusammenhang zwischen der Tröpfchenanzahlkonzentration und dem Aerosol-Extinktionskoeffizienten beschreiben. Dabei wurde zwischen der Untersuchung der entsprechenden mikrophysikalischen Prozesse und deren Bedeutung für die Wolkenalbedo und damit dem Strahlungsantrieb der Wolken unterschieden. Für die erstgenannte Zielstellung wurde ein ACIN-Wert von 0.80 +/- 0.40 ermittelt, für Letztere 0.13 +/- 0.07.

The ubiquitous abundance of organic compounds in natural and anthorpogenically influenced eco-systems has put these compounds into the focus of atmospheric research. Organic compounds have an impact on air quality, climate, and human health. Moreover, they affect particle growth, secondary organic aerosol (SOA) formation, and the global radiation budget by altering particle properties. To investigate the multiphase chemistry of organic compounds and interactions with the aqueous phase in the troposphere, modelling can provide a useful tool. The oxidation of larger organic molecules to the final product CO2 can involve a huge number of intermediate compounds and tens of thousands of reactions. Therefore, the creation of explicit mechanisms relies on automated mechanism construction. Estimation methods for the prediction of the kinetic data needed to describe the degradation of these intermediates are inevitable due to the infeasibility of an experimental determination of all necessary data. Current aqueous phase descriptions of organic chemistry lag behind the gas phase descriptions in atmospheric chemical mechanisms despite its importance for the multiphase chemistry of organic compounds. In this dissertation, the gas phase mechanism Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) has been advanced by a protocol for the description of the oxidation of organic compounds in the aqueous phase. Therefore, a database with kinetic data of 465 aqueous phase hydroxyl radical and 129 aqueous phase nitrate radical reactions with organic compounds has been compiled and evaluated. The database was used to evaluate currently available estimation methods for the prediction of aqueous phase kinetic data of reactions of organic compounds. Among the investigated methods were correlations of gas and aqueous kinetic data, kinetic data of homologous series of various compound classes, reactivity comparisons of inorganic radical oxidants, Evans-Polanyi-type correlations, and structure-activity relationships (SARs). Evans-Polanyi-type correlations have been improved for the purpose of automated mechanism self-generation of mechanisms with large organic molecules. A protocol has been designed based on SARs for hydroxyl radical reactions and the improved Evans-Polanyi-type correlations for nitrate radical reactions with organic compounds. The protocol was assessed in a series of critical sensitivity studies, where uncertainties of critical parameters were investigated. The advanced multiphase generator GECKO-A was used to generate mechanisms, which were applied in box model studies and validated against two sets of aerosol chamber experiments. Experiments differed by the initial compounds used (hexane and trimethylbenzene) and the experimental conditions (UV-C lights off/on and additional in-situ hydroxyl radical source no/yes). Reasonable to good agreement of the modelled and experimental results was achieved in these studies. Finally, GECKO-A was used to create two new CAPRAM version, where, for the first time, branchingratios for different reaction pathways were introduced and the chemistry of compounds with up to four carbon atoms has been extended. The most detailed mechanism comprises 4174 compounds and 7145 processes. Detailed investigations were performed under real tropospheric conditions in urban and remote continental environments. Model results showed significant improvements, especially in regard to the formation of organic aerosol mass. Detailed investigations of concentration-time profiles and chemical fluxes refined the current knowledge of the multiphase processing of organic compounds in the troposphere, but also pointed at current limitations of the generator protocol, the mechanisms created, and current understanding of aqueous phase processes of organic compounds.:1 Introduction and motivation 2 Theoretical background 2.1 General overview of the tropospheric multiphase chemistry of organic compounds 2.1.1 Gas phase chemistry 2.1.2 Phase transfer 2.1.3 Aqueous phase chemistry 2.2 Tropospheric multiphase chemistry mechanisms 2.2.1 Gas phase mechanisms 2.2.2 Aqueous phase mechanisms 2.2.3 The multiphase mechanism MCMv3.1-CAPRAM 3.0n 2.2.3.1 MCMv3.1 2.2.3.2 CAPRAM 3.0n 2.3 Multiphase chemistry box models 2.3.1 Overview 2.3.2 The model SPACCIM 2.3.2.1 Overview 2.3.2.2 The microphysical scheme 2.3.2.3 The chemical and phase transfer scheme 2.3.2.4 The coupling scheme 2.4 Prediction of aqueous phase kinetic data 2.4.1 Simple correlations 2.4.2 Evans-Polanyi-correlations 2.4.3 Structure-activity relationships 2.5 The generator GECKO-A 3 Evaluation of kinetic data and prediction methods 3.1 Compilation and evaluation of aqueous phase kinetic data 3.2 Extrapolation of gas phase rate constants to the aqueous phase 3.3 Homologous series of compound classes 3.4 Radical reactivity comparisons 3.5 Evans-Polanyi-type correlations 3.5.1 OH rate constant prediction 3.5.2 NO3 rate constant prediction 3.5.3 Development of an advanced Evans-Polanyi-type correlation 3.6 Structure-activity relationships 3.7 Conclusions from the evaluation process 4 Development of the new aqueous phase protocol and its implementation into GECKO-A 4.1 Initialisation and workflow of GECKO-A 4.2 Estimation of phase transfer data 4.3 OH reactions of stable compounds 4.4 NO3 reactions of stable compounds 4.5 Hydration of carbonyl compounds 4.6 Hydrolysis of carbonyl nitrates 4.7 Dissociation of carboxylic acids 4.8 Degradation of radical compounds 4.8.1 RO2 recombinations and cross-reactions 4.8.2 HO2 elimination of ff-hydroxy peroxy radicals 4.8.3 Degradation of acylperoxy radicals 4.8.4 Degradation of fi-carboxyl peroxy radicals 4.8.5 Degradation of alkoxy radicals 4.8.6 Degradation of acyloxy radicals 5 Investigation and refinement of crucial parameters in GECKO-A and CAPRAM mechanism development 5.1 Formation and degradation of polycarbonyl compounds in the protocol 5.2 Influence of the mass accommodation coefficient on the organic multiphase chemistry and composition 5.3 Influence of the cut-off parameter for minor reaction pathways 5.4 Influence of the chosen SAR in the protocol 5.5 Processing of organic mass fraction in the protocol 5.5.1 Parameterisations for radical attack of the overall organic mass fraction 5.5.2 Detailed studies of organic nitrate sinks and sources 5.5.3 Phase transfer of oxygenated organic compounds in the protocol 5.5.4 Decay of alkoxy radicals in the protocol 5.5.5 Revision of the GROMHE thermodynamic database 5.6 Influence of the nitrate radical chemistry 5.7 The final protocol for aqueous phase mechanism self-generation 5.8 CAPRAM mechanism development 5.8.1 CAPRAM 3.0 5.8.2 CAPRAM 3.5 5.8.3 CAPRAM 4.0 6 Model results and discussion 6.1 Comparisons of model results with aerosol chamber experiments 6.1.1 Design of the aerosol chamber experiments 6.1.1.1 Hexane oxidation experiment 6.1.1.2 Trimethylbenzene oxidation experiment 6.1.2 Mechanism generation and model setup 6.1.2.1 Hexane oxidation experiment 6.1.2.2 Trimethylbenzene oxidation experiment 6.1.3 Evaluation of the model versus aerosol chamber results 6.1.3.1 Hexane oxidation experiment 6.1.3.2 Trimethylbenzene oxidation experiment 6.2 Simulations with a ‘real atmosphere’ scenario 6.2.1 Model setup 6.2.2 Meteorological and microphysical parameters 6.2.3 Influence of the extended organic scheme on the particle acidity and SOA formation 6.2.3.1 Particle acidity 6.2.3.2 Particle mass 6.2.4 Influence of the extended organic scheme on inorganic radical oxidants 6.2.4.1 OH chemistry 6.2.4.2 NO3 chemistry 6.2.4.3 Comparison of OH and NO3 chemistry 6.2.4.4 HO2/O2- chemistry 6.2.5 Influence of the extended organic scheme on inorganic non-radical oxidants 6.2.5.1 H2O2 chemistry 6.2.5.2 O3 chemistry 6.2.6 Influence of the extended organic scheme on inorganic particulate matter 6.2.6.1 Sulfate chemistry 6.2.6.2 Nitrate chemistry 6.2.6.3 TMI chemistry 6.2.7 Detailed investigations of selected organic subsystems 6.2.7.1 Monofunctional organic compounds 6.2.7.2 Carbonyl compounds 6.2.7.3 Dicarboxylic acids and functionalised monocarboxylic acids 7 Conclusions References Glossary Acronyms List of symbols List of Figures List of Tables Acknowledgements Curriculum Vitae List of relevant publications Peer-reviewed publications Oral conference contributions Poster conference contributions Appendix A Overview of selected compound classes of tropospheric relevance B Detailed description of the function of SARs C The kinetic database C.1 Reactions of hydroxyl radicals with organic compounds C.2 Reactions of nitrate radicals with organic compounds D Detailed information about the evaluation of prediction methods D.1 Rate data used for the derivation and evaluation of gas-aqueous phase correlations D.2 Explanation of the use of box plots D.3 Additional correlations of homologous series of various compound classes D.4 Additional information of Evans-Polanyi-type correlations D.5 Additional information of structure-activity relationships E Additional information for the development of the protocol of GECKO-A E.1 Investigations on the decay of acylperoxy radicals E.2 Additional information about the sensitivity of mass accomodation coefficients E.3 Additional information about the sensitivity studies concerning the decay of polycarbonyls E.4 Additional information about the sensitivity studies concerning the omission of minor reaction pathways E.5 Additional information about the sensitivity studies concerning the processing of the organic mass fraction E.6 Additional information about the influence of the nitrate radical chemistry F Additional information about the mechanism generation and model initialisation F.1 List of primary compounds used for the generation of CAPRAM 3.5 F.2 List of primary compounds used for the generation of CAPRAM 4.0 F.3 Model initialization of the ‘real atmosphere’ scenarios G The CAPRAM oxidation scheme G.1 Photolysis processes G.2 Inorganic chemistry G.2.1 Phase transfer processes G.2.2 Chemical conversions G.3 Organic chemistry G.3.1 Phase transfer processes G.3.2 Chemical conversions H Detailed information about the model validation with chamber experiments H.1 Additional information about the initialisation of the hexane oxidation experiment H.2 Additional model results from the hexane oxidation experiment H.3 Additional information about the sensitivity runs used in the trimethylbenzene oxidation experiment H.4 Additional results from the TMB oxidation experiment I Additional results from the ‘real atmosphere’ scenario I.1 Particle acidity and SOA formation I.2 Radical oxidants I.3 Organic compounds References of the Appendix / Das zahlreiche Vorkommen organischer Verbindungen in natürlichen und anthropogen beeinflussten Ökosystemen hat diese Verbindungen in den Fokus der Atmosphärenforschung gerückt. Organische Verbindungen beeinträchtigen die Luftqualität, die menschliche Gesundheit und das Klima. Weiterhin werden Partikelwachstum und -eigenschaften, sekundäre organische Partikelbildung und dadurch der globale Strahlungshaushalt durch sie beeinflusst. Um die troposphärische Multiphasenchemie organischer Verbindungen und Wechselwirkungen mit der Flüssigphase zu untersuchen, sind Modellstudien hilfreich. Die Oxidation großer organischer Moleküle führt zu einer Vielzahl an Zwischenprodukten. Der Abbau erfolgt in unzähligen Reaktionen bis hin zum Endprodukt CO2. Bei der Entwicklung expliziter Mechanismen muss deshalb für diese Verbindungen auf computergestützte, automatisierte Methoden zurückgegriffen werden. Abschätzungsmethoden für die Vorhersage kinetischer Daten zur Beschreibung des Abbaus der Zwischenprodukte sind unabdingbar, da eine experimentelle Bestimmung aller benötigten Daten nicht realisierbar ist. Die derzeitige Beschreibung der Flüssigphasenchemie unterliegt deutlich den Beschreibungen der Gasphase in atmosphärischen Chemiemechanismen trotz deren Relevanz für die Multiphasenchemie. In dieser Arbeit wurde der Gasphasenmechanismusgenerator GECKO-A (“Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere”) um ein Protokoll zur Oxidation organischer Verbindungen in der Flüssigphase erweitert. Dazu wurde eine Datenbank mit kinetischen Daten von 465 Hydroxylradikal- und 129 Nitratradikalreaktionen mit organischen Verbindungen angelegt und evaluiert. Mit Hilfe der Datenbank wurden derzeitige Abschätzungsmethoden für die Vorhersage kinetischer Daten von Flüssigphasenreaktionen organischer Verbindungen evaluiert. Die untersuchten Methoden beinhalteten Korrelationen kinetischer Daten aus Gas- und Flüssigphase, homologer Reihen verschiedener Stoffklassen, Reaktivitätsvergleiche, Evans-Polanyi-Korrelationen und Struktur-Reaktivitätsbeziehungen. Für die Mechanismusgenerierung großer organischer Moleküle wurden die Evans-Polanyi-Korrelationen in dieser Arbeit weiterentwickelt. Es wurde ein Protokol für die Mechanismusgenerierung entwickelt, das auf Struktur-Reaktivitätsbeziehungen bei Reaktionen von organischen Verbindungen mit OH-Radikalen und auf den erweiterten Evans-Polanyi-Korrelationen bei NO3-Radikalreaktionen beruht. Das Protokoll wurde umfangreich in einer Reihe von Sensitivitätsstudien getestet, um Unsicherheiten kritischer Parameter abzuschätzen. Der erweiterte Multiphasengenerator GECKO-A wurde dazu verwendet, neue Mechanismen zu generieren, die in Boxmodellstudien gegen Aerosolkammerexperimente evaluiert wurden. Die Experimentreihen unterschieden sich sowohl in der betrachteten Ausgangssubstanz (Hexan und Trimethylbenzen) und dem Experimentaufbau (ohne oder mit UV-C-Photolyse und ohne oder mit zusätzlicher partikulärer Hydroxylradikalquelle). Bei den Experimenten konnte eine zufriedenstellende bis gute Übereinstimmung der experimentellen und Modellergebnisse erreicht werden. Weiterhin wurde GECKO-A verwendet, um zwei neue CAPRAM-Versionen mit bis zu 4174 Verbindungen und 7145 Prozessen zu generieren. Erstmals wurden Verzweigungsverhältnisse in CAPRAM eingeführt. Außerdem wurde die Chemie organischer Verbindungen mit bis zu vier Kohlenstoffatomen erweitert. Umfangreiche Untersuchungen unter realistischen troposphärischen Bedingungen in urbanen und ländlichen Gebieten haben deutliche Verbesserungen der erweiterten Mechanismen besonders in Bezug auf Massenzuwachs des organischen Aerosolanteils gezeigt. Das Verständnis der organischen Multiphasenchemie konnte durch detaillierte Untersuchungen zu den Konzentrations-Zeit-Profilen und chemischen Flüssen vertieft werden, aber auch gegenwärtige Limitierungen des Generators, der erzeugten Mechanismen und unseres Verständnisses für Flüssigphasenprozesse organischer Verbindungen aufgezeigt werden.:1 Introduction and motivation 2 Theoretical background 2.1 General overview of the tropospheric multiphase chemistry of organic compounds 2.1.1 Gas phase chemistry 2.1.2 Phase transfer 2.1.3 Aqueous phase chemistry 2.2 Tropospheric multiphase chemistry mechanisms 2.2.1 Gas phase mechanisms 2.2.2 Aqueous phase mechanisms 2.2.3 The multiphase mechanism MCMv3.1-CAPRAM 3.0n 2.2.3.1 MCMv3.1 2.2.3.2 CAPRAM 3.0n 2.3 Multiphase chemistry box models 2.3.1 Overview 2.3.2 The model SPACCIM 2.3.2.1 Overview 2.3.2.2 The microphysical scheme 2.3.2.3 The chemical and phase transfer scheme 2.3.2.4 The coupling scheme 2.4 Prediction of aqueous phase kinetic data 2.4.1 Simple correlations 2.4.2 Evans-Polanyi-correlations 2.4.3 Structure-activity relationships 2.5 The generator GECKO-A 3 Evaluation of kinetic data and prediction methods 3.1 Compilation and evaluation of aqueous phase kinetic data 3.2 Extrapolation of gas phase rate constants to the aqueous phase 3.3 Homologous series of compound classes 3.4 Radical reactivity comparisons 3.5 Evans-Polanyi-type correlations 3.5.1 OH rate constant prediction 3.5.2 NO3 rate constant prediction 3.5.3 Development of an advanced Evans-Polanyi-type correlation 3.6 Structure-activity relationships 3.7 Conclusions from the evaluation process 4 Development of the new aqueous phase protocol and its implementation into GECKO-A 4.1 Initialisation and workflow of GECKO-A 4.2 Estimation of phase transfer data 4.3 OH reactions of stable compounds 4.4 NO3 reactions of stable compounds 4.5 Hydration of carbonyl compounds 4.6 Hydrolysis of carbonyl nitrates 4.7 Dissociation of carboxylic acids 4.8 Degradation of radical compounds 4.8.1 RO2 recombinations and cross-reactions 4.8.2 HO2 elimination of ff-hydroxy peroxy radicals 4.8.3 Degradation of acylperoxy radicals 4.8.4 Degradation of fi-carboxyl peroxy radicals 4.8.5 Degradation of alkoxy radicals 4.8.6 Degradation of acyloxy radicals 5 Investigation and refinement of crucial parameters in GECKO-A and CAPRAM mechanism development 5.1 Formation and degradation of polycarbonyl compounds in the protocol 5.2 Influence of the mass accommodation coefficient on the organic multiphase chemistry and composition 5.3 Influence of the cut-off parameter for minor reaction pathways 5.4 Influence of the chosen SAR in the protocol 5.5 Processing of organic mass fraction in the protocol 5.5.1 Parameterisations for radical attack of the overall organic mass fraction 5.5.2 Detailed studies of organic nitrate sinks and sources 5.5.3 Phase transfer of oxygenated organic compounds in the protocol 5.5.4 Decay of alkoxy radicals in the protocol 5.5.5 Revision of the GROMHE thermodynamic database 5.6 Influence of the nitrate radical chemistry 5.7 The final protocol for aqueous phase mechanism self-generation 5.8 CAPRAM mechanism development 5.8.1 CAPRAM 3.0 5.8.2 CAPRAM 3.5 5.8.3 CAPRAM 4.0 6 Model results and discussion 6.1 Comparisons of model results with aerosol chamber experiments 6.1.1 Design of the aerosol chamber experiments 6.1.1.1 Hexane oxidation experiment 6.1.1.2 Trimethylbenzene oxidation experiment 6.1.2 Mechanism generation and model setup 6.1.2.1 Hexane oxidation experiment 6.1.2.2 Trimethylbenzene oxidation experiment 6.1.3 Evaluation of the model versus aerosol chamber results 6.1.3.1 Hexane oxidation experiment 6.1.3.2 Trimethylbenzene oxidation experiment 6.2 Simulations with a ‘real atmosphere’ scenario 6.2.1 Model setup 6.2.2 Meteorological and microphysical parameters 6.2.3 Influence of the extended organic scheme on the particle acidity and SOA formation 6.2.3.1 Particle acidity 6.2.3.2 Particle mass 6.2.4 Influence of the extended organic scheme on inorganic radical oxidants 6.2.4.1 OH chemistry 6.2.4.2 NO3 chemistry 6.2.4.3 Comparison of OH and NO3 chemistry 6.2.4.4 HO2/O2- chemistry 6.2.5 Influence of the extended organic scheme on inorganic non-radical oxidants 6.2.5.1 H2O2 chemistry 6.2.5.2 O3 chemistry 6.2.6 Influence of the extended organic scheme on inorganic particulate matter 6.2.6.1 Sulfate chemistry 6.2.6.2 Nitrate chemistry 6.2.6.3 TMI chemistry 6.2.7 Detailed investigations of selected organic subsystems 6.2.7.1 Monofunctional organic compounds 6.2.7.2 Carbonyl compounds 6.2.7.3 Dicarboxylic acids and functionalised monocarboxylic acids 7 Conclusions References Glossary Acronyms List of symbols List of Figures List of Tables Acknowledgements Curriculum Vitae List of relevant publications Peer-reviewed publications Oral conference contributions Poster conference contributions Appendix A Overview of selected compound classes of tropospheric relevance B Detailed description of the function of SARs C The kinetic database C.1 Reactions of hydroxyl radicals with organic compounds C.2 Reactions of nitrate radicals with organic compounds D Detailed information about the evaluation of prediction methods D.1 Rate data used for the derivation and evaluation of gas-aqueous phase correlations D.2 Explanation of the use of box plots D.3 Additional correlations of homologous series of various compound classes D.4 Additional information of Evans-Polanyi-type correlations D.5 Additional information of structure-activity relationships E Additional information for the development of the protocol of GECKO-A E.1 Investigations on the decay of acylperoxy radicals E.2 Additional information about the sensitivity of mass accomodation coefficients E.3 Additional information about the sensitivity studies concerning the decay of polycarbonyls E.4 Additional information about the sensitivity studies concerning the omission of minor reaction pathways E.5 Additional information about the sensitivity studies concerning the processing of the organic mass fraction E.6 Additional information about the influence of the nitrate radical chemistry F Additional information about the mechanism generation and model initialisation F.1 List of primary compounds used for the generation of CAPRAM 3.5 F.2 List of primary compounds used for the generation of CAPRAM 4.0 F.3 Model initialization of the ‘real atmosphere’ scenarios G The CAPRAM oxidation scheme G.1 Photolysis processes G.2 Inorganic chemistry G.2.1 Phase transfer processes G.2.2 Chemical conversions G.3 Organic chemistry G.3.1 Phase transfer processes G.3.2 Chemical conversions H Detailed information about the model validation with chamber experiments H.1 Additional information about the initialisation of the hexane oxidation experiment H.2 Additional model results from the hexane oxidation experiment H.3 Additional information about the sensitivity runs used in the trimethylbenzene oxidation experiment H.4 Additional results from the TMB oxidation experiment I Additional results from the ‘real atmosphere’ scenario I.1 Particle acidity and SOA formation I.2 Radical oxidants I.3 Organic compounds References of the Appendix

In der eingereichten Dissertation wird eine Reihe von niederdimensionalen und frustrierten magnetischen Systemen mit Hilfe der Elektronenspinresonanz (ESR) untersucht, um deren magnetische Eigenschaften und Wechselwirkungen zu charakterisieren. Sowohl niederdimensionale als auch frustrierte Systeme können exotische magnetische Phänomene zeigen, da es in beiden Fällen trotz starker magnetischer Korrelationen zu einer Unterdrückung von konventioneller langreichweitiger magnetischer Ordnung kommen kann. Auf der anderen Seite sind zweidimensionale Systeme wie Graphen und die damit verwandten topologischen Isolatoren interessant für Anwendungen in der Spintronik oder in Quantencomputern. Über das Einbringen von magnetischer Ordnung soll dabei die Kontrolle über den Spin von Elektronen erlangt werden. Es werden quasieindimensionale Spinketten in Cu(py)2Br2 untersucht, die ein gutes Modellsysteme für den Vergleich mit exakten theoretischen Berechnungen darstellen. Durch eingehende ESR-Messungen ist es gelungen, ein Modell für die Ausrichtung der Anisotropieachse zu entwickeln, die senkrecht zur Kettenachse steht. Zusätzlich zum g-Tensor konnten durch Magnetisierungsmessungen das Austauschintegral und dessen Anisotropie bestimmt werden. Die Austauschwechselwirkung kann über die Substitution von Br- mit Cl-Ionen in Cu(py)2(Cl1-xBrx)2 gezielt variiert werden. Des Weiteren wird eine kombinierte Studie aus STM- und ESR-Untersuchungen an monolagigem Graphen mit induzierten Fehlstellen vorgestellt. Es wurden Defekte durch den Beschuss mit Ar-Ionen in Graphen kontrolliert hergestellt, deren lokale elektronische Eigenschaften sich mit STM- und STS-Messungen charakte-risieren lassen. Mit ESR-Messungen konnte gezeigt werden, dass die an den einzelnen Fehlstellen lokalisierten magnetischen Momente eine dominant antiferromagnetische Austauschwechselwirkung besitzen. Die Charakterisierung der magnetischen Wechselwirkungen zwischen lokalisierten Momenten stand auch für den mit Mn dotierten topologischen Isolator Bi2Te3 im Vordergrund, welcher einen ferromagnetischen Phasenübergang bei tiefen Temperaturen zeigt. Anhand des mit ESR beobachteten Korringa-Verhaltens wurde bewiesen, dass die lokalisierten Mn-Spins an leitende Bänder gekoppelt sind und die ferromagnetische Ordnung folglich per RKKY-Wechselwirkung vermittelt wird. Es wurden kurzreichweitige magnetische Korrelationen in einem ausgedehnten Temperaturbereich oberhalb der Ordnungstemperatur beobachtet, die Hinweise auf einen zweidimensionalen Charakter zeigen. Ausgedehnte Temperaturbereiche mit kurzreichweitigen Korrelationen werden ebenfalls in den untersuchten magnetisch frustrierten Materialien beobachtet. In einer kombinierten Studie aus HF-ESR, NMR und µSR wird die Spindynamik in CoAl2O4 charakterisiert, in dem moderate Unordnung zu einem Verschwimmen der Phasengrenze zwischen Neél-Ordnung und einer Spinflüssigkeit mit spiralförmigen Korrelationen führt. Außerdem werden zwei Vertreter aus der Klasse der Swedenborgite behandelt, in denen die Spinstruktur in YBaCo4O7 durch Substitution modifiziert wird. Ziel ist die Entkopplung der enthaltenen Kagome-Schichten, welche ein zweidimensionales frustriertes System darstellen. In den vorgestellten HF-ESR- und NMR-Messungen beobachtet man ein Spinglasverhalten für YBaCo3AlO7, das aus der Unordnung bei der Besetzung der Gitterplätze resultiert. In YBaCo3FeO7 ist die Unordnung geringer und mit ESR-Untersuchungen konnte gezeigt werden, dass es zu einer effektiven Entkopplung der Fe-Spins zwischen den Kagome-Schichten kommt.

The general aim of my dissertation was to investigate the role of plant interactions in driving population dynamics. Both theoretical and empirical approaches were employed. All my studies were conducted on the basis of metabolic scaling theory (MST), because the complex, spatially and temporally varying structures and dynamics of ecological systems are considered to be largely consequences of biological metabolism. However, MST did not consider the important role of plant interactions and was found to be invalid in some environmental conditions. Integrating the effects of plant interactions and environmental conditions into MST may be essential for reconciling MST with observed variations in nature. Such integration will improve the development of theory, and will help us to understand the relationship between individual level process and system level dynamics. As a first step, I derived a general ontogenetic growth model for plants which is based on energy conservation and physiological processes of individual plant. Taking the mechanistic growth model as basis, I developed three individual-based models (IBMs) to investigate different topics related to plant population dynamics: 1. I investigated the role of different modes of competition in altering the prediction of MST on plant self-thinning trajectories. A spatially-explicit individual-based zone-of-influence (ZOI) model was developed to investigate the hypothesis that MST may be compatible with the observed variation in plant self-thinning trajectories if different modes of competition and different resource availabilities are considered. The simulation results supported my hypothesis that (i) symmetric competition (e.g. belowground competition) will lead to significantly shallower self-thinning trajectories than asymmetric competition as predicted by MST; and (ii) individual-level metabolic processes can predict population-level patterns when surviving plants are barely affected by local competition, which is more likely to be in the case of asymmetric competition. 2. Recent studies implied that not only plant interactions but also the plastic biomass allocation to roots or shoots of plants may affect mass-density relationship. To investigate the relative roles of competition and plastic biomass allocation in altering the mass-density relationship of plant population, a two-layer ZOI model was used which considers allometric biomass allocation to shoots or roots and represents both above- and belowground competition simultaneously via independent ZOIs. In addition, I also performed greenhouse experiment to evaluate the model predictions. Both theoretical model and experiment demonstrated that: plants are able to adjust their biomass allocation in response to environmental factors, and such adaptive behaviours of individual plants, however, can alter the relative importance of above- or belowground competition, thereby affecting plant mass-density relationships at the population level. Invalid predictions of MST are likely to occur where competition occurs belowground (symmetric) rather than aboveground (asymmetric). 3. I introduced the new concept of modes of facilitation, i.e. symmetric versus asymmetric facilitation, and developed an individual-based model to explore how the interplay between different modes of competition and facilitation changes spatial pattern formation in plant populations. The study shows that facilitation by itself can play an important role in promoting plant aggregation independent of other ecological factors (e.g. seed dispersal, recruitment, and environmental heterogeneity). In the last part of my study, I went from population level to community level and explored the possibility of combining MST and unified neutral theory of biodiversity (UNT). The analysis of extensive data confirms that most plant populations examined are nearly neutral in the sense of demographic trade-offs, which can mostly be explained by a simple allometric scaling rule based on MST. This demographic equivalence regarding birth-death trade-offs between different species and functional groups is consistent with the assumptions of neutral theory but allows functional differences between species. My initial study reconciles the debate about whether niche or neutral mechanisms structure natural communities: the real question should be when and why one of these factors dominates. A synthesis of existing theories will strengthen future ecology in theory and application. All the studies presented in my dissertation showed that the approaches of individual-based and pattern-oriented modelling are promising to achieve the synthesis.

Es wird heute weltweit versucht, Konzepte für vielfältige taktile kartographische Medien zu entwickeln, die vorrangig der allgemeinen Orientierung und Mobilität, aber auch verstärkt dem Wissenserwerb, z.B. im Geographieunterricht an Schulen für Blinde und Sehbehinderte, dienen sollen. Diese Konzepte müssen von denen der "visuellen Kartographie"1 zwangsläufig mehr oder weniger abweichen und auf weitgehend anderen Methoden, Regeln und Techniken beruhen. Wesentliche und durch die Praxis verifizierte Erkenntnisse der visuellen Kartographie sind der taktilen Kartographie zugänglich zu machen bzw. in/an diese zu adaptieren. Trotzdem dürfen grundlegende Theorien und Erfahrungen der Kartengestaltung und Kartennutzung für Sehende nicht völlig negiert werden.

The docotoral thesis titled 'Modeling the effects of Transient Stream Flow on Solute Dynamics in Stream Banks and Intra-meander Zones' investigates flow and solute dynamcis across surface water-groundwater interface under dynamic flow conditons through numerical simulations. The abstract of the thesis is as follows: Waters from various sources meet at the interface between streams and groundwater. Due to their different origins, these waters often have contrasting chemical signatures and therefore mixing of water at the interface may lead to significant changes in both surface and subsurface water quality. The riparian zone adjacent to the stream serves as transition region between groundwater and stream water, where complex water and solute mixing and transport processes occur. Predicting the direction and the magnitude of solute exchanges and the extent of transformations within the riparian zone is challenging due to the varying hydrologic and chemical conditions as well as heterogeneous morphological features which result in complex, three-dimensional flow patterns. The direction of water flow and solute transport in the riparian zone typically varies over time as a result of fluctuating stream water and groundwater levels. Particularly, increasing groundwater levels can mobilize solutes from the unsaturated zone which can be subsequently transported into the stream. Such complex, spatially and temporally varying processes are hard to capture with field observations alone and therefore modeling approaches are required to predict the system behavior as well as to understand the role of individual factors. In this thesis, we investigate the inter-connectivity of streamthe s and adjacent riparia zones in the context of water and solute exchanges both laterally for bank storage and longitudinally for hyporheic flow through meander bends. Using numerical modeling, the transient effect of stream flow events on solute transport and transformation within the initially unsaturated part of stream banks and meander bends have been simulated using a systematic set of hydrological, chemical and morphological scenarios. A two dimensional variably saturated media groundwater modeling set up was used to explore solute dynamics during bank flows. We simulated exchanges between stream and adjacent riparian zone driven by stream stage fluctuations during stream discharge events. To elucidate the effect of magnitude and duration of discharge events, we developed a number of single discharge event scenarios with systematically varying peak heights and event duration. The dominant solute layer was represented by applying high solute concentration in upper unsaturated riparian zone profile. Simulated results show that bank flows generated by high stream flow events can trigger solute mobilization in near stream riparian soils and subsequently export significant amounts of solutes into the stream. The timing and amount of solute export is linked to the shape of the discharge event. Higher peaks and increased duration significantly enhance solute export, however, peak height is found to be the dominant control for overall lateral mass export. The mobilized solutes are transported towards the stream in two stages (1) by return flow of stream water that was stored in the riparian zone during the event and (2) by vertical movement to the groundwater under gravity drainage from the unsaturated parts of the riparian zone, which lasts for significantly longer time (> 400 days) resulting in a theoretically long tailing of bank outflows and solute mass outfluxes. Our bank flow simulations demonstrate that strong stream discharge events are likely to mobilize and export significant quantity of solutes from near stream riparian zones into the stream. Furthermore, the impact of short-term stream discharge variations on solute exchange may sustain for long times after the flow event. Meanders are prominent morphological features of stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange flow through the intrameander region, leading to solute transport and reactions within intra-meander region. We examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady-state and transient flow conditions. In order to explore the impact of meander morphology on intrameander flow, a number of theoretical meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander were developed. Three dimensional steady-state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region for all meander scenarios. The meandering stream was implemented in the model by adjusting the top layers of the modeling domain to the streambed elevation. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. Similar to the bank storage case, a high concentration of solute (carbon source) representing the dominant solute layer in the riparian profile was added in the unsaturated zone to evaluate the effect of stream flow event on mobilization and transport from the unsaturated part of intrameander region. Additionally, potential chemical reactions of aerobic respiration by the entry of oxygen rich surface water into subsurface as well denitrification due to stream and groundwater borne nitrates were also simulated. The results indicate that intra-meander mean residence times ranging from 18 to 61 days are influenced by meander geometry, as well as the size of the intra-meander area. We found that, intra-meander hydraulic gradient is the major control of RTs. In general, larger intra-meander areas lead to longer flow paths and higher mean intra-meander residence times (MRTs), whereas increased meander sinuosity results in shorter MRTs. The vertical extent of hyporheic flow paths generally decreases with increasing sinuosity. Transient modeling of hyporheic flow through meanders reveals that large stream flow events mobilize solutes from the unsaturated portion of intra-meander region leading to consequent transport into the stream via hyporheic flow. Advective solute transport dominates during the flow event; however significant amount of carbon is also consumed by aerobic respiration and denitrification. These reactions continue after the flow events depending upon the availability of carbon source. The thesis demonstrates that bank flows and intra-meander hyporheic exchange flows trigger solute mobilization from the dominant solute source layers in the RZ. Stream flow events driven water table fluctuations in the stream bank and in the intra-meander region transport substantial amount of solutes from the unsaturated RZ into the stream and therefore have significant potential to alter stream water quality.:Declaration Abstract Zusammenfassung 1 General Introduction 1.1 Background and Motivation 1.2 Hydrology and Riparian zones 1.2.1 Transport processes driven by fluctuation in riparian water table depth 1.2.1.1 Upland control 1.2.1.2 Stream control 1.2.2 Biochemical Transformations within the Riparian Zone 1.3 Types and scales of stream-riparian exchange 1.3.1 Hyporheic Exchange 1.3.1.1 Small Scale Vertical HEF 1.3.1.2 Large Scale lateral HEF 1.3.2 Bank Storage 1.4 Methods for estimation of GW-SW exchanges 1.4.1 Field Methods 1.4.1.1 Direct measurement of water flux 1.4.1.2 Tracer based Methods 1.4.2 Modeling Methods 1.4.2.1 Transient storage models 1.4.2.2 Physically based models 1.5 Research gaps and need 1.6 Objectives of the research 1.7 Thesis Outline 2 Flow and Transport Dynamics during Bank Flows 2.1 Introduction 2.2 Methods 2.2.1 Concept and modeling setup 2.2.2 Numerical Model 2.2.3 Stream discharge events 2.2.4 Model results evaluation 2.3 Results and discussion 2.3.1 Response of water and solute exchange to stream discharge events 2.3.1.1 Water exchange time scales 2.3.1.2 Stream water solute concentration 2.3.2 Solute mobilization within the riparian zone 2.3.3 Influence of peak height and event duration on solute mass export towards the stream 2.3.4 Effects of event hydrograph shape on stream water solute concentration 2.3.5 Model limitations and future studies 2.4 Summary and Conclusions Appendix 2 3 Flow and Transport Dynamics within Intra-Meander Zone 3.1 Introduction 3.2 Methods 3.2.1 Meander Shape Scenarios 3.2.2 Surface Water Simulations 3.2.3 3D Groundwater Flow Simulations with Modeling code MIN3P 3.2.3.1 Steady Flow Simulations 3.2.3.2 Stream flow event and Solute Mobilization Set-up 3.2.4 Reactive Transport 3.3 Results and Discussion 3.3.1 Groundwater heads and flow paths in the saturated intrameander zone 3.3.1.1 Groundwater heads 3.3.1.2 Flow paths and isochrones 3.3.1.3 Vertical extent of flow paths 3.3.2 Intra-Meander Residence Time Distribution 3.3.3 Factors affecting intra-meander flow and residence times 3.3.3.1 intra-meander hydraulic gradient 3.3.3.2 Maximum penetration depth 3.3.3.3 Meander sinuosity 3.3.3.4 intra-meander area (A) 3.3.4 Influence of Discharge Event on intra-meander Flow and Solute Transport 3.3.4.1 Spatial distribution of groundwater head and solute concentration 3.3.4.2 Time scales of intra-meander groundwater heads and solute transport 3.3.4.3 Solute export during stream discharge event 3.3.5 Intra-meander reactive transport during stream discharge event 3.3.5.1 Impact of stream discharge on aerobic respiration and denitrification 3.3.5.2 DOC mass removal during stream discharge event 3.4 Summary and Conclusions Appendix 3 4 General Summary and Conclusions 4.1 Summary 4.2 Conclusions 4.2.1 Flow and Transport Dynamics in Near Stream Riparian Zone (Bank Flows) 4.2.2 Flow and Transport Dynamics within Intra-Meander Zone 4.3 Model Limitations and Future Studies Bibliography Acknowledgement

ICA512/PTPRN is a receptor tyrosine-like phosphatase implicated in the biogenesis and turnover of the insulin secretory granules (SGs) in pancreatic islet beta cells. Previously we found biophysical evidence that its luminal RESP18 homology domain (RESP18HD) forms a biomolecular condensate and interacts with insulin in vitro at close-to-neutral pH, that is, in conditions resembling those present in the early secretory pathway. Here we provide further evidence for the relevance of these findings by showing that at pH 6.8 RESP18HD interacts also with proinsulin—the physiological insulin precursor found in the early secretory pathway and the major luminal cargo of β-cell nascent SGs. Our light scattering analyses indicate that RESP18HD and proinsulin, but also insulin, populate nanocondensates ranging in size from 15 to 300 nm and 10e2 to 10e6 molecules. Co-condensation of RESP18HD with proinsulin/insulin transforms the initial nanocondensates into microcondensates (size >1 μm). The intrinsic tendency of proinsulin to self-condensate implies that, in the ER, a chaperoning mechanism must arrest its spontaneous intermolecular condensation to allow for proper intramolecular folding. These data further suggest that proinsulin is an early driver of insulin SG biogenesis, in a process in which its co-condensation with RESP18HD participates in their phase separation from other secretory proteins in transit through the same compartments but destined to other routes. Through the cytosolic tail of ICA512, proinsulin co-condensation with RESP18HD may further orchestrate the recruitment of cytosolic factors involved in membrane budding and fission of transport vesicles and nascent SGs.

Das Verständnis über die Ausbildung der Grenzfläche eines hybriden Bauteils aus thermoplastischem Kunststoff und Metall sowie die maßgeblichen Faktoren zum Erreichen einer hohen Verbundhaftung und Mediendichtheit in der Grenzfläche stellen nach wie vor eine große Herausforderung dar. Am Beispiel einer spritzgegossenen Kunststoff-Metall-Verbundprobe werden diese Zusammenhänge untersucht und bewertet. Es wird eine Methode zur Herstellung stoffschlüssig gefügter Verbunde mit hoher Mediendichtheit auf Basis einer hohen Kontakttemperatur beim Fügen entwickelt, indem Verbundspritzgießen und nachträgliches thermisches Fügen durch Induktionsheizen kombiniert werden. Eine stoffschlüssige Verbindung mit hoher Mediendichtheit zwischen thermoplastischem Kunststoff und Metall erfordert eine Haftung in der Grenzfläche der Verbundpartner auf Basis intermolekularer Wechselwirkungen. Die Quantifizierung der Mediendichtheit in der Grenzfläche erfolgt über eine eigens entwickelte Messmethode. Die entwickelte Vorgehensweise ermöglichet die Differenzierung zwischen intermolekularen Wechselwirkungen und mechanischen Verklammerungen als Ursache für eine Haftungsausbildung und deren Einfluss auf die Grenzflächeneigenschaften. Die gewonnenen Erkenntnisse tragen zum Verständnis der Grenzflächenausbildung, insbesondere zum Einfluss der Oberflächenbeschaffenheit des metallischen Verbundpartners sowie der Fügeprozessbedingungen zur Fertigung von Kunststoff-Metall-Verbunden mit hoher Mediendichtheit, bei.:1 Einleitung und Motivation 2 Stand der Technik und Forschung 3 Zielsetzung und Lösungsansatz 4 Experimentelles 5 Analytik 6 Ergebnisse 7 Diskussion der Ergebnisse 8 Zusammenfassung und Ausblick / Understanding the formation of the interface of a hybrid component made of thermoplastic and metal as well as the decisive factors for achieving high adhe-sion and media tightness in the interface still represent a major challenge. These relationships are investigated and elucidated using the example of an injection-molded plastic-metal part. A method for the production of firmly bonded hybrid parts with high media tightness based on a high contact temperature during joining of the hybrid part is developed by combining injection molding and subsequent thermal joining by induction heating. A firm bond with high media tightness between a thermoplastic and a metal requires an adhesion in the inter-face of the joint materials based on molecular interactions. The quantification of the media tightness in the interface is done by using a specially developed measurement method. The investigations enable the differentiation between molecular interactions and mechanical interlocking as the cause of adhesion formation and their influence on the properties of the interface. The gained knowledge contributes to the understanding of interface formation and its prop-erties, in particular the influence of the surface properties of the metallic bond partner and the joining process conditions for the production of plastic-metal parts with high media tightness.:1 Einleitung und Motivation 2 Stand der Technik und Forschung 3 Zielsetzung und Lösungsansatz 4 Experimentelles 5 Analytik 6 Ergebnisse 7 Diskussion der Ergebnisse 8 Zusammenfassung und Ausblick

Aufkonvertierungs-Nanokristalle (UCNPs), wie NaYF4 Kristalle, welche mit Yb3+ and Er3+ Ionen dotiert sind, emittieren höher energetisches Licht im ultravioletten/sichtbaren und nahinfraroten Bereich, nachdem sie mit weniger energiereichem nahinfraroten Licht angeregt wurden. Damit besitzen sie einzigartige optische Eigenschaften, wie verschiedenfarbige Emissionsbanden, verringerte Hintergrundfluoreszenz, größere Eindringtiefen in organisches Probenmaterial und eine hohe Lichtstabilität. Diese Eigenschaften sind besonders in der optischen Bioanalyse, in medizinischen und technischen Anwendungen von Vorteil. In dieser Arbeit werden die photophysikalischen und spektralen Eigenschaften von UCNPs im Ensemble und an Einzelpartikeln untersucht. Ein dafür entwickeltes konfokales Mikroskop ermöglicht Einzelpartikelmessungen bis in den Sättigungsbereich der UCNPs bei hohen Laser Anregungsleistungsdichten (P). Die erste Studie dieser Arbeit umfasst Ensemble- und Einzelpartikelmessungen an Kern und Kern-Schale 𝛽-NaYF4 Kristallen, welche mit 20% Yb3+ und 1% bis 3% Er3+ Ionen dotiert sind, wobei die optischen Eigenschaften P-abhängig über sechs Größenordnungen untersucht wurden. Die zweite Studie diskutiert die Einflüsse bei starker Änderung der Yb3+/Er3+ Ionen Dotierung anhand von drei verschiedenen Probensystemen. Diese unterscheiden sich sowohl in der Partikelgröße als auch in der Synthesevorschrift. Bei der dritten Studie wurde die direkte Anregung von Yb3+ mit der von Nd3+ Ionen an Nd/Yb/Er dotierten NaYF4 Partikeln bezüglich des aufkonvertierten Lumineszenz Verhaltens in Wasser verglichen. In weiteren Messungen wurde sowohl der Lumineszenz Resonanz Energie Transfer (LRET) ausgehend von einem UCNP zu dem Farbstoff Sulforhodamine B, als auch plasmonische Wechselwirkungen von Au-Schale UCNPs bei Einzelpartikelmessungen untersucht. / Upconversion nanoparticles (UCNPs), such as, NaYF4 crystals co-doped with Yb3+ and Er3+ ions, emit higher energetic light in the UV/vis and NIR range under lower energetic NIR excitation. This generates unique optical properties, for example, multi-colour band emissions, reduced background fluorescence, deeper tissue penetration depths and high photostability rendering UCNPs attractive options for bioimaging, medicinal and engineering applications. In this thesis the influence of multi-factor parameters on the photo-physical and spectroscopic properties of UCNPs are investigated under ensemble and single particle (SP) condition. For this purpose, a confocal laser scanning microscope was constructed to enable the characterisation of individual UCNPs up to their saturation conditions at high laser power densities (P). At first, ensemble and SP studies of core- and core-shell 𝛽-NaYF4 crystals co-doped with 20% Yb3+ and 1% to 3% Er3+ are performed over a P-range of six orders of magnitude. The second part of this thesis discusses influences in a wide variation in Yb3+/Er3+ ion doping concentration. Thereby, three different sample sets of varying size have been studied, using different synthesis approaches. A comparison of the Nd- and Yb-excitation of Nd/Yb/Er triple-doped NaYF4 UCNPs regarding their upconversion luminescence performance in water is provided in the third section of the thesis. In further studies, the process of luminescence resonance energy transfer (LRET) from an UCNP to the sulforhodamine B dye and the plasmonic interaction of an Au-shelled UCNP have been examined at the SP level.