Photophysics and Photochemistry of Iron Carbene Complexes

Nature captures sunlight via light-absorbing molecules.Similarly, photosensitisers are used in applications of solar cells and artificial photosynthesis to absorb sunlight, and transfer the excited electron.Successful photosensitisers have in the past been based on a Ru polipyridyl scaffold, despite Ru being one of the scarcest elements in Earth's crust.This thesis work aims to replace Ru polipyridyl complexes by Fe carbene complexes, that by clever ligand design have approached suitable photosensitiser properties.One crucial property that is not yet competitive for Fe carbene photosensitisers is how long they stay in the excited state, i.e. their lifetime. This is controlled by the deactivation pathways of the molecule, dictated by the excited state landscape. Several Fe carbene photosensitisers were in this thesis investigated by spectroscopic and computational methods, to understand their deactivation pathways. For the Fe(II) carbene complexes investigated, small changes in the ligand structure influenced both what excited state (charge-transfer or metal-centred) that was mainly populated and the lifetime of the state.For the Fe(III) carbene complexes investigated, there was instead one dominating charge-transfer excited state that was rather unaffected by changes to the ligand. Furthermore, for the Fe(II) complexes metal-centred states played a large role in the deactivation pathway but for the Fe(III) complexes this was not the case.Also, one Co(III) carbene complex was investigated which displays remarkable long lifetime and emission from a metal-centred state.As a first step towards application, the electron-transfer properties of some of the photosensitisers were investigated.Fe(II) complexes with a push-pull design were able to transfer electrons to TiO2 in a solar cell configuration.The solar cell performance was however limited by an ultrafast recombination reaction, that brought a majority of the transferred electrons back to the photosensitiser.The Fe(III) complexes investigated had long enough lifetime to participate in electron transfer with other molecules in solution, if the concentration was high.Furthermore, at very high concentrations of the photosensitiser a light-induced charge-disproportionation reaction outcompeted all other deactivation pathways. In a heterogeneous catalysis configuration, this reaction could generate long-lived Fe(IV) species with the correct additives.The thesis work thus provide fundamental insights to the early implementations of Fe carbene photosensitisers in applications, by resolving key electron-transfer processes on the ultrafast timescale

Competing dynamics of intramolecular deactivation and bimolecular charge transfer processes in luminescent Fe( iii ) N-heterocyclic carbene complexes

Steady state and ultrafast spectroscopy on [Fe$^{III}$(phtmeimb)$_{2}$]PF$_{6}$ (phtmeimb = phenyl(tris(3-methylimidazol-2-ylidene))borate) was performed over a broad range of temperatures. The intramolecular deactivation dynamics of the luminescent doublet ligand-to-metal charge-transfer ($^{2}$LMCT) state was established based on Arrhenius analysis, indicating the direct deactivation of the $^{2}$LMCT state to the doublet ground state as a key limitation to the lifetime. In selected solvent environments photoinduced disproportionation generating short-lived Fe(IV) and Fe(II) complex pairs that subsequently undergo bimolecular recombination was observed. The forward charge separation process is found to be temperature-independent with a rate of ∼1 ps$^{–1}$. Subsequent charge recombination takes place in the inverted Marcus region with an effective barrier of 60 meV (483 cm$^{–1}$). Overall, the photoinduced intermolecular charge separation efficiently outcompetes the intramolecular deactivation over a broad range of temperatures, highlighting the potential of [Fe$^{III}$(phtmeimb)$_{2}$]PF$_{6}$ to perform photocatalytic bimolecular reactions

Djurs påverkan på människors återhämtning från psykisk ohälsa - en narrativ studie på en hästgård

Forskning som har undersökt hur djur påverkar människan har funnits i många årtionden, men det var först under 1900-talets sista decennier som området expanderade kraftigt. Många vetenskapliga discipliner har intresserat sig för ämnet och det finns en hel del forskning kring djurs inverkan på människans välbefinnande och mående. Syftet med vår uppsats var att undersöka hur människor som har återhämtat sig från psykisk ohälsa konstruerar berättelser om den processen i relation till djur. Vi har genomfört fyra kvalitativa intervjuer med kvinnor som haft någon form av psykisk ohälsa och som i sin återhämtningsprocess spenderat tid på en hästgård. Vi har också genomfört deltagande observationer på denna gård som vi sedan har använt i vår analys. Dessutom har vi intervjuat kvinnan som äger och driver verksamheten. På gården bedrivs ingen formaliserad behandling utan det är snarare en form av fristad för personer som är inne i en återhämtningsprocess. Genom hela uppsatsarbetet har vi använt ett narrativt förhållningssätt. Det innebär att vi har fokuserat på berättelser och bland annat konstruerat vår intervjuguide utifrån detta. De viktigaste resultaten och slutsatserna i vår uppsats är att djuren bidrar till en känsla av kravlöshet som kan hjälpa människor att återhämta sig från psykisk ohälsa. Något som också har bidragit till återhämtning är att djuren har fungerat som träningspartners vad gäller bland annat ledarskap. Tillsammans med djuren har man kunnat bygga upp självkänsla och självförtroende. De har också gett motivation, tydlighet och struktur. Vi har sett att djuren i kombination med den specifika miljön på gården har en positiv inverkan på återhämtningsprocessen

Community house, Sandviken - A meeting place by the water

Vid skapandet av Folkets hus i Sandviken var det viktigt för mig att utgå från behovet av mötesplatser och att göra vattnet tillgängligt för alla boende och besökande i området. Ångbåtsbryggan som Sandviken i sin tid växte fram utifrån fick bli utgångspunkt och en rektangulär mötesplats som sträcker sig ut i vattnet blev skapad med inramningen av sex huskroppar. Gestaltningen är utarbetad med inspiration från de gamla tegelbruken som fanns här tidigare, men även den fragmentariska bebyggelse som härskar i Sandviken på grund av den begränsande detaljplanen. Det var även viktigt för mig att inte skapa en för stor byggnad som skulle ta över det pittoreska utseendet på platsen, istället ville jag skapa möjlighet för besökarna att själva kunna använda vissa funktioner utan att huset är bemannat. Platsen mellan byggnaderna delas av den passerande bilvägen och bildar två torg för bygden att samlas kring och tillgängliggör och skapar på så sätt ett Sandviken där fler är välkomna. When creating the community house in Sandviken, it was important for me to start from the need of places to meet and to make the water available to all residents and visitors in the area. The steamboat pier, that Sandviken in its time was founded out from, became the starting point for the project and a rectangular meeting place that extends into the water was created with the framing of six house bodies. The design is made with inspiration from the old brickworks that existed in the region before, but also the fragmentary buildings that rule in Sandviken due to the restrictive detailed plan. It was also important for me not to create an oversized building that would take over the picturesque appearance of the place, instead I wanted to create the opportunity for visitors to be able to use certain functions themselves without the house being staffed. The space between the buildings is divided by the passing car road and forms two squares for the neighborhood to gather around and makes accessible and thus creates a Sandviken where more people are welcome

Community house, Sandviken - A meeting place by the water

Vid skapandet av Folkets hus i Sandviken var det viktigt för mig att utgå från behovet av mötesplatser och att göra vattnet tillgängligt för alla boende och besökande i området. Ångbåtsbryggan som Sandviken i sin tid växte fram utifrån fick bli utgångspunkt och en rektangulär mötesplats som sträcker sig ut i vattnet blev skapad med inramningen av sex huskroppar. Gestaltningen är utarbetad med inspiration från de gamla tegelbruken som fanns här tidigare, men även den fragmentariska bebyggelse som härskar i Sandviken på grund av den begränsande detaljplanen. Det var även viktigt för mig att inte skapa en för stor byggnad som skulle ta över det pittoreska utseendet på platsen, istället ville jag skapa möjlighet för besökarna att själva kunna använda vissa funktioner utan att huset är bemannat. Platsen mellan byggnaderna delas av den passerande bilvägen och bildar två torg för bygden att samlas kring och tillgängliggör och skapar på så sätt ett Sandviken där fler är välkomna. When creating the community house in Sandviken, it was important for me to start from the need of places to meet and to make the water available to all residents and visitors in the area. The steamboat pier, that Sandviken in its time was founded out from, became the starting point for the project and a rectangular meeting place that extends into the water was created with the framing of six house bodies. The design is made with inspiration from the old brickworks that existed in the region before, but also the fragmentary buildings that rule in Sandviken due to the restrictive detailed plan. It was also important for me not to create an oversized building that would take over the picturesque appearance of the place, instead I wanted to create the opportunity for visitors to be able to use certain functions themselves without the house being staffed. The space between the buildings is divided by the passing car road and forms two squares for the neighborhood to gather around and makes accessible and thus creates a Sandviken where more people are welcome

Iron-Based Dye-Sensitized Solar Cells - From Theory to Working Solar Cell

In the hunt for fossile-free energy-harvesting techniques, solar cells constitute one of the most promising techniques. Today, silicon-based solar cells are the dominant technique on the market but even the Silicon solar cell has limitations which means that there is a motivation for developing new solutions. One of those techniques is the dye-sensitized solar cell. Just as in photosynthesis, the solar cell contains a dye molecule that when absorbing the light from the sun can separate an electron from an electron hole. The electron is injected into titania and from there extracted as current. In this Master's thesis, two new dye molecules called FeCAB26 and FeCABCN2 have been investigated by spectroscopic methods (absorption spectroscopy, emission spectroscopy and transient absorption spectroscopy), quantum-chemical calculations and electrical measurements with the purpose to investigate the potential for usage as sensitizers in dye-sensitized solar cells. The molecules are iron-carbene-complexes, synthesized by colleges at Lund University, which are at the frontier of this research field since many traditionally used sensitizers have been ruthenium-complexes. Both molecules were able to sensitize films of titania and absorb light in the visible part of the spectrum. Quantum-chemical calculations indicated that the molecules did excite an electron from metal-centred orbitals to ligand-centred orbitals upon absorption of light. The molecules did also inject electrons into titania via the excited metal-to-ligand charge transfer state. The excited states had lifetimes of 21 ps and 36 ps for the different molecules. When the dye molecules were used as sensitizers in solar cells, a photocurrent was measured upon illumination in a solar simulator for the molecule FeCABCN2. Without having optimized the fabrication process, the efficiency of the best solar cell was 0.13 %. This shows a proof of concept that FeCABCN2 could work as a sensitizer in DSSCs. The optical characterization of both molecules will contribute to the development of iron-carbene-complexes as dye molecules to be used for applications in a broader context than just solar cells.I jakten på förnyelsebara energikällor är solceller en av de mest lovande teknikerna. Idag dominerar kisel-solcellen marknaden men även den har begränsningar och därför är det motiverat att utveckla andra sorters solceller. En solcellsteknik på utvecklingsstadiet som försöker efterlikna fotosyntesen är Grätzelsolcellen. Precis som i fotosyntesen är det en färgämnesmolekyl i solcellen som ska absorbera solens ljus och separera en elektron från ett elektronhål genom att elektronen skickas från färgämnesmolekylen till en titandioxid-elektrod och därifrån extraheras som elektrisk ström. I detta masterarbete har två nya färgämnesmolekyler kallade FeCAB26 och FeCABCN2 undersökts genom en rad spektroskopiska (absorptionsspektroskopi, emissionsspektroskopi, tidsupplöst laserspektroskopi), beräkningskemiska och elektriska mätmetoder med målet att bestämma deras fotofysiska egenskaper och bedöma dugligheten för bruk i Grätzelsolceller. Färgämnesmolekylerna är båda järnkarben-komplex, syntetiserade av kollegor vid Lunds universitet, vilka är i framkanten av forskningen inom detta fält där många metallbaserade färgämnesmolekyler annars varit rutenium-komplex. Båda molekylerna visade sig fästa till titandioxidytor och absorbera ljus i det synliga våglängdsområdet. De kvantkemiska beräkningarna indikerade att färgämnesmolekylerna vid absorption av ljus exciterade en elektron i en metall-centrerad orbital till ligand-centrerade orbitaler. De exciterade tillstånden hade livstider på 21 ps respektive 36 ps. Färgämnesmolekylerna visade sig även injicera elektroner i titandioxiden vid belysning. När färgämnesmolekylerna införlivades i solceller, så kunde en elektrisk ström mätas under belysning i solsimulator för FeCABCN2. Utan att ha optimerat tillverkningsprocessen var effekten för de bästa solcellerna med FeCABCN2 runt 0,13 %. Som ett första steg visar detta att FeCABCN2-färgämnet principiellt sett fungerar, även om fortsatt utveckling mot bättre solceller av denna typ kräver omfattande fortsatt forskning. Karaktäriseringen av båda molekylernas optiska egenskaper bidrar även till den fortsatta utvecklingen av järnkarben-komplex som färgämnesmolekyler mer generellt.Solar energy is a renewable energy source harvested by solar cells. But even if there are functioning solar cells on the market, the hunt for even better ones are engaging many scientists. This project has contributed in the development of a solar cell inspired by nature, that is using simple compounds to form the versatile solar cell of tomorrow: a solar cell that is environmentally friendly, can have different colours and can be made bendable

Being a woman with autism spectrum disorder : A qualitative literature study of the experience of living with ASD and its influence on self-image

Being a woman and living with autism spectrum disorder (ASD) involves double difficulties. Women need to put up with gender-normative demands on how women should be and women with ASD also face difficulties when trying to live “as others”, despite their symptoms. In this thesis we aim to, from an intersectional perspective, study how women with ASD handle gender-normative demands in combination with the maintenance of a good self-image and relationships with others. Our study is a qualitative literature study in which the empirics are based on autobiographies written by, or in collaboration with, women with ASD. The results, concerning the difficulties that women with ASD face, go hand in hand with what previous studies show; women with ASD are shown to mask and imitate their surroundings and theirself-image often change when being diagnosed. Our addition to previous studies is the critical approach to how researchers refer to and study women with functional variation. We find a unilateral perspective insufficient and stress that an intersectional perspective is needed to understand the difficulties women with ASD face. Functional variation or gender alone does not give a full perspective. In our study we therefore have an intersectional, multidimensional, perspective and show that the difficulties women with ASD experience are not only related to their diagnosis but also to their gender

The Human as the Center of Everything in Social Work : A Discourse Analysis of the Swedish National Board of Health and Welfare´s Portrayals of Non-human Animals

Mot bakgrund av tidigare forskning om antropocentriskt socialt arbete avser detta examensarbete att analysera hur Socialstyrelsens policytexter och dokument upprätthåller och utmanar antropocentrismen i socialt arbete. Detta kvalitativa examensarbete har med en integrerad diskursanalytisk metod analyserat diskursiva framställningar av icke-mänskliga djur i förhållande till människor i Socialstyrelsens texter. Post-antropocentrism har använts som teoretisk tolkningsram. Resultatet visar att när det icke-mänskliga djuret står i förhållande till en människa med närhet till antropos (människa med hög status) så upprätthålls antropocentrismen i socialt arbete. När ett icke-mänskligt djur är i förhållande till en människa med distans till antropos (människa med låg status) så utmanas antropocentrismen i socialt arbete. Analysen har föranlett en modell för att visualisera resultatet. Examensarbetet föreslår implikationer för framtida våldsforskning att vidare studera icke-mänskliga djur i förhållande till människor. Drawing on previous research on human-centered social work, this thesis aims to analyze how the Swedish National Board of Health and Welfare (Socialstyrelsen) reproduces and challenges anthropocentrism in social work. Using an integrated discourse analysis as method, this qualitative thesis analyzes how non-human animals are discursively constructed in relation to humans. Post-anthropocentrism has been used as a theoretical framework. Our findings showthat when the non-human animal is depicted in relation to a human with proximity to anthropos (human with high status), anthropocentrism in social work is maintained. Conversely, when a non-human animal is depicted in relation to a human with distance from anthropos (human withlow status), anthropocentrism in social work is challenged. The analysis has led to the development of a model to visualize the results. The thesis suggests implications for future research on violence, to further study non-human animals in relation to humans

Viking Spectrophotometer : A Home-Built, Simple, and Cost-Efficient Absorption and Fluorescence Spectrophotometer for Education in Chemistry

Investigating the optical properties of various chemical compounds using UV-vis spectrophotometers is an essential part of education in chemistry. However, commercial spectrophotometers are usually treated as "magic black boxes", where the dominant majority of optical elements are hidden "under the hood". This often limits understanding of the mechanisms behind the generation of spectral curves, which in turn may impede the ability to understand the limitations of the applied method and, in some cases, interpret the acquired data. In addition, the study of optical emission phenomena using fluorescence spectrophotometers is seldom implemented in educational laboratories due to the practical challenges and costs of the devices, which severely limit pedagogic access to this topic. For students to be more confident with these two basic spectroscopy techniques, we have developed a laboratory kit that provides a multifaceted learning experience. Starting with a basic exploration of an instrument assembly, it teaches, for example, such technical concepts as spectral resolution and detection sensitivity. More fundamentally, it enables deeper learning of the Beer-Lambert law and the notion of Stokes shift. The spectrophotometer is built from cost-efficient materials and is easily scalable, making it affordable for many educational laboratories. Due to a modular design, it is adaptable to various levels of education and has been successfully applied during high school-, undergraduate-, and graduate-level classes

Photophysics and photochemistry of iron carbene complexes for solar energy conversion and photocatalysis

Earth-abundant first row transition metal complexes are important for the development of large-scale photocatalytic and solar energy conversion applications. Coordination compounds based on iron are especially interesting, as iron is the most common transition metal element in the Earth’s crust. Unfortunately, iron-polypyridyl and related traditional iron-based complexes generally suffer from poor excited state properties, including short excited-state lifetimes, that make them unsuitable for most light-driven applications. Iron carbene complexes have emerged in the last decade as a new class of coordination compounds with significantly improved photophysical and photochemical properties, that make them attractive candidates for a range of light-driven applications. Specific aspects of the photophysics and photochemistry of these iron carbenes discussed here include long-lived excited state lifetimes of charge transfer excited states, capabilities to act as photosensitizers in solar energy conversion applications like dye-sensitized solar cells, as well as recent demonstrations of promising progress towards driving photoredox and photocatalytic processes. Complementary advances towards photofunctional systems with both Fe(II) complexes featuring metal-to-ligand charge transfer excited states, and Fe(III) complexes displaying ligand-to-metal charge transfer excited states are discussed. Finally, we outline emerging opportunities to utilize the improved photochemical properties of iron carbenes and related complexes for photovoltaic, photoelectrochemical and photocatalytic applications