Minimization of solid-state conformational disorder in donor–acceptor TADF compounds

Serevičius, Tomas; Skaisgiris, Rokas; Dodonova, Jelena; Kazlauskas, Karolis; Juršėnas, Saulius; Tumkevičius, Sigitas

doi:10.1039/c9cp05907e

“…The full width half maximum (FWHM) for the simulated curve for Figure 7(a) is ∼0.8 eV while for Figure 7(b) the FWHM is ∼1.1 eV. Such broadening is related to the disorder in the molecular conformations [33] . The molecular conformations that are responsible for the 0‐0 transitions are given in Figure 7(c) and Figure 7(d) for TPA‐TRZ and p TPA‐TRZ respectively.…”

Section: Resultsmentioning

confidence: 96%

“…Such broadening is related to the disorder in the molecular conformations. [33] The molecular conformations that are responsible for the 0-0 transitions are given in Figure 7(c) and Figure 7(d) for TPA-TRZ and pTPA-TRZ respectively. As we can see, because of the weaker interaction for pTPA-TRZ at 300 K, molecules can adopt different preferential orientations at the ground state.…”

Section: (D)mentioning

confidence: 99%

Effect of Bulky Functional Groups on Donor and Acceptor Interactions and their Photoluminescence Properties

Woon

¹

,

Mustapa

²

,

Jamel

³

et al. 2020

ChemPhysChem

4

0

View full text Add to dashboard Cite

Material designs that use donor and acceptor units are often found in organic optoelectronic devices. Molecular level insight into the interactions between donors and acceptors are crucial for understanding how such interactions can modify the optical properties of the organic optoelectronic materials. In this paper, tris(4-(tert-butyl)phenyl)amine (pTPA) was synthesized as a donor in order to compare with unmodified triphenylamine (TPA) in a donor-acceptor system by having 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. Dimerization of donors and acceptors occurred in solvent when the concentration of solute is high. At 0 K, using a polarizable continuum model, the nitrogen atom of TPA is found to stack on top of the center of triazine of TRZ, whereas such alignment is offset in pTPA and TRZ. We attributed such alignment in TPA-TRZ as the result of attractive interactions between partial localization of 2p z electrons at the nitrogen atom of TPA and the π deficiency of triazine in TPA-TRZ. By taking into account random motions of the solvent effect at 300 K in quantum molecular dynamics and classical molecular dynamics simulations to interpret the marked difference in emission spectra between TPA-TRZ and pTPA-TRZ, it was revealed that the attractive interaction between pTPA and TRZ in toluene is weaker than TPA and TRZ. Because of the weaker attractive interaction between pTPA and TRZ in toluene, the dimers adopted numerous ground state conformations resulting in broad emission bands superimposed with multiple small Gaussian peaks. This is in contrast to TPA-TRZ which has only one dominant dimer conformation. This study demonstrates that the strength of intermolecular interactions between donors and acceptors should be taken into consideration in designing supramolecular structures.

show abstract

“…There are several reported methods to obtain these values experimentally. [22] For instance, these values can be obtained from the integration of the emission decay corresponding to the prompt and delayed emission, respectively. [23] Also, there is the rough method of using the experimentally determined PLQY under aerated conditions as a surrogate for ; however, the triplet state may not be completely quenched by O2 under aerated conditions, and it is not the case that oxygen is benign to react with the S1 state of TADF materials as its presence has been shown to increase the nonradiative decay path from the S1…”

Section: Derivation Of Rate Equations Using Steady-state Approximationmentioning

confidence: 99%

Exact Solution of Kinetic Analysis for Thermally Activated Delayed Fluorescence Materials

Tsuchiya¹,

Diesing²,

Bencheikh³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

The photophysical analysis of thermally activated delayed fluorescence (TADF) materials has become instrumental to providing insight into their stability and performance, which is not only relevant for organic light-emitting diodes (OLED), but also for other applications such as sensing, imaging and photocatalysis. Thus, a deeper understanding of the photophysics underpinning the TADF mechanism is required to push materials design further. Previously reported analyses in the literature of the kinetics of the various processes occurring in a TADF material rely on several a priori assumptions to estimate the rate constants for forward and reverse intersystem crossing (ISC and RISC, respectively). In this report, we demonstrate a method to determine these rate constants using a three-state model together with a steady-state approximation and, importantly, no additional assumptions. Further, we derive the exact rate equations, greatly facilitating a comparison of the TADF properties of structurally diverse emitters and providing a comprehensive understanding of the photophysics of these systems.

show abstract

“…There are several reported methods to obtain these values experimentally. [22] For instance, these values can be obtained from the integration of the emission decay corresponding to the prompt and delayed emission, respectively. [23] Also, there is the rough method of using the experimentally determined PLQY under aerated conditions as a surrogate for ; however, the triplet state may not be completely quenched by O2 under aerated conditions, and it is not the case that oxygen is benign to react with the S1 state of TADF materials as its presence has been shown to increase the nonradiative decay path from the S1…”

Section: Derivation Of Rate Equations Using Steady-state Approximationmentioning

confidence: 99%

Exact Solution of Kinetic Analysis for Thermally Activated Delayed Fluorescence Materials

Tsuchiya¹,

Diesing²,

Bencheikh³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

The photophysical analysis of thermally activated delayed fluorescence (TADF) materials has become instrumental to providing insight into their stability and performance, which is not only relevant for organic light-emitting diodes (OLED), but also for other applications such as sensing, imaging and photocatalysis. Thus, a deeper understanding of the photophysics underpinning the TADF mechanism is required to push materials design further. Previously reported analyses in the literature of the kinetics of the various processes occurring in a TADF material rely on several a priori assumptions to estimate the rate constants for forward and reverse intersystem crossing (ISC and RISC, respectively). In this report, we demonstrate a method to determine these rate constants using a three-state model together with a steady-state approximation and, importantly, no additional assumptions. Further, we derive the exact rate equations, greatly facilitating a comparison of the TADF properties of structurally diverse emitters and providing a comprehensive understanding of the photophysics of these systems.

show abstract

Minimization of solid-state conformational disorder in donor–acceptor TADF compounds

Abstract: Thermally activated delayed fluorescence (TADF) compounds with a flexible donor–acceptor structure suffer from conformational disorder in solid-state, which deteriorates their emission properties as well as OLED performance.

Cited by 52 publications

References 41 publications

Effect of Bulky Functional Groups on Donor and Acceptor Interactions and their Photoluminescence Properties

Effect of Bulky Functional Groups on Donor and Acceptor Interactions and their Photoluminescence Properties

Exact Solution of Kinetic Analysis for Thermally Activated Delayed Fluorescence Materials

Exact Solution of Kinetic Analysis for Thermally Activated Delayed Fluorescence Materials

Contact Info

Product

Resources

About