Electrogenerated Chemiluminescence of Donor–Acceptor Molecules with Thermally Activated Delayed Fluorescence

Ishimatsu, Ryoichi; Matsunami, Shigeyuki; Kasahara, Takashi; Mizuno, Jun; Edura, Tomohiko; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko

doi:10.1002/ange.201402615

Cited by 48 publications

(33 citation statements)

References 30 publications

(26 reference statements)

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“…K is known to destabilize the singlet state, but to stabilize the triplet state. 18 Thus, as a result of the reduction in K, the binding energy of the singlet excimer is further enhanced, while that of the triplet excimer is reduced. This is also consistent with the aforementioned fact that the triplet state has an additional contribution that restores the reduced values of K. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 It is also noteworthy that the effect of the intermolecular interactions on ∆E ST is significantly larger for the anthracene excimer than that of the benzene or naphthalene excimers.…”

Section: K: Singlet Vs Triplet Statesmentioning

confidence: 98%

“…[5][6][7] In addition, recent studies have reported that the molecules with small ∆E ST , so-called thermally activated delayed fluorescent (TADF) molecules, can facilitate intersystem crossing at room temperature, and hence highly efficient electroluminescence can be achieved without the assistance of heavy metal atoms such as Ir or Pt. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The energy difference between singlet and triplet states is usually considered to be twice the exchange energy (K), i.e., 2K. [24][25][26] This holds true only if both singlet and triplet states are of exactly the same nature, and the relaxations of their wavefunctions are neglected.…”

Section: Introductionmentioning

confidence: 99%

“…7 This strategy has also been successfully applied to the design and synthesis of TADF molecules. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] It is well known that intermolecular interactions often exert a significant influence on the intrinsic optical properties of molecules. For example, some Pt-containing blue phosphors, which were reported to emit orange light when forming excimers, were employed for single-dopant white OLEDs.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Intermolecular Interactions on the Singlet–Triplet Energy Difference: A Theoretical Study of the Formation of Excimers in Acene Molecules

Kim

2015

J. Phys. Chem. C

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The effects of intermolecular interactions in the excited state of acene molecules on the singlet-triplet energy difference (∆E ST ) were investigated by carrying out ab initio calculations at the SOS-CIS(D 0 )/aug-cc-pVDZ level. Benzene, naphthalene, and anthracene molecules were employed, and their ∆E ST values were compared with those of their respective cofacial excimers. Our theoretical results demonstrate that, upon the formation of excimer, the ∆E ST values decrease significantly. By carrying out an excitation energy decomposition, we found that ∆E ST , albeit also modulated by the changes in orbital energy difference and coulomb energy, is dominated by the difference in exchange energy between the singlet and triplet states, with the exchange energy decreasing as the intermolecular interactions become stronger. The natural transition orbital analysis suggests that the decrease in the exchange energy may be caused by the different nature of the hole and electron wavefunctions of the excimers (bonding vs anti-bonding), which gives rise to their spatial separation. Furthermore, it was found that the geometry relaxation effects depend on the spin state, thus leading to a further reduction of ∆E ST .

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Section: K: Singlet Vs Triplet Statesmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Intermolecular Interactions on the Singlet–Triplet Energy Difference: A Theoretical Study of the Formation of Excimers in Acene Molecules

Kim

2015

J. Phys. Chem. C

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“…Wang and co‐workers employed the photocatalyst 4CzIPN in the difluoroalkylation of aldehyde‐derived hydrazones via a three‐component coupling of aldehydes ( 244 ), hydrazines ( 245 ) and BrCF 2 CO 2 Et, under irradiation with 8 W blue LEDs . An investigation of the substrate scope for the difluoroalkylation process demonstrated that aldehydes bearing electron‐donating and electron‐withdrawing substituents at ortho ‐, meta ‐, and para ‐positions on the aromatic ring, as well as heterocyclic and aliphatic groups were compatible substrates, providing the corresponding products in moderate to excellent yields ( 246 , Scheme : 22 examples, 41–93% yields).…”

Section: Organic Photocatalyzed Difluoroalkylation Reactionsmentioning

confidence: 99%

Progress in Difluoroalkylation of Organic Substrates by Visible Light Photoredox Catalysis

2019

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Thes electivei ncorporation of fluorinated motifs, in particularC F 2 FG (FG = af unctional group) and CF 2 Hg roups,i ntoo rganic compounds has attrracted increasing attention since organofluorine molecules are of the utmost importance in the areas of nuclear imaging,pharmaceutical, agrochemical, and material sciences.Avariety of synthetic approachesh as been employed in late-stage difluoroalkylationr eactions.V isible light photoredox catalysis for the production of CF 2 FG and CF 2 Hr adicalsh as providedamore sustainable alternative to other conventional radical-triggered reactions from the viewpoint of safety,c ost, availability,a nd "green"c hemistry.Awide range of difluoroalkylating reagents has been successfully implemented in these organic transformationsi nt he presence of transitionm etal complexes or organic photocatalysts.I nmost cases, upon excitation via visible light irradiation with fluorescent light bulbs or blue light-emitting diode (LED) lamps,t hese photocatalysts can act as both reductivea nd oxidative quenchers,t hus enabling the applicationo fe lectron-donoro re lectron-acceptor difluoroalkylating reagents for the generation of CF 2 FG andC F 2 Hr adicals.S ubsequent radical addition to substrates and additional organic transformations affordt he corresponding difluoroalkylatedd erivatives.T he presentr eview describes the distinct strategies for the transitionm etal-and organic-pho-tocatalyzed difluoroalkylation of ab road range of organic substrates by visible light irradiationr eported in the literature since 2014.

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“…Efficient RISC requires singlet-triplet splitting (Δ E ST ) between the first singlet (S 1 ) and triplet (T 1 ) energy levels as small as possible 11 12 13 14 15 16 17 18 19 . In this case, the low-energy singlet charge transfer states ( 1 CT) are commonly utilized on the basis of strong electronic coupling in donor-acceptor (D-A) systems 18 19 20 21 22 23 . However, the employment of D-A structures renders the high molecular polarity and strong intermolecular interactions for TADF dyes, remarkably worsening the quenching effects 24 , e.g.…”

mentioning

confidence: 99%

Optimizing the Intralayer and Interlayer Compatibility for High-Efficiency Blue Thermally Activated Delayed Fluorescence Diodes

Duan

Fan

Wei

et al. 2016

Sci Rep

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A series of phosphine oxide hosts, 4,6-bis(diphenylphosphoryl) dibenzothiophene (DBTDPO) and 4- diphenylphosphoryldibenzothiophene (DBTSPO), and electron transporting materials (ETM), 2-(diphenylphosphoryl)dibenzothiophene sulfone (2DBSOSPO), 3-(diphenylphosphoryl)dibenzothiophene sulfone (3DBSOSPO) and 4-(diphenylphosphoryl)dibenzothiophene sulfone (4DBSOSPO) were developed to support blue thermally activated delayed fluorescence (TADF) devices with high performance through optimizing intralayer and interlayer compatibility of emissive layers. On the basis of the triplet energy of ~3.0 eV for the hosts and ETMs, excitons can be effectively confined on DMAC-DPS. Compared to DBTSPO, DBTDPO can support the excellent distribution uniformity to blue TADF dye bis[4-(9,9-dimethyl–9,10-dihydroacridine) phenyl] sulfone (DMAC-DPS), owing to their configuration similarity; while 3DBSOSPO and 4DBSOSPO are superior in compatibility with the hosts due to the similar molecular polarity or configuration. Through adjusting the molecular configuration, the electrical performance of ETMs can be feasibly tuned, including the excellent electron mobility (μe) by the order of 10−3 cm2 V−1 s−1. As the result, DBTDPO and 4DBSOSPO endowed their four-layer blue TADF devices with the maximum current efficiency of 33.5 cd A−1 and the maximum external quantum efficiency more than 17%, which are impressive among the best blue TADF devices. It is showed that intralayer compatibility determines the maximum efficiencies, while interlayer compatibility influences efficiency stability.

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Electrogenerated Chemiluminescence of Donor–Acceptor Molecules with Thermally Activated Delayed Fluorescence

Cited by 48 publications

References 30 publications

Effects of Intermolecular Interactions on the Singlet–Triplet Energy Difference: A Theoretical Study of the Formation of Excimers in Acene Molecules

Effects of Intermolecular Interactions on the Singlet–Triplet Energy Difference: A Theoretical Study of the Formation of Excimers in Acene Molecules

Progress in Difluoroalkylation of Organic Substrates by Visible Light Photoredox Catalysis

Optimizing the Intralayer and Interlayer Compatibility for High-Efficiency Blue Thermally Activated Delayed Fluorescence Diodes

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