Speaker: Prof. Frank Würthner,German National Academy of Science Leopoldina and the Bavarian Academy of Sciences
Time: 10:00, October 14, 2019
Venue:Room N308A, Building of State Key Laboratory of Luminescent Materials and Devices, Wushan Campus
Abstract:
In recent years we could witness a shift of paradigm in organic semiconductor research towards dyes and color pigments. Thus, after two decades of research focused on conjugated polymers and oligothiophene as well as acene based organic semiconductor molecules most recent work in several laboratories demonstrated high charge carrier mobilities > 1 cm2V-1s-1 for various classes of dyes and pigments. These results are remarkable owing to the presence of dipolar functional groups in these compounds which was believed to result in large reorganization energies and bad transport properties. Obviously this view needs to be reassessed. In particular for organic photovoltaics the success of several low band gap conjugated oligomers and polymers (containing dipolar functional groups) as well as small molecule based organic colorants appears highly promising.
In this lecture I will give an overview on our work on n-type organic semiconductors based on naphthalene and perylene bisimides and p-type organic semiconductors based on merocyanines, squaraines and diketopyrrolopyrroles. A particular focus will be given on the most unusual highly dipolar merocyanine dyes which exhibit outstanding performance in bulk heterojunction solar cells with PCE > 6%. Our recent demonstration of hole mobilities up to 1.3 cm2V-1s-1 in organic thin film devices and up to 8.6 cm2V-1s-1 in organic single crystals clearly corroborates the view that the presence of dipolar groups does not imply bad transport properties. Dyes and colorants are accordingly very versatile for organic electronics and organic photovoltaics.
Biography: Frank Würthner received his education in Chemistry at the University of Stuttgart (doctoral degree 1994) and carried out postdoctoral research at MIT in Cambridge/MA (USA). After two years at BASF and five years at the University of Ulm (Habilitation in 2001) he became chair professor of Organic Chemistry at the University of Würzburg in 2002. Here he has served as head of the Institute of Organic Chemistry, dean of the Chemistry Department and founding director of the Center for Nanosystems Chemistry. His main research interests include the synthesis of pi-conjugated molecules and functional dyes, their application in organic electronics, photonics and photovoltaics, the construction of complex supramolecular architectures composed of pi-scaffolds, the mechanistic elucidation of self-assembly processes, and the investigation of light-induced processes in dye-based nanosystems. He has published more than 400 papers and is listed since 2014 regularly among the highly cited chemists of the last decade. He is an elected member of the German National Academy of Science Leopoldina and the Bavarian Academy of Sciences, as well as a Fellow of the Royal Society of Chemistry. His awards include the Arnold-Sommerfeld-Prize of the Bavarian Academy of Science (2002), the Elhuyar-Goldschmidt Award of the Royal Society of Spain (2016) and the Ta-Shue Chou Lectureship Award of Academia Sinica (2018). Since 2016 he is Associate Editor or Organic Chemistry Frontiers.
