@phdthesis{Strauss2023,
  author    = {Strauß, Volker},
  title     = {Laser-induced carbonization - from fundamentals to applications},
  doi       = {10.25932/publishup-59199},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-591995},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VIII, 78, A245},
  year      = {2023},
  abstract  = {Fabricating electronic devices from natural, renewable resources has been a common goal in engineering and materials science for many years. In this regard, carbon is of special significance due to its biological compatibility. In the laboratory, carbonized materials and their composites have been proven as promising solutions for a range of future applications in electronics, optoelectronics, or catalytic systems. On the industrial scale, however, their application is inhibited by tedious and expensive preparation processes and a lack of control over the processing and material parameters. Therefore, we are exploring new concepts for the direct utilization of functional carbonized materials in electronic applications. In particular, laser-induced carbonization (carbon laser-patterning (CLaP)) is emerging as a new tool for the precise and selective synthesis of functional carbon-based materials for flexible on-chip applications. We developed an integrated approach for on-the-spot laser-induced synthesis of flexible, carbonized films with specific functionalities. To this end, we design versatile precursor inks made from naturally abundant starting compounds and reactants to cast films which are carbonized with an infrared laser to obtain functional patterns of conductive porous carbon networks. In our studies we obtained deep mechanistic insights into the formation process and the microstructure of laser-patterned carbons (LP-C). We shed light on the kinetic reaction mechanism based on the interplay between the precursor properties and the reaction conditions. Furthermore, we investigated the use of porogens, additives, and reactants to provide a toolbox for the chemical and physical fine-tuning of the electronic and surface properties and the targeted integration of functional sites into the carbon network. Based on this knowledge, we developed prototype resistive chemical and mechanical sensors. In further studies, we show the applicability of LP-C as electrode materials in electrocatalytic and charge-storage applications. To put our findings into a common perspective, our results are embedded into the context of general carbonization strategies, fundamentals of laser-induced materials processing, and a broad literature review on state-of-the-art laser-carbonization, in the general part.},
  language  = {en}
}
@article{StraussWangDelacroixetal.2020,
  author    = {Strauss, Volker and Wang, Huize and Delacroix, Simon and Ledendecker, Marc and Wessig, Pablo},
  title     = {Carbon nanodots revised},
  series = {Chemical science},
  volume    = {11},
  journal   = {Chemical science},
  number    = {31},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2041-6520},
  doi       = {10.1039/d0sc01605e},
  pages     = {8256 -- 8266},
  year      = {2020},
  abstract  = {Luminescent compounds obtained from the thermal reaction of citric acid and urea have been studied and utilized in different applications in the past few years. The identified reaction products range from carbon nitrides over graphitic carbon to distinct molecular fluorophores. On the other hand, the solid, non-fluorescent reaction product produced at higher temperatures has been found to be a valuable precursor for the CO2-laser-assisted carbonization reaction in carbon laser-patterning. This work addresses the question of structural identification of both, the fluorescent and non-fluorescent reaction products obtained in the thermal reaction of citric acid and urea. The reaction products produced during autoclave-microwave reactions in the melt were thoroughly investigated as a function of the reaction temperature and the reaction products were subsequently separated by a series of solvent extractions and column chromatography. The evolution of a green molecular fluorophore, namely HPPT, was confirmed and a full characterization study on its structure and photophysical properties was conducted. The additional blue fluorescence is attributed to oligomeric ureas, which was confirmed by complementary optical and structural characterization. These two components form strong hydrogen-bond networks which eventually react to form solid, semi-crystalline particles with a size of similar to 7 nm and an elemental composition of 46\% C, 22\% N, and 29\% O. The structural features and properties of all three main components were investigated in a comprehensive characterization study.},
  language  = {en}
}