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

Kreiza, Gediminas; Banevičius, Dovydas; Jovaišaitė, Justina; Juršėnas, Saulius; Javorskis, Tomas; Vaitkevičius, Vytenis; Orentas, Edvinas; Kazlauskas, Karolis

doi:10.1039/d0tc01637c

Cited by 37 publications

(16 citation statements)

References 27 publications

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“…As illustrated in Figurer 5f , to our best knowledge, the EQE value of 27.13% for BD‐F based device is at a record high for solution‐processed OLEDs devices. [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ] It also should be noted that the solution‐processable emitters with deep‐blue or near‐infrared color still obviously lag behind others, and thus we need to pay more concentration on promoting their luminescence efficiency through elaborate molecular designing and structural regulation depicted in our work.…”

Section: Resultsmentioning

confidence: 99%

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

et al. 2021

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The state-of-the-art luminescent materials are gained widely by utilizing thermally activated delayed fluorescence (TADF) mechanism. However, the feasible molecular designing strategy of fully exploiting triplet excitons to enhance TADF properties is still in demand. Herein, TADF emitters with multiple conversion channels of triplet excitons are designed by concisely halogenating the electron acceptors containing carbonyl moiety. Compared with the chlorinated and brominated analogues, the fluorinated emitter exhibits distinguishing molecular stacking structures, participating in the formation of trimers through integrating C-H•••F and C═O•••H hydrogen bonds together. It is also demonstrated that the multiple channels can be involved synergistically to accelerate the spin-flip of triplet excitons, and to take charge of the relatively superior reverse intersystem crossing constant rate of 6.20 × 10 5 s -1 , and thus excellent photoluminescence quantum yields over 90% can easily be achieved. Then the solution-processable organic light emitting diode based on fluorinated emitter can achieve a record-high external quantum efficiency value of 27.13% and relatively low efficiency roll-off with remaining 24.74% at 1000 cd m −2 . This result manifests the significance of enhancing photophysical properties through constructing multiple conversion channels of triplets excitons for high-efficiency TADF emitters and provides a guideline for the future study.

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Section: Resultsmentioning

confidence: 99%

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

et al. 2021

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“…Such a high k r for tCN-ND was in line with the rapid PF decay and high oscillator strength of the S 0 → S 1 transition. 27 However, the rapid k r with values exceeding 10 7 , 1 order of magnitude larger than the accurate ones, could be derived if the overestimated Φ PF was used. In this case, k r ranged from 22.7 ( ACRPyr ) to the remarkable 135 × 10 6 s –1 for tCz-ND .…”

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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“…Serving as the smallest alkyl group, the methyl group demonstrates a weak hyperconjugation effect and a steric hindrance effect when linked to an aromatic ring. 4 The methyl group plays an important role in the design of TADF materials where three types of methyl effects can be concluded. 5–10 Type 1: the introduction of methyl groups can effectively improve the luminescence performance of TADF materials.…”

Section: Introductionmentioning

confidence: 99%

Highly efficient blue electroluminescence based on TADF emitters with spiroacridine donors: methyl group effect on photophysical properties

et al. 2022

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

Abstract:
Efficient deep-blue naphthyridine-based TADF emitters featuring narrow-band-emission with low roll-off were designed by using the H-bonding and sterically controlled charge-transfer interactions.

Cited by 37 publications

References 27 publications

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

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

Highly efficient blue electroluminescence based on TADF emitters with spiroacridine donors: methyl group effect on photophysical properties

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

Abstract: Efficient deep-blue naphthyridine-based TADF emitters featuring narrow-band-emission with low roll-off were designed by using the H-bonding and sterically controlled charge-transfer interactions.

Cited by 37 publications

References 27 publications

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

High‐Efficiency Solution‐Processable OLEDs by Employing Thermally Activated Delayed Fluorescence Emitters with Multiple Conversion Channels of Triplet Excitons

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

Highly efficient blue electroluminescence based on TADF emitters with spiroacridine donors: methyl group effect on photophysical properties

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Product

Resources

About

Abstract:
Efficient deep-blue naphthyridine-based TADF emitters featuring narrow-band-emission with low roll-off were designed by using the H-bonding and sterically controlled charge-transfer interactions.