Switch of the magnetic field effect on photon upconversion based on sensitized triplet-triplet annihilation

Yonemura, Hiroaki; Naka, Yasuhito; Nishino, Mitsuhiko; Sakaguchi, Hiroshi; Yamada, S.

doi:10.1039/c6pp00264a

Cited by 11 publications

(21 citation statements)

References 38 publications

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“…The magnetic field effect (MFE %) is defined as MFE % = (( I – I 0 )/ I 0 ) × 100%, where I and I 0 are the integrated upconverted emission intensities in the presence and absence of magnetic field, respectively. The MFE % for DPA reaches about −2.0% at 326 mT, which is similar to previous reports. , For the dimers, the MFE % reaches approximately −2.8, −3.2, and −2.6% for o-, m-, and p-dimer, respectively.…”

Section: Results and Discussionsupporting

confidence: 91%

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Intramolecular Versus Intermolecular Triplet Fusion in Multichromophoric Photochemical Upconversion

et al. 2019

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Photon upconversion is a process that creates high-energy photons under low photon energy excitation. The effect of molecular geometry on the triplet fusion upconversion process has been investigated in this work through the design and synthesis of four new 9,10-diphenylanthracene (DPA) derivatives by employing platinum octaethylporphyrin as the triplet sensitizer. These new emitter molecules containing multiple DPA subunits linked together via a central benzene core exhibit high fluorescence quantum yields. Interestingly, large differences in the triplet fusion upconversion performance were observed between the derivatives with the meta-substituted dimer showing the closest performance to the DPA reference. The differences are discussed in terms of the statistical probability for obtaining a high-energy singlet excited state from triplet fusion, f, for both inter- and intramolecular processes and the effect of magnetic field on the upconversion efficiency. These results demonstrate the challenges to be overcome in improving triplet fusion upconversion efficiency based on multichromophoric emitter systems.

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Section: Results and Discussionsupporting

confidence: 91%

“…The MFE % for DPA reaches about −2.0% at 326 mT, which is similar to previous reports. 35,39 For the dimers, the MFE % reaches approximately −2.8, −3.2, and −2.6% for o-, m-, and p-dimer, respectively.…”

Section: ■ Introductionmentioning

confidence: 98%

Intramolecular Versus Intermolecular Triplet Fusion in Multichromophoric Photochemical Upconversion

et al. 2019

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“…[28] While less frequently employed, several studies have confirmed this effect across multiple annihilators and further validate a bimolecular triplet quenching mechanism. [29,30]…”

Section: Introductionmentioning

confidence: 99%

Applications and Prospects for Triplet–Triplet Annihilation Photon Upconversion

Rauch

Knowles²

2018

Chimia

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Triplet-triplet annihilation photon upconversion (TTA-UC) is a photophysical process in which the energy of two photons are combined into a single photon of higher energy. While this strategy has been recognized in applications ranging from bioimaging to solar energy conversion, its uses in synthetic organic chemistry have not been extensively developed. Here, we present a short tutorial on the theoretical underpinnings and the design principles of TTA-UC systems. Selected applications are then discussed to highlight key features of the TTA mechanism, along with a prospective discussion of the potential of these mechanisms to enable innovation in photocatalysis, methods development, and synthetic organic chemistry.

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“…3,8,18−26 However, it is not clear whether T-channel TTA takes place in DPA molecules. 6,15,20,21,27 It is known that the intensity of delayed fluorescence produced by TTA can be modulated by the application of an external magnetic field, 2,28 and TTA processes have been studied with magnetic fields in solid states 2,29−33 and in solutions. 19,21,34−38 The effects of a magnetic field on the delayed fluorescence in crystalline DPA were first reported in the 1970s, with three peaks of fluorescence intensity observed when a magnetic field of 0.5−2.5 T was applied; 2 however, the origin of these peaks has not yet been clarified.…”

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confidence: 99%

Triplet–Triplet Annihilation via the Triplet Channel in Crystalline 9,10-Diphenylanthracene

Yago

Tashiro

Hasegawa

et al. 2022

J. Phys. Chem. Lett.

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Delayed fluorescence resulting from triplet–triplet annihilation in crystalline 9,10-diphenylanthracene was observed by means of steady-state fluorescence measurements under magnetic fields of ≤10 T. At five specific magnetic fields, four peaks and one dip in the magnetic field dependence of fluorescence intensity were observed, proving that exchange-coupled triplet pairs were generated in the course of triplet–triplet annihilation. The dip was in the opposite direction predicted for singlet channel triplet–triplet annihilation. Further analysis using the stochastic Liouville equation confirmed that the closest exchange-coupled triplet pair in crystalline 9,10-diphenylanthracene is quenched via both triplet channel and singlet channel triplet–triplet annihilation.

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Switch of the magnetic field effect on photon upconversion based on sensitized triplet-triplet annihilation

Cited by 11 publications

References 38 publications

Intramolecular Versus Intermolecular Triplet Fusion in Multichromophoric Photochemical Upconversion

Intramolecular Versus Intermolecular Triplet Fusion in Multichromophoric Photochemical Upconversion

Applications and Prospects for Triplet–Triplet Annihilation Photon Upconversion

Triplet–Triplet Annihilation via the Triplet Channel in Crystalline 9,10-Diphenylanthracene

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