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Date/Time: Nov 5, 2025, 13:00-14:00
Venue: Online (Microsoft Teams Webinar)
Lecturer: Prof. Takehiko Mori (Institute of Science Tokyo)
“Quadrupole moments determine crystal structures of organic semiconductors”
Admission:Free Registration:https://events.teams.microsoft.com/event/454e05f0-7e08-441b-81a5-966d2bb253ba@18a7fec8-652f-409b-8369-272d9ce80620
Registration Deadline: Registration will be accepted until just before the seminar starts. After registration, the link for participation will be sent to your registered e-mail address automatically.
【Abstract】 Herringbone (HB) structure, which is widely observed in organic semiconductors, appears due to the electrostatic origin because the quadrupole moment (Q) coming from the −+− charges distributed vertical to the molecular plane, stabilizes a vertical molecular arrangement. Molecules with electron deficient rings have larger Q in the molecular plane than the vertical direction, and realize the stacking structure. A plot of Q is separated to the HB and stacking regions, and the crystal structures are predicted from a molecular property, Q. Such a “phase diagram” is verified by a unit Q model, in which the interplanar distance and the side-on distance associated with the molecular width are important parameters. Naphthalene diimides have the brickwork (BW) structure instead of the HB structure due to the large molecular width, but perylene diimides have the ordinary staking structure owing to the large long-axis Q. Changes of crystal structures in alkyl molecules, and the BW structure in N-containing perylene diimides are explained from Q as well.