Suppression of benzophenone-induced triplet quenching for enhanced TADF performance

Kreiza, Gediminas; Banevičius, Dovydas; Jovaišaitė, Justina; Maleckaitė, Karolina; Gudeika, Dalius; Volyniuk, Dmytro; Gražulevičius, Juozas V.; Juršėnas, Saulius; Kazlauskas, Karolis

doi:10.1039/c9tc02408e

Cited by 56 publications

(37 citation statements)

References 53 publications

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“…The improved F FL values of the compounds in mCP were accompanied by notably enhanced contributions of the DF components (Table 1 and Table S3, ESI †), implying reduced non-radiative decay from the triplet states most likely due to suppressed vibronic coupling to the ground state. 21 The vibronically-modulated prompt FL and phosphorescence spectra of tCz-ND in mCP obtained at 10 K again confirmed the origin of the emissive states to be of a more localized (and less CT) nature. Conversely, the analogous spectra of MetCz-ND with redshifted structureless emission clearly indicated the CT-like origin of the states (Fig.…”

Section: Photophysical Propertiesmentioning

confidence: 59%

Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs

et al. 2020

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Section: Photophysical Propertiesmentioning

confidence: 59%

Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs

et al. 2020

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“…Prompt fluorescence decay transients of 10 wt % DPEPO films of compounds PXZ-PYR , PXZ-muPYR , PXZ-mdPYR , and PXZ-2mPYR in the −O 2 surrounding (see Figure 4 b) were similar to toluene solutions; however, the TADF decay was strongly multiexponential for compounds PXZ-muPYR , PXZ-mdPYR , and PXZ-2mPYR due to the presence of conformational disorder (see Figure S31 in the Supporting Information for time-resolved spectra, showing temporal shifts of the emission peak). 37 , 52 , 56 − 61 Although no exact TADF lifetime and decay rates could be estimated, still the slowest TADF decay could be attributed for PXZ-2mPYR . On the contrary, an approximate three-exponential fit of fluorescence decay transient was successfully applied for PXZ-muPYR with the most rapid rISC in toluene, 37 though the latest DF decay tail (from about 10 –5 to about 10 –4 s) still was impossible to fit.…”

Section: Resultsmentioning

confidence: 99%

Achieving Submicrosecond Thermally Activated Delayed Fluorescence Lifetime and Highly Efficient Electroluminescence by Fine-Tuning of the Phenoxazine–Pyrimidine Structure

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Skaisgiris

Dodonova

et al. 2020

ACS Appl. Mater. Interfaces

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Thermally activated delayed fluorescence (TADF) materials, combining high fluorescence quantum efficiency and short delayed emission lifetime, are highly desirable for application in organic light-emitting diodes (OLEDs) with negligible external quantum efficiency (EQE) roll-off. Here, we present the pathway for shortening the TADF lifetime of highly emissive 4,6-bis[4-(10-phenoxazinyl)phenyl]pyrimidine derivatives. Tiny manipulation of the molecular structure with methyl groups was applied to tune the singlet–triplet energy-level scheme and the corresponding coupling strengths, enabling the boost of the reverse intersystem crossing (rISC) rate (from 0.7 to 6.5) × 10 6 s –1 and shorten the TADF lifetime down to only 800 ns in toluene solutions. An almost identical TADF lifetime of roughly 860 ns was attained also in solid films for the compound with the most rapid TADF decay in toluene despite the presence of inevitable conformational disorder. Concomitantly, the boost of fluorescence quantum efficiency to near unity was achieved in solid films due to the weakened nonradiative decay. Exceptional EQE peak values of 26.3–29.1% together with adjustable emission wavelength in the range of 502–536 nm were achieved in TADF OLEDs. Reduction of EQE roll-off was demonstrated by lowering the TADF lifetime.

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“…Both k r and k rISC were showcased as both strongly depending on the emission yield, and both rates are used for the estimation of other major fluorescence parameters. 5 , 8 …”

Section: Resultsmentioning

confidence: 99%

“…k rISC was calculated according to the models used in the initial reports. k rISC of 4CzPN was calculated according to Kreiza et al 8 …”

Section: Resultsmentioning

confidence: 99%

TADF Parameters in the Solid State: An Easy Way to Draw Wrong Conclusions

et al. 2021

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The successful development of thermally activated delayed fluorescence (TADF) OLEDs relies on advances in molecular design. To guide the molecular design toward compounds with preferable properties, special care should be taken while estimating the parameters of prompt and delayed fluorescence. Mistakes made in the initial steps of analysis may lead to completely misleading conclusions. Here we show that inaccuracies usually are introduced in the very first steps while estimating the solid-state prompt and delayed fluorescence quantum yields, resulting in an overestimation of prompt fluorescence (PF) parameters and a subsequent underestimation of the delayed emission (DF) yield and rates. As a solution to the problem, a working example of a more sophisticated analysis is provided, stressing the importance of in-depth research of emission properties in both oxygen-saturated and oxygen-free surroundings.

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Suppression of benzophenone-induced triplet quenching for enhanced TADF performance

Abstract: An effective way to suppress non-radiative triplet quenching and enhance rISC up to 100% in benzophenone-derived blue TADF emitters is proposed.

Cited by 56 publications

References 53 publications

Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs

Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs

Achieving Submicrosecond Thermally Activated Delayed Fluorescence Lifetime and Highly Efficient Electroluminescence by Fine-Tuning of the Phenoxazine–Pyrimidine Structure

TADF Parameters in the Solid State: An Easy Way to Draw Wrong Conclusions

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