Herein, we revealed a symmetry-breaking charge transfer (SBCT) process in the excited state of a directly linked push-pull porphyrin dyad (AD) and triad (ADA) via spectroscopic measurements including steady-state absorption and fluorescence, time-resolved fluorescence (TRF), femtosecond transient absorption (fs-TA), and time-resolved infrared (TRIR) measurements. Unprecedented broad fluorescence spectra were observed for porphyrin arrays in polar solvents; these were attributed to the existence of a charge transfer state as evidenced by the TRF measurements. TA measurements also revealed emerging features of a CT state for AD and ADA in polar solvents. These dynamics were also confirmed via TRIR measurements, which provided further information on the solvation and structural relaxation processes of the SBCT process. This is the first observation of an SBCT process in porphyrin arrays, providing fundamental understanding of the strongly coupled porphyrin arrays. Thus, the results of this study reveal the potential of the porphyrin arrays in relevant applications requiring SBCT.
Bibliographical noteFunding Information:
This research was conducted at the University of Yonsei and supported by the Global Research Laboratory Program (2013K1A1A2A02050183) funded by the Ministry of Science, ICT & Future, Korea (D. K.). The quantum mechanical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (KSC-2015-C3-024). The work at Kyoto was supported by the JSPS KAKENHI Grant Numbers 25220802 and 25620031. H. M. acknowledges the JSPS Fellowship for Young Scientists. The work at Busan was supported by the National Research Foundation of Korea (NRF) with a grant funded by the Korea government (MEST) (NRF-2014R1A2A2A01002456, NRF-2014R1A4A1001690).
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry