Intramolecular Delayed Fluorescence as a Tool for Imaging Science:  Synthesis and Photophysical Properties of a First-Generation Emitter

Benniston, Andrew C.; Harriman, Anthony; Llarena, Irantzu; Sams, Craig A.

doi:10.1021/cm062525h

Cited by 16 publications

(11 citation statements)

References 119 publications

(75 reference statements)

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“…As shown in Figure a, the similarities between steady-state PL and afterglow emission spectra of m-CDs@nSiO 2 imply their nature of delayed fluorescence (DF). Generally, DF can be divided into three types: E-type DF (emission arising from the lowest singlet excited state (S 1 ) that populated by a reverse intersystem crossing (RISC) from the lowest triplet excited state (T 1 )); ,, P-type DF (triplet–triplet annihilation); and recombination fluorescence (recombination of radical ions or opposite charges) . Among them, the E-type DF or called thermal active delayed fluorescence (TADF) is the most cases of reported and has attracted much attention in recently years due to its high significance in fabricating a new generation of optoelectronic devices. ,,, To make further clarifications, relevance of this afterglow with the triplet excited states is investigated.…”

Section: Resultsmentioning

confidence: 99%

Activating Room Temperature Long Afterglow of Carbon Dots via Covalent Fixation

et al. 2017

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The achievement of long afterglow in aqueous solution and as well as with small effects of dissolved oxygen is critical for its applications, but this is still a highly difficult and challenging task. Herein, a novel strategy for facilely preparing room temperature long afterglow material is reported via covalently fixing carbon dots (CDs) onto colloidal nanosilica (nSiO 2 ). The as-obtained materials (named m-CDs@nSiO 2 ) show not only an unexpected long afterglow emission in water dispersion (lifetime as high as 0.703 s) but also with small effects of the dissolved oxygen. Further studies revealed that the observed long afterglow of m-CDs@nSiO 2 possesses a predominant delayed fluorescence nature and mixed with a portion of phosphorescence. Some key knowledge that can be concluded from this study are (i) covalent interaction could be employed as an option to fix and rigidify triplet emission species; (ii) covalent bonds fixation strategy could behave as a better alternative than that of the frequently used hydrogen/halogen bonds for stabilizing triplets, because this benefits in extending the occurrence of long afterglow from only solid to solution/dispersion forms; and (iii) the containing unsaturated bonds (e.g., CC) on the surface of CDs make them to be self-protection agents from the usual quenching effects of oxygen to the triplets due to their capabilities of reaction with oxygen during the irradiation process. On the basis of the unique long afterglow features of m-CDs@nSiO 2 in water dispersion and oxygen insensitivity, a moisture-related strategy for high-level information protection is proposed and demonstrated.

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Section: Resultsmentioning

confidence: 99%

Activating Room Temperature Long Afterglow of Carbon Dots via Covalent Fixation

et al. 2017

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“…Molecular-scale probes, [7] simply by virtue of their size, have the advantage of being able to enter most cavities, pores and cages but need to be equipped with an appropriate signalling system. Luminescence, in its many disparate forms and including delayed fluorescence, [8] is generally accepted as being a superior signalling method. Indeed, fluorescence can often be transfer process.…”

Section: Introductionmentioning

confidence: 99%

Redox‐Controlled Fluorescence Modulation in a BODIPY‐Quinone Dyad

et al. 2008

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The synthesis and properties of two closely related boron dipyrromethene (BODIPY) derived dyads, incorporating redoxactive quinone units appended at the meso position, are described. For one dyad, the quinone unit is attached directly to the BODIPY core, whereas a phenylene spacer separates the two units in the second compound. Each of the quinone units is readily converted, by both chemical and electrochemical means, to the corresponding hydroquinone derivative. The strong fluorescence normally associated with the BODIPY unit is efficiently quenched in both dyads in their quinone forms. This is attributed to deactivation of the first excited singlet state by a way of an intramolecular electron-

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“…All of the laser flash photolysis studies described above were made with low photon densities to avoid complications from triplet–triplet annihilation. , Such issues have been known to occur with both ZnTPP and FbTPP since the initial studies of Pekkarinen and Linschitz in 1960 . Of late, the concept of triplet–triplet annihilation, leading to P-type delayed fluorescence, , has been considered as a means to improve the performance of certain organic light-emitting diodes . More fundamental research has focused on the maximum yield of delayed fluorescence and the implication for spin-statistical rules. , In deaerated toluene, excitation of both ZnTPP and FbTPP at high laser power (45 mJ/pulse) resulted in a change in the triplet decay kinetics.…”

Section: Results and Discussionmentioning

confidence: 99%

“…75,76 Such issues have been known to occur with both ZnTPP and FbTPP since the initial studies of Pekkarinen and Linschitz in 1960. 32 Of late, the concept of triplet−triplet annihilation, leading to P-type delayed fluorescence, 77,78 has been considered as a means to improve the performance of certain organic light-emitting diodes. 79 More fundamental research has focused on the maximum yield of delayed fluorescence and the implication for spin-statistical rules.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Triplet Distribution in a Symmetrical Zinc(II) Porphyrin–BODIPY Pentameric Array

2020

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A symmetrical molecular array has been synthesized comprising a central zinc(II) 5,10,15,20-tetraphenylporphyrin with identical boron dipyrromethene (BODIPY) units appended at each of the meso sites. Excitation of any subunit causes a cascade of electronic energy-transfer steps, ultimately leading to the BODIPY triplet-excited state in high yield. Coincidentally, the triplet energy levels of the zinc(II) porphyrin and BODIPY appendage are closely balanced such that an equilibrium is established at both 77 K and room temperature. This fast equilibration allows global distribution of the triplet exciton around the array, leading to a significantly increased capture volume for bimolecular quenching and a substantial increase in the rate constant for bimolecular triplet−triplet annihilation. The corresponding free-base porphyrin analogue does not favor triplet exciton decentralization because of the large disparity in the electronic energy levels.

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Intramolecular Delayed Fluorescence as a Tool for Imaging Science: Synthesis and Photophysical Properties of a First-Generation Emitter

Cited by 16 publications

References 119 publications

Activating Room Temperature Long Afterglow of Carbon Dots via Covalent Fixation

Activating Room Temperature Long Afterglow of Carbon Dots via Covalent Fixation

Redox‐Controlled Fluorescence Modulation in a BODIPY‐Quinone Dyad

Triplet Distribution in a Symmetrical Zinc(II) Porphyrin–BODIPY Pentameric Array

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