Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes

Wu, Qiong; Braveenth, Ramanaskanda; Zhang, Heng-Qiang; Bae, Il-Ji; Kim, Miyoung; Chai, Kyu Yun

doi:10.3390/molecules23040843

Cited by 8 publications

(5 citation statements)

References 38 publications

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“…Due to the modest scale of the reactions yielding 3a – 9 , these steps were all conveniently performed under air in sealed, pressurized Teflon-lined vials. This approach is in contrast to other methods, which first involve the assembly of a 1,3,4-oxadiazole core followed by sensitive Pd-catalyzed cross-couplings to append donors. ,− In particular, this oxadiazole synthesis via DCC coupling provided a facile route to mixed donor system 8 , which would have otherwise required multiple Pd-catalyzed reactions. The purity of these materials was verified through the use of 1 H and 13 C{ 1 H} NMR as well as high-resolution mass spectrometry (HRMS).…”

Section: Resultsmentioning

confidence: 99%

Thermally Activated Delayed Fluorescence in 1,3,4-Oxadiazoles with π-Extended Donors

2020

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Here, we describe the synthesis of five 1,3,4oxadiazole-based donor−acceptor materials, using dendritic carbazole-based donors 9′H-9,3′:6′9″-tercarbazole (terCBz) and N3,N3,N6,N6-tetra-p-tolyl-9H-carbazole-3,6-diamine (TTAC). Due to the strongly donating and highly twisted nature of the TTAC donor as well as the spatially separated hole−particle wavefunctions, three of the five compounds exhibited thermally activated delayed fluorescence (TADF) in spite of a relatively large ΔE ST measured through phosphorimetry (0.33−0.37 eV). These materials demonstrated photoluminescence quantum yields as high as 0.89 in toluene, with emission maxima ranging from 474 to 495 nm in the solid state. Additionally, two materials containing only terCBZ donor(s) exhibited deep blue fluorescence, with Commission Internationale de l'ećlairage coordinates of (0.16, 0.05); the weaker nature of the terCBz donor results in a prohibitively large ΔE ST (0.68−0.77 eV). A gap-tuned range-separated hybrid functional (ωB97XD*) was used to rigorously calculate triplet energies, while a systematic analysis of electronic structures and photophysical properties provided further insight into the properties of these materials. These findings ultimately contribute a synthetically facile approach toward highly emissive TADF emitters using a 1,3,4-oxadiazole motif.

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Section: Resultsmentioning

confidence: 99%

Thermally Activated Delayed Fluorescence in 1,3,4-Oxadiazoles with π-Extended Donors

2020

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“…The current density and luminescence of the OLED with a doped polymer anode remained high at high voltages, with a tendency to increase exponentially with an increased voltage, whereas the current density and luminescence of the ITO-based device dropped severely. This is attributed to the quenching caused by exciton annihilation due to the field-induced Joule heating at high current densities, which eventually leads to device lifetime degradation [1,42]. The current density of the OLED with a doped PEDOT:PSS anode was four times higher than that of the OLED with a pristine polymer anode.…”

Section: Resultsmentioning

confidence: 99%

“…Globally conducted experimental studies are oriented around organic light-emitting diodes (OLEDs) due to the interesting opportunities they offer for innovative display and lighting applications [1][2][3][4][5]. The progress towards the development and perfection of highly flexible and stretchable devices enhances the need for a new kind of material possessing the qualities of both highly conductive metal/oxide-based conductors and highly flexible plastics [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Solution-processed colored electrodes for ITO-free blue phosphorescent organic light-emitting diodes

Huseynova

Lim

Gasonoo

et al. 2020

Journal of Information Display

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Reported herein are solution-processed polymer anode electrodes for blue phosphorescent organic light-emitting diodes (PhOLEDs). The highly conductive anodes were made from 10-wt%-methylred-(MR)-doped poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (PH1000) films. The red-colored and uniform polymer films demonstrated electrical conductivity values that significantly increased from 0.25 to 50 S•cm −1 after doping. The more than 200-fold enhancement in conductivity indicates that the doped films have a lower sheet resistance and better hole injection and transport properties than the pristine films. The resultant PhOLEDs based on the doped polymer anodes exhibited stable, broad, and intense blue emission at 468 nm with a 2616 cd•m −2 maximum luminance and a 4 V turn-on voltage. The obtained study results confirmed the effectiveness of the MR dye as a dopant for the significant enhancement of the conductivity and effective hole injection of PEDOT:PSS. Efficient future flexible optoelectronic applications can be built using this highly conductive polymer electrode obtained via a simple, solution-processed, and cost-effective doping approach.

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“…All the materials possessed a high decomposition temperature above 358 • C, with emissions in the PL range of 435-512 nm. For OLED applications, these materials showed a moderate turn-on voltage of around 4.2 V along with a highest EQE of 4.0% when using the material 2PTZ-OXD [202]. properties that emitted blue and red emissions under PL and EL processes when triggered by trifluoroacetic acid (TFA).…”

Section: Oxidiazolementioning

confidence: 99%

Status and Challenges of Blue OLEDs: A Review

Siddiqui,

Kumar,

Tsai

et al. 2023

Nanomaterials

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Organic light-emitting diodes (OLEDs) have outperformed conventional display technologies in smartphones, smartwatches, tablets, and televisions while gradually growing to cover a sizable fraction of the solid-state lighting industry. Blue emission is a crucial chromatic component for realizing high-quality red, green, blue, and yellow (RGBY) and RGB white display technologies and solid-state lighting sources. For consumer products with desirable lifetimes and efficiency, deep blue emissions with much higher power efficiency and operation time are necessary prerequisites. This article reviews over 700 papers covering various factors, namely, the crucial role of blue emission for full-color displays and solid-state lighting, the performance status of blue OLEDs, and the systematic development of fluorescent, phosphorescent, and thermally activated delayed fluorescence blue emitters. In addition, various challenges concerning deep blue efficiency, lifetime, and approaches to realizing deeper blue emission and higher efficacy for blue OLED devices are also described.

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Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes

Cited by 8 publications

References 38 publications

Thermally Activated Delayed Fluorescence in 1,3,4-Oxadiazoles with π-Extended Donors

Thermally Activated Delayed Fluorescence in 1,3,4-Oxadiazoles with π-Extended Donors

Solution-processed colored electrodes for ITO-free blue phosphorescent organic light-emitting diodes

Status and Challenges of Blue OLEDs: A Review

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