Solution‐Processable Thermally Activated Delayed Fluorescence White OLEDs Based on Dual‐Emission Polymers with Tunable Emission Colors and Aggregation‐Enhanced Emission Properties

Li, Chensen; Nobuyasu, Roberto S.; Wang, Yukun; Dias, Fernando B.; Ren, Zhongjie; Yan, Shouke

doi:10.1002/adom.201700435

Cited by 106 publications

(69 citation statements)

References 59 publications

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“…Vinyl Polymers: As for the nonconjugated side chain TADF polymers, the TADF vinyl polymers based on nonconjugated all‐carbon backbone as derived from vinyl monomers, play a dominant role. Dias et al . linked the phenothiazine‐dibenzothiophene‐ S,S ‐dioxide ( PTZ‐DBTO2 ) TADF moiety as side group through a vinyl monomer ( V‐PTZ‐DBTO2 ) to prepare a series of TADF polymers.…”

Section: Tadf Polymersmentioning

confidence: 99%

“…In a further study, V‐PTZ‐DBTO2 was selected to prepare copolymers PPzPT‐1 to 3 (Figure ) at different input ratios (50:50, 80:20, and 90:10) . In these polymers, PTZ‐DBTO2 can endow the polymer with TADF and aggregation‐enhanced emission (AEE) properties, while the dibenzothiophene ( DBT) unit of the vinyl comonomer has a high triplet energy (3.04 eV) and good hole‐transporting property, which can also disperse the PTZ‐DBTO2 component and thus can regulate the aggregation and quenching.…”

Section: Tadf Polymersmentioning

confidence: 99%

“…Finally, OLEDs with the structure of (ITO)/PEDOT:PSS (40 nm)/polymer:TCTA:TAPC (10:65:25 wt%) (45 nm)/TmPyPB (50 nm)/LiF (0.8 nm)/Al (80 nm) were fabricated. The devices based on PPzPT‐1 and PPzPT‐2 show yellow emission, with a very low maximum EQE of 1.1% and 4.5%, while PPzPT‐3 OLEDs show two‐color warm‐white emission with maximum EQE of 10.4% …”

Section: Tadf Polymersmentioning

confidence: 99%

“…In these copolymers, 2‐(10 H ‐phenothiazin‐10‐yl)dibenzothiophene‐S,S‐dioxide ( O ) units give green‐yellow TADF, while hole‐transporting 9‐(4‐vinylphenyl)‐9 H ‐carbazole ( Cz ) units or electron‐transporting diphenyl(4‐vinylphenyl)phosphine oxide act as separating units and hosts. However, in OLED devices, these copolymers provided disappointing performance with an EQE of only 1.2% for PCzPT‐19 and the highest achieved EQE of only 5.2% for POPT‐25 . All these examples indicate that in the copolymer concept, fine‐tuning of the composition is essential, and more research is needed to understand the complex interplay of the TADF and non‐TADF comonomer units.…”

Section: Tadf Polymersmentioning

confidence: 99%

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Thermally Activated Delayed Fluorescent Polymers: Structures, Properties, and Applications in OLED Devices

Wei

Voit

2018

Macromol. Rapid Commun.

124

100

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several organic layers like hole injection layer, hole-and electron transport layer, and most importantly, the emissive layers (EML), inserted between the electrodes (Figure 1). Under external voltage, opposite charge carriers of holes and electrons are injected from anode and cathode and finally recombined to produce photons within the EML. [10][11][12] Emitters can largely determine not only the performance but also the processing methods of devices, and therefore they are the key material among all the components of the OLEDs. During the past three decades, the emitter materials have seen a rapid progress, from traditional fluorescent, phosphorescent, and triplet-triplet annihilation (TTA) materials into the era of thermally activated delayed fluorescent (TADF) materials, and from small molecules to polymers. [13] According to spin statistics, singlet and triplet excitons are formed within the EML at the ratio of 1:3, when OLED devices are working under electrical excitation; however, the organic emitters have different capabilities to utilize the exciton to induce photons which results in different efficiencies of OLED devices. The electricity-photon conversion efficiency of OLED can be evaluated by the quantum efficiency (QE), referring to the numeral ratio of photons to the injected electronhole pairs. [14,15] QE can be further subdivided into internal quantum efficiency (IQE) and external quantum efficiency (EQE). The IQE, defined as photon generation within the EML, is directly determined by the emitters, [16] while EQE refers to the numerical ratio of total photons emitting out of the device to the charge pairs injected. Since the photons are generated within and emitted out from the EML, the chemical structure of the emitter and the resulting properties can deeply influence the device efficiency. The traditional fluorescent emitters can only take advantages of singlet excitons for luminescence, with maximal IQE of roughly 25%. Given that out-coupling efficiency is normally 20%, the maximal EQE is only 5%, far below expectation. Phosphorescent OLEDs have the capability to reach 100% IQE, because phosphorescent emitters usually contain heavy atoms like iridium or platinum to harvest both, singlet and triplet excitons for phosphorescence through significant spin-orbit coupling, but the heavy metals usually bring about serious issues of comparable high costs and low long-term stability in OLEDs. [17] TTA fluorescent emitters can only reach a maximum IQE of 62.5% through conversion of two triplet excitons into one singlet exciton, and show mainly blue emission. [18] TADF materials, however, can harvest triplet Organic Light-Emitting Diodes Thermally activated delayed fluorescent (TADF) polymers are promising emitting materials to realize highly efficient, large-scale, and low-cost organic light-emitting diodes (OLEDs) since they exhibit various advantages such as heavy-metal-free structures, 100% theoretical internal quantum efficiency, and ease of large-area fabrication through solution process. At present,...

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Section: Tadf Polymersmentioning

confidence: 99%

Section: Tadf Polymersmentioning

confidence: 99%

Section: Tadf Polymersmentioning

confidence: 99%

Section: Tadf Polymersmentioning

confidence: 99%

See 2 more Smart Citations

Thermally Activated Delayed Fluorescent Polymers: Structures, Properties, and Applications in OLED Devices

Wei

Voit

2018

Macromol. Rapid Commun.

124

100

View full text Add to dashboard Cite

show abstract

“…The solution‐processed EL device based on COPO1 exhibited a high EQE max of 20.1%, but a low EQE of 5.3% at 100 cd m −2 . To address this issue, an aggregation‐enhanced emission (AEE) active building block, dibenzothiophene (DBT), was used to replace styrene unit for copolymerization to afford PDTPTDSO x . Introducing DBT as the polymerization partner not only endowed the polymer with AEE properties, but also offered the host with high triplet energy and good hole‐transporting ability.…”

Section: Tadf Polymersmentioning

confidence: 99%

Design Strategy for Solution‐Processable Thermally Activated Delayed Fluorescence Emitters and Their Applications in Organic Light‐Emitting Diodes

Zou

Gong

Xie

et al. 2018

Advanced Optical Materials

212

115

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Organic light-emitting diodes (OLEDs) with fascinating features, such as high image quality, large viewing angle, thin, and lightweight, and their compatibility with rollable, wearable, and stretchable technology, have gradually entered into our daily life as the most promising next-generation displays. As to the advancements of OLED technology, there is ongoing demand on developing highly efficient emitting materials with color variability, which plays a crucial role in governing optoelectronic properties of OLEDs. Following the first generation of traditional fluorescent emitters and the second generation of heavy-metal phosphorescent emitters, [1] thermally activated delayed fluorescence (TADF) materials have emerged in the past few years and have been regarded as the most promising third generation emitters. [2] Aside from their triplet exciton Solution-processable thermally activated delayed fluorescence (TADF) emitters have received tremendous attentions in recent years due to their intrinsic merits of theoretical 100% exciton harvesting capability and excellent compatibility to low-cost and easily scalable solution processes. Herein, a comprehensive review of solution-processable TADF emitters is presented, including small molecules, dendrimers, and polymers. Their molecular design, optoelectronic properties, and device performances are summarized, and specific emphasis is placed on the structure-property relationships of these emitters. This review not only offers a guideline for designing highly efficient TADF emitters compatible with solution-processed organic lightemitting diodes, but also paves further directions for the development of solution-processable TADF emitters.

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Efficient Bipolar Blue AIEgens for High‐Performance Nondoped Blue OLEDs and Hybrid White OLEDs

Chen

Liu

Zeng

et al. 2018

Adv Funct Materials

145

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Blue organic luminescent materials play a crucial role in full-color display and white lighting but efficient ones meeting commercial demands are very rare. Herein, the design and synthesis of tailor-made bipolar blue luminogens with an anthracene core and various functional groups are reported. The thermal stabilities, photophysical properties, electronic structures, electrochemical behaviors, carrier transport abilities, and electroluminescence performances are systematically investigated. The luminogen TPE-TAPBI containing a tetraphenylethene moiety shows aggregation-induced emission, while another luminogen TriPE-TAPBI bearing a triphenylethene unit exhibits light aggregationcaused quenching. In comparison with TriPE-TAPBI, TPE-TAPBI has stronger blue emission in neat film and functions more efficiently in nondoped organic light-emitting diodes (OLEDs). High maxima current, power, and external quantum efficiencies of 7.21 cd A −1 , 6.78 lm W −1 , and 5.73%, respectively, are attained by the nondoped blue OLED of TPE-TAPBI (CIE x,y = 0.15, 0.16). Moreover, efficient two-color hybrid warm white OLEDs (CIE x,y = 0.457, 0.470) are achieved using TPE-TAPBI neat film as the blue-emitting component, which provide total current, power, external quantum efficiencies of up to 70.5 lm W −1 , 76.0 cd A −1 , and 28% at 1000 cd m −2 , respectively. These blue and white OLEDs are among the most efficient devices with similar colors in the literature.

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Solution‐Processable Thermally Activated Delayed Fluorescence White OLEDs Based on Dual‐Emission Polymers with Tunable Emission Colors and Aggregation‐Enhanced Emission Properties

Cited by 106 publications

References 59 publications

Thermally Activated Delayed Fluorescent Polymers: Structures, Properties, and Applications in OLED Devices

Thermally Activated Delayed Fluorescent Polymers: Structures, Properties, and Applications in OLED Devices

Design Strategy for Solution‐Processable Thermally Activated Delayed Fluorescence Emitters and Their Applications in Organic Light‐Emitting Diodes

Efficient Bipolar Blue AIEgens for High‐Performance Nondoped Blue OLEDs and Hybrid White OLEDs

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