High-Efficiency Red-Fluorescent Organic Light-Emitting Diodes with Excellent Color Purity

Li, Zhiyi; Hu, Xiaoxiao; Liu, Guanhao; Tian, Lei; Gao, Hongjun; Dong, Xiangyu; Gao, Teng; Cao, Man; Lee, Chun‐Sing; Wang, Pengfei; Wang, Ying

doi:10.1021/acs.jpcc.0c10769

Cited by 30 publications

(24 citation statements)

References 40 publications

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“…When TXO-TPA sensitized with DBP fluorescent system exhibited a high energy transfer efficiency up to 90 % along with high PLQY of 66.8 %. [46] With the support of high energy transfer, TXO-TPA based hyperfluorescence device achieved a Chemistry-A European Journal maximum EQE 16.9 %. Recently in 2021, Kwon et al reported hyperfluorescence system using BODIPY type red fluorescent material of 4tBuMB.…”

Section: Orange Red Tadf Emitters In Hyperfluorescence Systemmentioning

confidence: 99%

Molecular Design Strategy for Orange Red Thermally Activated Delayed Fluorescence Emitters in Organic Light‐Emitting Diodes (OLEDs)

Naveen

Prabhu

Braveenth

et al. 2022

Chemistry A European J

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Pure organic molecules based thermally activated delayed fluorescence (TADF) emitters have been successfully developed in recent years for their propitious application in highly efficient organic light emitting diodes (OLEDs). In the case of orange red emitters, the non-radiative process is known to be a serious issue due to its lower lying singlet energy level. However, recent studies indicate that there are tremendous efforts put to develop efficient orange red TADF emitters. In addition, the external quantum efficiency (EQE) of heteroaromatic based orange red TADF OLEDs surpassed 30 %. Such heteroaromatic type emitters showed wide emission spectra; therefore, more attention is being paid to develop highly efficient orange red TADF emitters along with good color purity. Herein, the recent progress of orange red TADF emitters based on molecular structures, such as cyanobenzene, heteroaromatic, naphthalimide, and boronbased acceptors, are reviewed. Further, our insight on these acceptors has been provided by their photophysical studies and device performances. Future perspectives of orange red TADF emitters for real practical applications are discussed.[a] K.

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Section: Orange Red Tadf Emitters In Hyperfluorescence Systemmentioning

confidence: 99%

Molecular Design Strategy for Orange Red Thermally Activated Delayed Fluorescence Emitters in Organic Light‐Emitting Diodes (OLEDs)

Naveen

Prabhu

Braveenth

et al. 2022

Chemistry A European J

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“…Experimentally this can be observed as a superposition of TADFactive and fluorescent emission and absorption wavelength ranges. Importantly, spectrally narrow emissions with efficient External Quantum Emissions (EQE) have been identified mostly for blue and green HF emitters [30][31][32][33][34][35] , while pursuing both parameters at yellow and more bathochromically shifted regions is troublesome as most of the ongoing work in this space provides systems that do not exceed 20% EQE 34,[36][37][38][39][40][41] or provide broad emission bands 42 (Figure 1). Therefore, prerequisite of emission/absorption overlap seems to be insufficient.…”

Section: Introductionmentioning

confidence: 99%

Tandem rigidification and π-extension as a key tool for the development of a narrow linewidth yellow hyperfluorescent OLED system.

Bartkowski

Crocomo

Kochman

et al. 2022

Preprint

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Hyperfluorescence (HF), a relatively new phenomenon utilizing excitons transfer between two luminophores, requires careful pairwise tuning of molecular energy levels and is proposed to be the crucial step toward the development of new, highly effective OLED systems. To date, barely a few HF yellow emitters with desired narrowband emission but moderate external quantum efficiency (EQE <20%) have been reported. This is because a systematic strategy embracing both Förster Resonance Energy Transfer (FRET) and triplet to singlet (TTS) transition as complementary mechanisms for effective excitons transfer has not yet been proposed. Herein, we present a rational approach, which allows to through subtle structural modification, a pair of compounds built from the same donor and acceptor subunits, but with varied communication between these ambipolar fragments, to be obtained. The TADF-active dopant is based on a naphthalimide scaffold linked to the nitrogen of a carbazole moiety, which through the introduction of an additional bond leads not only to π-cloud enlargement but also rigidifies and inhibits rotation of the donor. This structural change prevents TADF, and allows to guide bandgaps and excited states energies to simultaneously pursue FRET and TTS process. New OLED devices utilizing the presented emitters show excellent external quantum efficiency (up to 27%) and narrow full width at half maximum (40nm), which is a consequence of very good alignment of energy levels. The presented design principles prove that only a minor structural modification is needed to obtain commercially applicable dyes for HF OLED devices.

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“…Organic semiconductors are widely used in modern optoelectronic devices, such as organic light-emitting diodes (OLEDs), quantum-dot light-emitting diodes (QLEDs), organic solar cells (OSCs), perovskite solar cells (PSCs), and field-effect transistors (OFETs). − All of these optoelectronic devices are based on charge transfer, which requires rigorous movement of charges. The optoelectronic characteristics of these materials vary from those of inorganic crystalline semiconductors in many ways.…”

Section: Introductionmentioning

confidence: 99%

Study on Electron Transport Characterization in TPBi Thin Films and OLED Application

Wang

Jiang

et al. 2021

J. Phys. Chem. C

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We characterize the electron transport properties of 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) thin films with various thicknesses (150–260 nm) via admittance spectroscopy (AS). The electron mobilities of TPBi films with different thicknesses are calculated in the range from (5.6 × 10–8) to (2.1 × 10–5) cm2 V–1 s–1, which increase as the applied electric field increases. It is found that the electron mobility of the TPBi thin films is much lower than those of 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB) and 1,3-bis(3,5-dipyrid-3-yl-phenyl)benzene (BmPyPB). We also investigate the performances of red organic light-emitting diodes (OLEDs) based on TPBi, TmPyPB, and BmPyPB as the corresponding electron transport layers (ETLs). The results show that the performance of the TPBi ETL device is obviously inferior to those of the other two devices. By the analysis of the energy-level diagram of the used materials and work mechanisms of the devices, the reasons for their performance differences are examined.

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High-Efficiency Red-Fluorescent Organic Light-Emitting Diodes with Excellent Color Purity

Cited by 30 publications

References 40 publications

Molecular Design Strategy for Orange Red Thermally Activated Delayed Fluorescence Emitters in Organic Light‐Emitting Diodes (OLEDs)

Molecular Design Strategy for Orange Red Thermally Activated Delayed Fluorescence Emitters in Organic Light‐Emitting Diodes (OLEDs)

Tandem rigidification and π-extension as a key tool for the development of a narrow linewidth yellow hyperfluorescent OLED system.

Study on Electron Transport Characterization in TPBi Thin Films and OLED Application

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