Red Thermally Activated Delayed Fluorescence and the Intersystem Crossing Mechanisms in Compact Naphthalimide–Phenothiazine Electron Donor/Acceptor Dyads

Tang, Geliang; Суханов, А. А.; Zhao, Jianzhang; Yang, Wenbo; Wang, Zhijia; Liu, Qingyun; Воронкова, В. К.; Donato, Mariangela Di; Escudero, Daniel; Jacquemin, Denis

doi:10.1021/acs.jpcc.9b09335

Cited by 70 publications

(211 citation statements)

References 106 publications

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“…On the other hand, the RP‐ISC in compact electron donor–acceptor dyads is inhibited, due to the large electronic coupling between the donor and acceptor moieties. However, if the electron donor and acceptor are in orthogonal geometry, the triplet exited state will be populated through spin–orbit charge‐transfer ISC (SOCT‐ISC) [44, 53–57] . In this process, CR between donor and acceptor produces a large change in molecular orbit angular momentum.…”

Section: Introductionmentioning

confidence: 99%

Spin–Orbit Charge‐Transfer Intersystem Crossing in Anthracene–Perylenebisimide Compact Electron Donor–Acceptor Dyads and Triads and Photochemical Dianion Formation

Rehmat

Kurganskii

Mahmood

et al. 2021

Chemistry A European J

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Perylenebisimide (PBI)-anthracene (AN)d onor-acceptor dyads/triad were prepared to investigate spin-orbit charge-transfer intersystem crossing (SOCT-ISC). Molecular conformation was controlled by connecting PBI units to the 2-or 9-position of the AN moiety.S teady-state, time-resolved transient absorption ande mission spectroscopy revealed that chromophore orientation, electronic coupling, and dihedrala ngle between donor and acceptor exert as ignificant effect on the photophysical property.T he dyad PBI-9-AN with orthogonal geometry shows weakg round-state coupling and efficient intersystem crossing (ISC, F D = 86 %) as compared with PBI-2-AN (F D = 57 %), which has am ore coplanar geometry.B yn anosecond transient absorption spectroscopy,along-lived PBI localized triplet state was observed (t T = 139 ms). Time-resolved EPR spectroscopy demonstratedt hat the electron spin polarization pattern of the triplet state is sensitive to the geometry and number of AN units attached to PBI.R eversible and stepwiseg eneration of near-IR-absorbing PBI radical anion (PBI À À•)a nd dianion (PBI 2À À)w as observed on photoexcitation in the presence of triethanolamine, and it was confirmed that selective photoexcitation at the near-IRa bsorption bands of PBIC À À is unable to produce PBI 2À À .

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Section: Introductionmentioning

confidence: 99%

Spin–Orbit Charge‐Transfer Intersystem Crossing in Anthracene–Perylenebisimide Compact Electron Donor–Acceptor Dyads and Triads and Photochemical Dianion Formation

Rehmat

Kurganskii

Mahmood

et al. 2021

Chemistry A European J

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“…[38] In some compact electron donor/acceptor dyads, we observed 3 CT state with time-resolved electron paramagnetic resonance (TREPR) spectroscopy, which is rare. [39,40] Another issue concerning the SOCT-ISC is that although it was proposed that upper triplet state should be involved in the SOCT-ISC, [26] yet no experimental evidence has been reported for this postulate. Hence, much room is left for the investigation of SOCT-ISC and more dyads to unravel the relationship of the dyad molecular structures and the SOCT-ISC efficiency.…”

Section: Introductionmentioning

confidence: 99%

Intersystem Crossing and Electron Spin Selectivity in Anthracene‐Naphthalimide Compact Electron Donor‐Acceptor Dyads Showing Different Geometry and Electronic Coupling Magnitudes

Chen

Kurganskii

Zhang

et al. 2021

Chemistry A European J

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Anthracene-naphthalimide (An-NI) compact electron donor-acceptor dyads were prepared, in which the orientation and distance between the two subunits were varied by direct connection or with intervening phenyl linker. Efficient intersystem crossing (ISC) and long triplet state lifetime (Φ Δ = 92 %, τ T = 438 μs) were observed for the directly connected dyads showing a perpendicular geometry (81°). This efficient spin-orbit charge transfer ISC (SOCT-ISC) takes 376 fs, inhibits the direct charge recombination (CR) to ground state ( 1 CT!S 0 , takes 3.04 ns). Interestingly, efficient SOCT-ISC for dyads with intervening phenyl linker (Φ Δ = 40 % in DCM) was also observed, although the electron donor and acceptor adopt almost coplanar geometry (dihedral angle: 15°). Time-resolved electron paramagnetic resonance (TREPR) spectroscopy shows that the electron spin polarization of the triplet state, i. e. the electron spin selectivity of ISC, is highly dependent on the dihedral angle and the linker. For the dyads showing weaker coupling between the donor and acceptors, the charge separation and the intramolecular triplet energy transfer are inhibited at 80 K (frozen solution), because both the 3 An and 3 NI states were observed and the ESP are same as compared to the native anthracene and naphthalimide, which unravel their origin. The dyads were used as triplet photosensitizers for triplet À triplet annihilation upconversion (TTA UC). High UC quantum yield (Φ UC = 12.9 %) as well as a large anti-Stokes shift (0.72 eV) was attained by excitation into the CT absorption band.

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“…As mentioned earlier, NTO simulations suggested that TrzCNTrx2 includes more CT character, which reduced the Δ E ST and accelerates RISC process. [ 20 ] The TRPL decay curves of the delayed and prompt fluorescence are shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…[ 5–8 ] Whereas, the electron donors have been rather limited as acridine, carbazole, and phenothiazine derivatives. [ 1,8–20 ] Therefore, the development of new electron donors is urgently necessary. Particularly, it is important to develop a donor with a rigid structure because the use of rigid donor moiety was effective to improve EQE and reduce efficiency roll‐off at high luminance.…”

Section: Introductionmentioning

confidence: 99%

Starburst Type Benzofuroindolocarbazole Donor for High Efficiency and Long Lifetime in Thermally Activated Delayed Fluorescence Emitters

Kim

Yoon

Lee

et al. 2020

Advanced Optical Materials

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In many TADF materials, the general molecular structure was a donor-acceptor type structure in order to have a small singlet-triplet energy gap (ΔE ST) value by minimizing the orbital overlap between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) for effective RISC. To date, a lot of TADF materials that feature donor-acceptor structure have been reported by managing the donor and acceptor units, which indicate that the selection of donor and acceptor moieties plays an important role in the TADF emitters. In many papers, the electron acceptors such as diphenyltriazine, diphenylsulphone, pyridine, pyrimidine, etc., have been reported. [5-8] Whereas, the electron donors have been rather limited as acridine, carbazole, and phenothiazine derivatives. [1,8-20] Therefore, the development of new electron donors is urgently necessary. Particularly, it is important to develop a donor with a rigid structure because the use of rigid donor moiety was effective to improve EQE and reduce efficiency roll-off at high luminance. [21] We have already demonstrated that a carbazole derived benzofurocarbazole donor allowed improved TADF performances by the rigidity and strong donor character. [22] This experiment demonstrated the benefits of the rigid donor structure along with other works about rigid donors based on carbazole. [23-25] However, the lifetime and efficiency roll-off of the TADF devices were not satisfactory, which requires the design and development of the even stronger donor than the benzofurocarbazole. In this work, we developed a starburst type rigid donor, benzofuro[3,2-a]indolo[3,2-c]carbazole (Trx), as the donor of the TADF emitters, and two isomeric TADF emitters, 5-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-(15-phenylbenzofuro[3,2-a] indolo[3,2-c]carbazol-10(15H)-yl)benzonitrile (TrzCNTrx1) and 5-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-(10-phenylbenzofuro[3,2-a] indolo[3,2-c]carbazol-15(10H)-yl)benzonitrile (TrzCNTrx2), were synthesized. The Trx was developed as a rigid and strong electron donor for strong charge transfer character in the TADF emitters in combination with a diphenyltriazine electron acceptor and a benzonitrile linker. Thus, the TrzCNTrx1 and TrzCNTrx2 emitters showed a small ΔE ST , high photoluminescence quantum yield, and short exciton lifetimes. In the device application, the

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Red Thermally Activated Delayed Fluorescence and the Intersystem Crossing Mechanisms in Compact Naphthalimide–Phenothiazine Electron Donor/Acceptor Dyads

Cited by 70 publications

References 106 publications

Spin–Orbit Charge‐Transfer Intersystem Crossing in Anthracene–Perylenebisimide Compact Electron Donor–Acceptor Dyads and Triads and Photochemical Dianion Formation

Spin–Orbit Charge‐Transfer Intersystem Crossing in Anthracene–Perylenebisimide Compact Electron Donor–Acceptor Dyads and Triads and Photochemical Dianion Formation

Intersystem Crossing and Electron Spin Selectivity in Anthracene‐Naphthalimide Compact Electron Donor‐Acceptor Dyads Showing Different Geometry and Electronic Coupling Magnitudes

Starburst Type Benzofuroindolocarbazole Donor for High Efficiency and Long Lifetime in Thermally Activated Delayed Fluorescence Emitters

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