Triplet-to-singlet exciton transfer in hyperfluorescent OLED materials

Sousa, Leonardo Evaristo de; Born, Larissa dos Santos; Neto, Pedro Henrique de Oliveira; Silva, Piotr de

doi:10.1039/d1tc05596h

Cited by 15 publications

(14 citation statements)

References 49 publications

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“…The strict optimization of rISC rates could be relevant for applications such as hyperfluorescence, in which the responsibility for emission is transferred to other molecules. 6 For pure TADF applications, simultaneous optimization of the fluorescence and rISC rates is required. In this case, the best Hamiltonian found (red lines in Figure 6a) has K CT = 0.041 eV.…”

Section: Resultsmentioning

confidence: 99%

Diabatic Decomposition Perspective on the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence

Sousa

Silva

2022

J. Chem. Theory Comput.

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Thermally activated delayed fluorescence (TADF) is a phenomenon that relies on the upconversion of triplet excitons to singlet excitons by means of reverse intersystem crossing (rISC). It has been shown both experimentally and theoretically that the TADF mechanism depends on the interplay between charge transfer and local excitations. However, the difference between the diabatic and adiabatic character of the involved excited states is rarely discussed in the literature. Here we develop a diabatization procedure to implement a four-state model Hamiltonian to a set of TADF molecules. We provide physical interpretations of the Hamiltonian elements and show their dependence on the electronic state of the equilibrium geometry. We also demonstrate how vibrations affect the TADF efficiency by modifying the diabatic decomposition of the molecule. Finally, we provide a simple model that connects the diabatic Hamiltonian to the electronic properties relevant to TADF and show how this relationship translates into different optimization strategies for rISC, fluorescence, and overall TADF performance.

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Section: Resultsmentioning

confidence: 99%

Diabatic Decomposition Perspective on the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence

Sousa

Silva

2022

J. Chem. Theory Comput.

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“…To this end, we have examined the FRET and DET in some pairs of FE/TADF in the hyperfluorescence mechanism. As illustrative examples, two pairs including the FEs and TADF sensitizers, which in turn have previously been investigated in the original experimental work 19 as well as in the recent theoretical studies in the field, 30,31,36 were considered. They are one pair including TBRb and PXZ-TRZ, and another pair composed of TBRb and PPZ-DPO, where for each pair the former plays the role of FE and the latter is the TADF sensitizer.…”

Section: Resultsmentioning

confidence: 99%

“…101–103 Therefore, following previous suggestions in the field, we used the 6-31G(d,p) basis set for the optimal tuning procedures and subsequent computations on the B3LYP/6-31G(d,p) optimized geometries. 31,36,104…”

Section: Computational Detailsmentioning

confidence: 99%

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Toward highly efficient hyperfluorescence-based emitters through excited-states alignment using novel optimally tuned range-separated models

Izadkhast

2022

Phys. Chem. Chem. Phys.

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“…The triplet-singlet energy transfer is widely used to obtain high-efficiency fluorescent organic lightemitting devices [3,11,12], to create biochemical and biophysical sensors [12], and can be used as a method to increase the rate of light emission from excited triplet states [13]. In [11], the authors used nonradiative energy transfer to increase the efficiency of a fluorescent red organic light-emitting device in four times.…”

Section: Introductionmentioning

confidence: 99%

Plasmon effect on triplet-singlet energy transfer in the dye-doped Langmuir-Blodgett films

Temirbayeva¹,

Ibrayev²,

Seliverstova³

et al. 2022

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The effect of silver plasmonic nanoparticles on triplet-singlet energy transfer in the donor-acceptor pair of organic dyes was studied. Layered dye films were prepared on the surface of glass and island silver films using the Langmuir-Blodgett method. Amphiphilic analogs of Rose bengal and polymethine dye were used as donor and acceptor of energy. A polymer monolayer was deposited between monolayers of donor and acceptor molecules to exclude the competing triplet-triplet energy transfer. The spectra of delayed fluorescence and phosphorescence of donor-acceptor films and the delayed luminescence lifetime of donor in these films have been measured. It is shown that a threefold increase in the fluorescence intensity and a twofold increase in the donor phosphorescence intensity are observed on silver island films. The successful triplet-singlet energy transfer is evidenced by both the quenching of donor centers and appearance of sensitized delayed fluorescence of the acceptor with the duration close to the donor triplet lifetime. In the presence of silver nanoparticles, in addition to enhancement in the intensity of the donor emission, an increase in the efficiency of tripletsinglet energy transfer was observed. The obtained results can be used in various optical devices.

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Triplet-to-singlet exciton transfer in hyperfluorescent OLED materials

Abstract: Hyperfluorescent organic light-emitting diodes combine two kinds of dopants to maximize device efficiency: one molecule exhibiting thermally activated delayed fluorescence (TADF) and another molecule with a high fluorescence rate and...

Cited by 15 publications

References 49 publications

Diabatic Decomposition Perspective on the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence

Diabatic Decomposition Perspective on the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence

Toward highly efficient hyperfluorescence-based emitters through excited-states alignment using novel optimally tuned range-separated models

Plasmon effect on triplet-singlet energy transfer in the dye-doped Langmuir-Blodgett films

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