title: Ultrafast Excited State Dynamics and Functional Interfaces Probed by Second Harmonic Generation
creator: Hänsel, Marc
subject: ddc-530
subject: 530 Physics
subject: ddc-540
subject: 540 Chemistry and allied sciences
description: Understanding the ultrafast excited state dynamics in organic semiconductors after optical  excitation is a key requisite on the road towards efficient organic solar cells. Additionally,  the creation of functional interfaces built from organic molecular switches  and the read-out of the photochromic state are essential for molecular electronics. In  this thesis, static second harmonic generation (SHG) measurements were utilized to  investigate the photochromism of different indolylfulgimide derivatives immobilized on  silicon. During this, the influence of chemical modifications on the switching efficiencies  (cross-sections) and the non-linear optical contrast between the switching states  were investigated. In the second part of this thesis, femtosecond time-resolved second  harmonic generation measurements were used to investigate the ultrafast decay mechanism  of optically induced electronically excited states in organic semiconductors and  donor/acceptor systems. These led to observations of relaxation into dimer induced  states, charge trapping at native silicon oxide and ultrafast vibronic relaxation. For the  donor/acceptor configurations, depending on the molecular orientation at the interface  and the excitation energy, the creation of charge transfer states were investigated.
date: 2017
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/23703/1/Dissertation_Haensel_2017.pdf
identifier: DOI:10.11588/heidok.00023703
identifier: urn:nbn:de:bsz:16-heidok-237039
identifier:   Hänsel, Marc  (2017) Ultrafast Excited State Dynamics and Functional Interfaces Probed by Second Harmonic Generation.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/23703/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng