High Performance Thermally Activated Delayed Fluorescence Sensitized Organic Light‐Emitting Diodes

Cai, Ming; Zhang, Dongdong

doi:10.1002/tcr.201800148

Cited by 57 publications

(37 citation statements)

References 92 publications

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“…[80][81][82] Additionally, simulations have been used to investigate host materials for efficient charge transport within blue phosphorescent emitters, 83 providing a link between the electronic structure and molecular packing, to the rational design of effective host materials with high charge carrier mobilities. Blue TADF emitters [39][40][41][42][43][44] and combinations of TADF with conventional fluorescent 84,85 or phosphorescent emitters 84,86 have also been investigated. This includes the impact of FIG.…”

Section: Hole Transport Layer (Htl)mentioning

confidence: 99%

Computer aided design of stable and efficient OLEDs

Paterson

May

Andrienko

2020

Journal of Applied Physics

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Organic light emitting diodes (OLEDs) offer a unique alternative to traditional display technologies. Tailored device architecture can offer properties such as flexibility and transparency, presenting unparalleled application possibilities. Commercial advancement of OLEDs is highly anticipated, and continued research is vital for improving device efficiency and lifetime. The performance of an OLED relies on an intricate balance between stability, efficiency, operational driving voltage, and color coordinates, with the aim of optimizing these parameters by employing an appropriate material design. Multiscale simulation techniques can aid with the rational design of these materials, in order to overcome existing shortcomings. For example, extensive research has focused on the emissive layer and the obstacles surrounding blue OLEDs, in particular, the trade-off between stability and efficiency, while preserving blue emission. More generally, due to the vast number of contending organic materials and with experimental pre-screening being notoriously time-consuming, a complementary in silico approach can be considerably beneficial. The ultimate goal of simulations is the prediction of device properties from chemical composition, prior to synthesis. However, various challenges must be overcome to bring this to a realization, some of which are discussed in this Perspective. Computer aided design is becoming an essential component for future OLED developments, and with the field shifting toward machine learning based approaches, in silico pre-screening is the future of material design.

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Section: Hole Transport Layer (Htl)mentioning

confidence: 99%

Computer aided design of stable and efficient OLEDs

Paterson

May

Andrienko

2020

Journal of Applied Physics

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“…TADF materials enable internal quantum efficiency of OLED to reach 100% by utilizing both singlet and triplet excitons without invoking noble metals. However, most reported TADF materials suffer from serious efficiency roll-off and poor color purity due to exciton annihilation and broad emission band, respectively [2]. Thermally Activated Sensitized Fluorescence (TASF) technology was proposed to alleviate some of these problems [3], in which a highly luminescent fluorescent emitter was doped into the TADF emissive layer.…”

Section: Introductionmentioning

confidence: 99%

45.1: High‐Performance Deep Blue OLEDs with EQE up to 31%

Li¹,

Duan

et al. 2021

Symp Digest of Tech Papers

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The low efficiency of blue devices has been a bottleneck problem for OLED panel manufacturers for a long time. In recent years, TASF‐OLED has attracted great attention because of the high external quantum efficiency and color purity, which makes it a promising technology for high efficiency deep blue OLEDs. In this paper, we present our latest development of TADF material for deep blue TASF‐OLEDs with an emission peak at 460 nm and a high external quantum efficiency up to 31 %.

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“…When TADF emitters serve as hosts, their triplet excitons are considered to be up‐converted to the singlet ones via fast RISC processes, and then transferred to the guest emitters through Förster energy transfer. [ 18 ] Indeed, in such a triplet‐involved process, the TTA occurred between two host molecules is not negligible. [ 8 ] In other words, one important principle in host engineering is reducing the intermolecular interactions, which is similar to developing an efficient emitter.…”

Section: Introductionmentioning

confidence: 99%

A Multifunctional Bipolar Luminogen with Delayed Fluorescence for High‐Performance Monochromatic and Color‐Stable Warm‐White OLEDs

Zeng

Guo

Líu

et al. 2020

Adv Funct Materials

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(1 of 11)Increasing exciton utilization and reducing exciton annihilation are crucial to achieve high performance of organic light-emitting diodes (OLEDs), which greatly depend on molecular engineering of emitters and hosts. A novel luminogen (SBF-BP-DMAC) is synthesized and characterized. Its crystal and electronic structures, thermal stability, electrochemical behavior, carrier transport, photoluminescence, and electroluminescence are investigated. SBF-BP-DMAC exhibits enhanced photoluminescence and promotes delayed fluorescence in solid state and bipolar carrier transport ability, and thus holds multifunctionality of emitter and host for OLEDs. Using SBF-BP-DMAC as an emitter, the nondoped OLEDs exhibit maximum electroluminescence (EL) efficiencies of 67.2 cd A −1 , 65.9 lm W −1 , and 20.1%, and the doped OLEDs provide maximum EL efficiencies of 79.1 cd A −1 , 70.7 lm W −1 , and 24.5%. A representative orange phosphor, Ir(tptpy) 2 acac, is doped into SBF-BP-DMAC for OLED fabrication, giving rise to superior EL efficiencies of 88.0 cd A −1 , 108.0 lm W −1 , and 26.8% for orange phosphorescent OLEDs, and forwardviewing EL efficiencies of 69.3 cd A −1 , 45.8 lm W −1 , and 21.0% for two-color hybrid warm-white OLEDs. All of these OLEDs can retain high EL efficiencies at high luminance, with very small efficiency roll-offs. The outstanding EL performance demonstrates the great potentials of SBF-BP-DMAC in practical display and lighting devices.luminous efficiencies and efficient exciton utilization approaching 100%. [2] However, commercial phosphors depend on rare metal elements such as iridium and platinum, and thus are usually expensive. What is more, high doping concentrations (5-20 wt%) of phosphors were recently reported to optimize the device performance, leading to a high manufacturing cost. [3] As promising alternatives, Adachi and co-workers developed purely organic luminescent materials with thermally activated delayed fluorescence (TADF), which can fully utilize the electrogenerated excitons in OLEDs and thus afford excellent external quantum efficiencies (ƞ ext ) of >20% via reverse intersystem crossing (RISC) process based on small singlet-triplet energy gaps (ΔE ST ≤ 0.3 eV) of the molecules. [4] However, on account of the long triplet lifetimes, most phosphors and TADF emitters suffer from negative nonradiative processes in OLEDs, such as aggregation and concentration caused quenching, [5] triplet-triplet annihilation (TTA), [6] singlet-triplet annihilation (STA), [7] and so on, [8] which greatly limits their practical applications. To address the issue, robust luminogens that can alleviate emission quenching and exciton annihilation are extremely desired. According to the previous works, reducing the intermolecular interactions (e.g., π-π interactions) has been evidenced to be an effective strategy to develop efficient luminescent materials with high photoluminescence quantum yields (Φ F s) in neat films and prominent delayed fluorescence. [9] By this way, the emitters are usually insensitive ...

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High Performance Thermally Activated Delayed Fluorescence Sensitized Organic Light‐Emitting Diodes

Cited by 57 publications

References 92 publications

Computer aided design of stable and efficient OLEDs

Computer aided design of stable and efficient OLEDs

45.1: High‐Performance Deep Blue OLEDs with EQE up to 31%

A Multifunctional Bipolar Luminogen with Delayed Fluorescence for High‐Performance Monochromatic and Color‐Stable Warm‐White OLEDs

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