@misc{HoffmannMikaloYfantisetal., author = {Hoffmann, Patrick and Mikalo, Ricardo Pablo and Yfantis, Alexandros D. and Batchelor, David R. and Appel, G{\"u}nter and Schmeißer, Dieter}, title = {A Spectro-Microscopic Approach for Thin Film Analysis Grain Boundaries in mc-Si and Sn/SnO2 Nano Particles}, series = {Microchimica Acta}, volume = {136}, journal = {Microchimica Acta}, number = {3-4}, issn = {1436-5073}, pages = {109 -- 113}, language = {en} } @inproceedings{MikaloAppelHoffmannetal., author = {Mikalo, Ricardo Pablo and Appel, G{\"u}nter and Hoffmann, Patrick and Schmeißer, Dieter}, title = {Conducting Polypyrrole doped with Phthalocyaninesulfonates - new materials for chemical sensors}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Polypyrrole - a conducting polymer - is used as an active electrode of a quartz micro ballance and considered as a gate electrode in all-polymer field effect transistors used as chemical sensor. We use substituted phthalocyanines as dopants of polypyrrole as they offer the possibility to enhance the dopant concentration as well as to include functionalized groups. We studied these films by photoelectron spectroscopy, NEXAFS, PEEM, and TEM. These investigations revealed that the electronic structure as well as the morphology are highly dependent on the dopant's structure. We suggest a new charge transport model for 5-ring heterocycle conductive polymers. Whereas in the standard model only the carbon backbone is considered for the charge transport, we found by NEXAFS investigations that the heteroatom has a considerable high participation in the gap states, which are responsible for the charge transport. The dopants π-interactions force the nitrogen lone pair wave functions to contribute to the conducting polymer π-system. This is a novel approach concerning the application as chemical sensors since the reversible interaction of the analyte modifies the dopant and not the matrix.}, language = {en} } @inproceedings{MikaloAppelHoffmannetal., author = {Mikalo, Ricardo Pablo and Appel, G{\"u}nter and Hoffmann, Patrick and Schmeißer, Dieter}, title = {Leitf{\"a}higes Polypyrrol als Elektrodenmaterial: Wechselwirkungen mit Silber}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Untersuchungen des metallischen Kontaktes von Silber auf tosylat- und phthalocyanindotiertem Polypyrrol wurden mittels XPS- und µ-NEXAFS vorgenommen. Es wurde festgestellt, daß Silber mit dem Polypyrrol keine Verbindung eingeht. Daraus kann geschlossen werden, daß sowohl das leitf{\"a}hige Polymer, als auch das Silber ihren Leitf{\"a}higkeitsmechanismus beibehalten. Es konnte gezeigt werden, daß bei steigender Silberbelegung die Intensit{\"a}t der Polaronenzust{\"a}nde des Polypyrrol in st{\"a}rkerem Maße abnimmt, als die Intensit{\"a}t der unbesetzten Zust{\"a}nde. Das l{\"a}ßt darauf schließen, daß Silber die Grenzfl{\"a}che stabilisiert.}, language = {de} } @misc{HenkelOpreaPaloumpaetal., author = {Henkel, Karsten and Oprea, A. and Paloumpa, Ioanna and Appel, G{\"u}nter and Schmeißer, Dieter and Kamieth, P.}, title = {Selective polypyrrole electrodes for quartz microbalances : NO2 and gas flux sensitivities}, series = {Sensors and Actuators : B, Chemical 76(2001)1-3}, volume = {76}, journal = {Sensors and Actuators : B, Chemical 76(2001)1-3}, number = {1-3}, issn = {0925-4005}, pages = {124 -- 129}, language = {en} } @techreport{HenkelPaloumpaOpreaetal., author = {Henkel, Karsten and Paloumpa, Ioanna and Oprea, A. and Appel, G{\"u}nter and Schmeißer, Dieter and Frandsen, W. and Sch{\"o}lzel, Mario}, title = {Entwicklung von Sensoren mit Elektroden aus leitf{\"a}higen Polymeren}, language = {de} } @article{AppelSchmeisserBaueretal., author = {Appel, G{\"u}nter and Schmeißer, Dieter and Bauer, Jakob and Bauer, Monika and Egelhaaf, H. J. and Oelkrug, D.}, title = {The formation of oligomers in the electrolyte upon polymerization of pyrrole}, language = {en} } @article{YfantisAppelSchmeisseretal., author = {Yfantis, Alexandros D. and Appel, G{\"u}nter and Schmeißer, Dieter and Yfantis, Alexandros D.}, title = {Polypyrrole doped with fluoro-metal complexes: thermal stability and structural properties}, language = {en} } @phdthesis{Appel, author = {Appel, G{\"u}nter}, title = {Untersuchungen zur mesoskopischen und elektronischen Struktur von Polypyrroltosylat und Polypyrrolkupferphthalocyaninsulfonat}, publisher = {Shaker}, address = {Aachen}, isbn = {3-8265-4830-2}, pages = {118}, language = {de} } @article{AppelBoehmeSchmeisser, author = {Appel, G{\"u}nter and B{\"o}hme, O. and Schmeißer, Dieter}, title = {NEXAFS-Spectroscopy of Differently Doped Polypyrroles}, language = {en} } @misc{GuerekAppelMikaloetal., author = {G{\"u}rek, A. G. and Appel, G{\"u}nter and Mikalo, Ricardo Pablo and Schmeißer, Dieter}, title = {Synthesis of dihydroxy silicon phthalocyanine tetrasulfonic acid and poly-µ-oxo silicon phthalocyanine tetrasulfonic acid}, series = {Journal of Porphyrins and Phthalocyanines}, volume = {5}, journal = {Journal of Porphyrins and Phthalocyanines}, number = {10}, issn = {1099-1409}, pages = {751 -- 757}, language = {en} }