Photoinduced Charge Separation of 10-Phenyl-10H-phenothiazine–2-Phenylanthraquinone Dyad Bridged by Bicyclo[2.2.2]octane

Abstract

Photoinduced charge separation of a phenothiazine–anthraquinone dyad 1 with a rigid bicyclo[2.2.2]octane spacer was investigated by means of picosecond and nanosecond transient absorption and time-resolved ESR spectroscopies. Irradiation of the anthraquinone chromophore in 1 produced the charge-separated (CS) state in THF. Time constants of the formation and the decay of the CS state were determined to be 1.3 ns and 1.0 µs, respectively. Time-resolved ESR showed spin-polarized all-emission signals due to the formation of the CS state via the triplet mechanism.

Application of time-resolved electron paramagnetic resonance spectroscopy in the mechanistic study of thermally activated delayed fluorescence (TADF) materials

“…the strong spin-spin interaction between the radical anion and the cation, makes the formation of 1 CT and 3 CT states possible, otherwise only SCRP can be observed (in this case the electron spin-spin interaction is very weak). [70][71][72] Moreover, we observed an evolution of the ESP phase pattern for NI-N-PTZ, the ESP is switched at a longer delay time for the 3 CT state. This phenomenon is probably due to the interconversion of the 3 CT and 3 LE states, and rotation of the ZFS principal axes of the 3 CT 2 3 LE internal conversion, and The molecular structure of the reference compound NI-C-PTZ is also presented.…”

“…the strong spin–spin interaction between the radical anion and the cation, makes the formation of 1 CT and 3 CT states possible, otherwise only SCRP can be observed (in this case the electron spin–spin interaction is very weak). 70–72…”

Red Light‐Emitting Thermally‐Activated Delayed Fluorescence of Naphthalimide‐Phenoxazine Electron Donor‐Acceptor Dyad: Time‐Resolved Optical and Magnetic Spectroscopic Studies

“…This is different from the scenario of the electron donor-acceptor dyads containing long linkers. [32] Based on the above results, we can assign the following species observed in the femtosecond and nanosecond transient absorption spectra.…”

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

“…The efficient conversion of light to storable electric or chemical energy was investigated with a phenothiazineanthraquinone dyad 168 , connected via BCO (Figure ) . The photoinduced charge separation of the dyad was determined through the use of picosecond and nanosecond transient absorption and time‐resolved ESR spectroscopies.…”

“…The efficient conversiono fl ight to storable electric or chemical energy was investigated with ap henothiazineanthraquinone dyad 168,c onnected via BCO ( Figure 16). [218] The photoinducedc harge separation of the dyad was determined throught he use of picosecond and nanosecond transienta bsorptiona nd time-resolved ESR spectroscopies. Al ong-lived charge separated(CS) state wasobserved in the dyad upon excitation of the anthraquinone (AQ) donor chromophore, as AQ acts as at riplet photosensitizer.T ime constantso f1 .3 ns and 1.0 msw ere found of the formation andt he decay of the CS state, respectively.O wing to the formation of the CS state via the triplet mechanism, time-resolved ESR showeds pin polarization for all the emission signals.…”