Physics Seminar: "Structure and Energetics of Organic Semiconductors upon P-doping"

Presented by: Dr. Ingo Salzmann, Dept. of Physics, Chemistry and Biochemistry, Concordia University, Montreal QC

Doping organic semiconductors (OSCs) for enabling new functionality and improving opto-electronic device performance is done by adding strong molecular acceptors as p-dopants to the OSC host. Dr. Salzmann will discuss the broad range of phenomena observed upon molecularly p-doping conjugated polymers (CPs) and molecules (COMs), where two different competing scenarios emerged [1,2]: (i) integer-charge transfer between OSC and dopant forming ion pairs (IPAs), and (ii), partial charge transfer with the emergence of OSC/dopant ground-state charge transfer complexes (CPXs). As prototypical representatives for these two scenarios, IPA formation in F4TCNQ-doped poly(3-hexylthiophene) (P3HT) is juxtaposed to CPX formation found for its parent oligomer, and the respective doping-induced modification of the density of states (DOS) is generally discussed and experimentally assessed by photoelectron spectroscopy. Dr. Salzmann will further focus on the determination of the thin-film structure of COMs/CPs and the modification thereof by molecular doping. Correlating Grazing-incidence X-ray diffraction with infrared spectroscopy for thermally annealed films finally provides insight into the complex growth behavior of p-doped P3HT.

[1] I. Salzmann et al., Acc. Chem. Res. 49, 370 (2016)
[2] H. Méndez et al., Nature Commun. 6, 8560 (2015)


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