Dong, Yu and Sukhanov, Andrey A. and Zhao, Jianzhang and Elmali, Ayhan and Li, Xiaolian and Dick, Bernhard and Karatay, Ahmet and Voronkova, Violeta K. (2019) Spin-Orbit Charge-Transfer Intersystem Crossing (SOCT-ISC) in Bodipy-Phenoxazine Dyads: Effect of Chromophore Orientation and Conformation Restriction on the Photophysical Properties. JOURNAL OF PHYSICAL CHEMISTRY C, 123 (37). pp. 22793-22811. ISSN 1932-7447, 1932-7455
Full text not available from this repository. (Request a copy)Abstract
The spin-orbit charge-transfer-induced intersystem crossing (SOCT-ISC) in Bodipy-phenoxazine (BDP-PXZ) compact electron-donor/-acceptor dyads was studied. PXZ is the electron donor, and BDP is the electron acceptor. The molecular geometry is varied by applying different steric hindrance on the rotation about the linker between the two subunits. Charge-transfer (CT) absorption bands were observed for the dyads with more coplanar geometry (electronic coupling matrix elements is up to 2580 cm(-1)). Ultrafast charge separation (0.4 ps) and slow charge recombination (3.8 ns, i.e., SOCT-ISC process) were observed. Efficient ISC (phi(T) = 54%) and long triplet state lifetime (tau(T) = 539 mu s) were observed for the dyads. Notably, the triplet-state lifetime is 2-fold of that accessed with heavy-atom effect, indicating the advantage of using a heavy-atom-free photosensitizer. The low-lying CT state in the dyads in polar solvents was confirmed with intermolecular triplet photosensitizing method. Time-resolved electron paramagnetic resonance spectroscopy show that the electron spin polarization of the triplet state formed by the SOCT-ISC is the same as that of spin-orbit-ISC (SO-ISC). (CT)-C-3 and localized excited triplet states ((LE)-L-3) were simultaneously observed for one of the dyads, which is rare. Normally, the CT state was observed as spin correlated radical pair. The dyads were used as triplet photosensitizers for triplet-triplet annihilation upconversion, the quantum yield is up to 12.3%. A large anti-Stokes shift (5905 cm(-1)) was achieved by excitation into the CT absorption band, not the conventional LE absorption band.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRIPLET-TRIPLET ANNIHILATION; PHOTON UP-CONVERSION; INTRAMOLECULAR PHOTOREDUCTION PROCESS; PHOTOINDUCED ELECTRON-TRANSFER; PICOSECOND LASER PHOTOLYSIS; SINGLET OXYGEN GENERATION; TIME-RESOLVED EPR; STATE FORMATION; EXCITED-STATES; ANTHRACENE DYADS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 30 Mar 2020 06:58 |
| Last Modified: | 06 Apr 2020 06:32 |
| URI: | https://pred.uni-regensburg.de/id/eprint/26234 |
Actions (login required)
 |
View Item |
