Photophysics of nanomaterials for opto-electronic applications
Kahmann, Simon
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Kahmann, S. (2018). Photophysics of nanomaterials for opto-electronic applications. Rijksuniversiteit
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Acknowledgements
This thesis should initially have been titled "Hybrid Solar Cells –New Architectures for More
Effi-cient Devices". It is not. During the first year of my work, I spent a lot of time trying to engineer
hybrid absorption layers, containing colloidal quantum dots and conjugated polymers, in order to improve the efficiency of thin film solar cells, but I did not succeed. In contrast, I developed a real passion for optical spectroscopy. For allowing me to pursue this different focus of work on all these interesting material classes presented here, I shall forever be grateful to my two super-visors, Maria and Christoph.
Maria, I first contacted you, because I wanted to pursue a PhD working with the exciting
col-loidal quantum dots and I wanted to go abroad. From our first encounter on, you have always been more than friendly and supportive. I really appreciated working in your group and I have learnt so much from you about spectroscopy, the different material classes and how to be a pro-per scientist. Your thoughtful guidance and deep insights have helped significantly during the last four years. I shall also forever be thankful to you for having sent me to all these nice confe-rences, already from the beginning of my project. These were true enrichments of my life as a PhD student. Suggesting the binational approach, as you did, furthermore made this endeavour all the more exciting for me and I thank you very much for giving me that opportunity.
Christoph, ever since I went to Erlangen to learn more about organic electronics, I have been
close to your chair. Your inspiring work and approach to science is truly remarkable. I have learnt a lot during and with such an excitement during the last six years, that I shall forever happily look back at this forming time of my life. Working with you was always very easy, despite the more difficult arrangement of a shared supervision. I have always valued your insightful comments and suggestions for my work and hope that I may continue to do so.
Gebi, I’m not sure whether you or I love the FTIR spectrometer more, but I definitely know, I
could not have set-up the technique without you. Your interest in it was highly contagious and I learnt a lot about electrical circuitry and measurement techniques from you. Thank you so much – also for being such a nice office mate.
Andrea, with all your patience, you showed me how the transient absorption set-up works and
how to properly align all the optics. I’m very thankful for these skills and all the insight into
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optical instrumentation that you shared with me. I am also especially grateful for your invitation to Cagliari, where I spent two lovely and productive weeks. I shall happily return if I may.
Arjen, nobody can work in a lab if the equipment is not working and you not only maintained the
set-ups, but you were also often the driving force behind the entertaining lunch conversations. I thank you a lot for all that. Towards the end of my PhD work, also Teo joined the group in Groningen and your presence was a further enrichment both for lunch breaks and the labs. I thank you both very much for allowing me to work in such a nice environment and to share some time with you.
Wolfgang and Misha, you constantly supplied me with high quality CQDs after I had moved back
to Erlangen and I thank you a lot for always being very quick about that. Also, your knowledge about colloidal chemistry and feedback for my work helped me a lot.
Maksym and Loredana, when I started my work on hybrid absorption layers, I have always used
your high quality materials and the communication with you was always very easy and suppor-tive – thank you very much for that good cooperation!
Back when I started my PhD, also a couple of other people did so. Mark, Jorge, Daniel, Vladimir and Artem – we all started within a year and (probably) defend within one. Feeling a stronger connection when going through all these stages in sync is probably inevitable, but your charac-ters made this connection quite a positive one. This also holds for Bart. You have been around from the beginning, first as a master student and later on as a PhD student: All you guys were very supportive, when I had to get accustomed to all the instruments and rules we have in Gro-ningen. Working and having lunch with you was always inspiring and highly entertaining. Also privately, I think, we had a lot of fun crawling through Groningen’s nightlife. Thank you for all those laughs we had.
I have to thank Jorge and Mark, in particular, because the were so kind to become my para-nymphs and walk me down the aisle. Thank you very much for helping me with all the prepara-tions.
Widi and Hong-Hua, you introduced me to the PL set-up and helped me a lot during the early
days of my spectroscopy career. I thank you both a lot for showing me your tips and tricks – it was a pleasure working with you.
Daniele, I thank you very much for the collaboration on the polymer project. Your explanations
significantly helped my understanding of DFT simulations. You were very friendly and suppor-tive through the course of that collaboration and I wish you all the best for the future.
Nicola, we had quite a few interesting discussions about many topics and our collaboration also
turned out quite fruitful. I thank you very much for approaching me with that intriguing ternary system. It was quite a ride, trying to understand it, but all the more rewarding.
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Andres, you were a very pleasant office mate in Erlangen and I have learnt a lot about optics from
you. Thank you very much for all the insight you shared with me.
Giuseppe, the collaboration on our project took much longer than it should have had. This was
due to many different factors, but in the end I think it was worth it. You have been always very accessible to me and your clear explanations of the diffraction data were helpful in understan-ding the power of your measurements.
Cristina, we briefly collaborated on carbon nanotubes for my last project and the discussions
we had were very enlightening. I think your work improved the overall investigation a lot and I thank you very much for your comments and patient explanations of your data.
A great thank you goes to Erdmann Spiecker, who not only heads the Graduiertentenkolleg 1896 that helped me a lot to broaden my scientific understanding, but also contributed to work in this thesis by offering to have TEM micrographs taken from our CQDs. These measurements were carried out by Nadine Schrenker, whom I also sincerely thank for her help and the easy contact we had.
Musty, Sampson, Natasha, Dima, Wytse, Davide, Tejas, Solmaz, I cannot name all the colleagues
that shared time with me working either at iMEET or the POE group, but I would like to sincerely thank you all for your support and your contributions to the good atmosphere I experienced at both sites. It will be hard to find similar environments in the future and you are in a big part responsible for that.
I am furthermore very grateful that Marie-Luise, Beeke and René took so much of their time out of their schedule and helped, with their scanning eyes, to improve the spelling and writing of this long, long text. You were a great help.
There was always one aspect that made travelling in between Erlangen and Groningen challen-ging and this was the question of where to sleep. Looking back, I crashed in so many different places and so many of you friends and colleagues helped me to find shelter. This whole endea-vour would have been so much more complicated if it were not for you. I am also very grateful that I rarely had to undress in return.
A PhD thesis does not come out of nowhere. The ground work for getting where I am now, at least in academia, started almost ten years ago and I have to sincerely thank Peter Hartmann and Hans-Dieter Schnabel for being such inspiring professors during my undergraduate studies. Attending your lectures gave me the solid foundation of skills and understanding that I needed to even consider starting this project. Thank you very much. I still enjoy remembering those days.
On top of this, it was Beatrice, who first showed me how to work scientifically in a proper rese-arch environment and who, with all the patience in the world, showed a young undergraduate
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student the excitement of academic research. I thank you so much.
Abschließend gilt meiner Familie natürlich größter Dank. Ohne zwischendurch zuhause Kraft zu tanken oder wenigstens einen Stopp auf dem Weg zwischen Groningen und Erlangen einlegen zu können, wären die vergangenen vier Jahre sicher nicht so reibungslos verlaufen. Vielen lieben Dank, dass ihr immer für mich da seid.
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