A long-term goal within the field of organic electronics has been to developflexible and functional devices, which can be processed and patterned withlow-cost and energy-efficient solution-based methods. This thesis presents anumber of functional paths towards the attainment of this goal via thedevelopment and demonstration of novel fabrication and patterningmethods involving the important organic-semiconductor family termedfullerenes.Fullerenes are soccer-shaped small molecules, with two often-employedexamples being the symmetric C60 molecule and its more soluble derivative[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We show that PCBM canbe photochemically transformed into a dimeric state in a bi-excited reactionprocess, and that the exposed material features a significantly reducedsolubility in common solvents as well as an effectively retained electronmobility. This attractive combination of material properties allows for adirect and resist-free lithographic patterning of electronic PCBM films downto a smallest feature size of 1 µm, using a simple and scalable two-stepprocess constituting light exposure and solution development. In a furtherdevelopment, it was shown that the two-step method was useful also in thearea-selective transformation of fullerene/conjugated-polymer blend films,as demonstrated through the realization of a functional complementary logiccircuit comprising a 5-stage ring oscillator.In another project, we have synthesized highly flexible, single-crystal C60nanorods with a solution-based self-assembly process termed liquid-liquidinterfacial precipitation. The 1-dimensional nanorods can be deposited fromtheir synthesis solution and employed as the active material in field-effecttransistor devices. Here, it was revealed that the as-fabricated nanorods canfeature an impressive electron mobility of 1.0 cm2 V-1 s-1, which is on par withthe performance of a work horse in the transistor field, viz. vacuumdeposited amorphous Si. We further demonstrated that the processability ofthe nanorods can be improved by a tuned light-exposure treatment, duringwhich the nanorod shell is polymerized while the high-mobility interior bulkis left intact. This has the desired consequence that stabile nanoroddispersions can be prepared in a wide range of solvents, and we anticipatethat functional electronic devices based on solution-processable nanorodscan be realized in a near future.

The fast growing production of carbon based nanomaterials (CNMs) and their potential widespread use in consumer products raise concerns regarding their potential risks to human health and ecosystems. The present study investigated the role of photochemical transformation and natural organic matter (NOM) in the fate, transport, and toxicity of fullerenes and carbon nanotubes (CNTs) in natural aquatic systems, providing fundamental information for risk assessment and management. Photochemical transformation of aqueous fullerene nanoparticles (nC60) and CNTs occurs at significant rates under UVA irradiation at intensity similar to that in sunlight. The transformation processes are mediated by self-generated ROS, resulting in changes of surface structure depending on the initial surface oxidation state of CNMs. UVA irradiation leads to oxygenation of nC60 surface and decarboxylation of carboxylated multi-walled carbon nanotubes (COOH-MWNTs). The environmental transport of CNMs is significantly affected by their surface chemistry, concentration and species of electrolytes, and concentration and properties of co-existing NOM. In electrolyte solutions without NOM, the mobility of CNMs is largely decided by their surface chemistry, primarily the oxygen-containing functional groups. In NaCl solutions, UVA irradiation remarkably enhanced the mobility of nC60; conversely, it reduced nC60 stability in CaCl2 solutions. The mobility of COOH-MWNTs in NaCl solutions correlated well with the abundance of surface carboxyl groups. Humic acid, once adsorbed on the nC60 surface, can significantly enhance its stability through steric hindrance. The extent of stabilization depends on the amount and properties of humic acid adsorbed. Humic acid has limited adsorption on UVA-irradiated nC60. Soil humic acid is more efficient in stabilizing nC60 than aquatic humic acid due to its higher molecular weight. Humic acid immobilized onto the silica surface can potential enhance or hinder nC60 deposition, depending on the complex interplay of attractive and repulsive forces. MWNTs are more toxicity to bacteria, Escherichia coli, than COOH-MWNTs due to their higher bioavailability and oxidative capacity. Surface oxidation induced by •OH reduced the toxicity of MWNT while reactions with •OH have little effect on the COOH-MWNT toxicity. Antioxidants such as glutathione can effectively inhibit the antibacterial activity of MWNTs.

Polybrominated dibenzo-p-dioxins (PBDD) and dibenzofurans (PBDF) are a group of compounds of emerging interest as potential environmental stressors. Their structures as well as toxic responses are similar to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. High levels of PBDDs have been found in algae, shellfish, and fish, also from remote areas in theBaltic Sea. This thesis presents studies on PBDD behavior in fish and offspring, and natural formation of PBDDs from naturally abundant phenolic precursors. The uptake, elimination, and maternal transfer of mono- to tetraBDD/Fs were investigated in an exposure study reported in Paper I. The effects of PBDDs in fish were examined in a dose-response study (Paper II). It was shown that fish can assimilate PBDD/Fs from their feed, although non-laterally substituted congeners were rapidly eliminated. Laterally substituted congeners were retained as was congeners without vicinal hydrogens to some extent. PBDD/Fs were transferred to eggs, and congeners that were rapidly eliminated in fish showed a higher transfer ratio to eggs. Exposure to the laterally substituted 2,3,7,8-TeBDD had significant effects on the health, gene expression and several reproduction end-points of zebrafish, even at the lowest dose applied. The geographical and temporal variations of PBDD in biota samples from the Baltic Seasuggest biogenic rather than anthropogenic origin. In Paper III, bromoperoxidase-mediated coupling of 2,4,6-tribromophenol yielded several PBDD congeners, some formed after rearrangement. The overall yield was low, but significantly higher at low temperature, and the product profile obtained was similar to congener profiles found in biota from the Swedish West Coast. In Paper IV, photo­chemi­cally induced cyclization of hydroxylated polybrominated diphenyl ethers under natural conditions produced PBDDs at percentage yield. Rearranged products were not detected, and some abundant congeners do not seem to be formed this way. However, the product profile obtained was similar to congener profiles found in biota from the Baltic Proper. Since the PBDD congeners found in biota have a high turn-over in fish, the exposure must be high and continuous to yield the PBDD levels measured in wild fish. Thus, PBDDs must presumably be formed by common precursors in general processes, such as via enzymatic oxidations, UV-initiated reactions or a combination of both. The presented pathways for formation of PBDDs are both likely sensitive to changes in climatic conditions.