Assistant dopant system in solution processed phosphorescent OLEDs and its mechanism reveal

Hu, Juntao; Hu, Sheng; Lu, Chaochao; Huang, Yang; Xu, Kai; Wang, Xianghua

doi:10.1016/j.optmat.2017.11.007

Cited by 10 publications

(6 citation statements)

References 27 publications

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“…This result is consistent with the observed slight peak narrowing in the emission spectra of 4CzIPN when going from neat film to blend. [ 35,36 ] It is intriguing that the evolutions of the S 1 and T 1 energy distributions in going from neat film to blend follow a trend opposite to those of the carbazole‐IPN dihedral angles (compare Figure S2, Supporting Information, and Figure 3).…”

Section: Resultsmentioning

confidence: 99%

The Role of Intermolecular Interactions on the Performance of Organic Thermally Activated Delayed Fluorescence (TADF) Materials

Cho

Hong²,

Coropceanu

et al. 2021

Advanced Optical Materials

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In most instances, thermally activated delayed fluorescence (TADF) emitters are incorporated into a suitable host matrix at low doping concentration in order to reduce emission quenching and to improve organic light‐emitting diode (OLED) efficiency. Here, a combination of molecular dynamics simulations and density functional theory calculations is performed for thin films of 1) the neat 4CzIPN TADF emitter and 2) the (guest–host) 4CzIPN:mCBP system, in order to determine how guest–guest and guest–host interactions influence the morphological, electronic, and luminescence properties of the TADF emitters. The red‐shift in emission recently observed experimentally upon increasing the concentration in TADF emitters is attributed to the formation of guest–guest, i.e., dimer, intermolecular charge‐transfer states. It is found that the radiative and reverse intersystem crossing rates associated with these dimer states are similar to those of monomers. Thus, the contributions from both the dimer and monomer states need to be considered to describe TADF within the emissive layer. The exciton diffusion processes are also characterized; singlet excitons are calculated to be the main contributors to the diffusion length, in contrast to recently proposed models.

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Section: Resultsmentioning

confidence: 99%

The Role of Intermolecular Interactions on the Performance of Organic Thermally Activated Delayed Fluorescence (TADF) Materials

Cho

Hong²,

Coropceanu

et al. 2021

Advanced Optical Materials

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“… 42 ] However, because each proportion depending on the doping ratio is different, the dominant point of each mechanism can be different. [ 43,44 ] In our WOLED, by finding the dominant point of the ET, it was possible to achieve a reliable color index as well as a high color index that is closest to daylight. Figure 2c,d,e show color spectra data according to the mixing ratios of the RGB solutions and applied driving voltages in each WOLEDs.…”

Section: Discussion and Resultsmentioning

confidence: 99%

High‐Performance and Reliable White Organic Light‐Emitting Fibers for Truly Wearable Textile Displays

et al. 2022

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Light‐emitting fibers have been intensively developed for the realization of textile displays and various lighting applications, as promising free‐form electronics with outstanding interconnectivity. These advances in the fiber displays have been made possible by the successful implementation of the core technologies of conventional displays, including high optoelectronic performance and essential elements, in the fiber form‐factor. However, although white organic light‐emitting diodes (WOLEDs), as a fundamental core technology of displays, are essential for realizing full‐color displays and solid‐state lighting, fiber‐based WOLEDs are still challenging due to structural issues and the lack of approaches to implementing WOLEDs on fiber. Herein, the first fiber WOLED is reported, exhibiting high optoelectronic performance and a reliable color index, comparable to those of conventional planar WOLEDs. As key features, it is found that WOLEDs can be successfully introduced on a cylindrical fiber using a dip‐coatable single white‐emission layer based on simulation and optimization of the white spectra. Furthermore, to ensure durability from usage, the fiber WOLED is encapsulated by an Al2O3/elastomer bilayer, showing stable operation under repetitive bending and pressure, and in water. This pioneering work is believed to provide building blocks for realizing complete textile display technologies by complementing the lack of the core technology.

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“…Inspired by those achievements in v-OLEDs, efficient phosphorescent [422], sensitized fluorescent [427] and TADF s-OLEDs [314] have also been fabricated. For instance, Hu's group [428] developed a s-PhOLED by using the state-of-the-art TADF molecule 4CzIPN [27] as assistant host dispersed into a red phosphor doped EML comprising of CBP: bis[2-(4-n-hexylphenyl)quinoline](acetylacetonate)iridium(III) (Hex-Ir(phq)2(acac)) (1.5 wt. %).…”

Section: Efficient S-oleds With Tadf Hostsmentioning

confidence: 99%

“…The proposed ET process in EML, in which the host, assistant TADF dopant and guest are CBP, 4CzIPN and Hex-Ir(phq)2(acac), respectively (from Ref. [428]). [422].…”

Section: Efficient S-oleds With Tadf Hostsmentioning

confidence: 99%

Towards high-power-efficiency solution-processed OLEDs: Material and device perspectives

Wang

Zhang

et al. 2020

Materials Science and Engineering: R: Reports

216

142

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