123rd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation for Young Physical Chemists I
Room No. Room 305+306
Time THU 09:10-09:19
Code PHYS1.O-2
Subject Ultrafast Solvent-Coupled Charge Transfer in N-annulated Complex with Donor-Acceptor Conjugation
Authors Changwon Kim, Tae Wu Kim1, Chen Li2, Hyotcherl Ihee*
Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
1Chemical Sciences and Engineering, Argonne National Laboratory, United States
2Polymer Research, Max Planck Institute, Germany
Abstract With the development of metal-free donor-acceptor dyes used in dye-sensitized solar cells (DSSCs), understanding the charge transfer character which plays a role in a prior step for electron injection to the electrode in DSSCs is important and the excited-state dynamics in donor-acceptor dyes are widely studied in many fields. Here, we explored the intramolecular charge transfer (ICT) dynamics in the excited state of the diphenylamine N-annulated naphthalene monoimide (DPA-N-NMI) dye, and found that its ICT dynamics shows dependence on the solvent polarity. We characterized its photophysical properties by steady-state absorption/emission spectroscopy and femtosecond broadband transient absorption (TA) spectroscopy, and observed that the transient spectra of the Franck-Condon (FC) state spectrally evolve to the those of the ICT state, which undergoes non-radiative relaxation with conformational rearrangement in polar solvents after photoexcitation. The transition from the FC state to the ICT state and the relaxation of the ICT state within ultrafast time regime are coupled to solvation dynamics, which were identified by extracting the solvation time correlation function. This correlation underlines that the ultrafast charge carrier dynamics is strongly affected by the solvation dynamics dependent on the solvent polarity. The understanding of the ICT dynamics unveiled in this study may offer the comprehensive insights for the carrier dynamics in DSSCs and can contribute to the effective design of dyes.
E-mail cwkim456@gmail.com