Highly efficient (EQE &gt; 27%) Yellow OLEDs using spiro[fluorene-9,9′-phenanthren-10′-one]-carbazole-based donor–acceptor–donor host materials

Lin, Yu Hsuan; Lin, Wei-Yang; Huang, Yi‐Sheng; Wu, Chen-Hsun; Gnanasekaran, Premkumar; Chang, Yang‐Ming; Teng, Sheng-Wei; Lu, Chin‐Wei; Chang, Chih-Hao; Chang, Yuan Jay

doi:10.1039/d2tc05296b

Cited by 9 publications

(3 citation statements)

References 39 publications

(47 reference statements)

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“…In contrast to symmetric host systems, 46–49 asymmetric structures 50–54 with bipolar characteristics were competent to be high-performance TADF hosts with balanced carrier injecting/transporting abilities, in addition to amplified steric hindrance for suppressing triplet quenching effects. In our previous works, 55–58 spirocyclic cores and steric phosphine oxide (PO) groups were integrated to develop a series of efficient host matrixes for blue and white TADF diodes.…”

Section: Introductionmentioning

confidence: 94%

Phosphorylation amplified asymmetry of spiro[acridine-9,9′-xanthene] hosts for efficient blue and white thermal activated delay fluorescent diodes

Zhu,

Li,

Man

et al. 2023

J. Mater. Chem. C

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Section: Introductionmentioning

confidence: 94%

Phosphorylation amplified asymmetry of spiro[acridine-9,9′-xanthene] hosts for efficient blue and white thermal activated delay fluorescent diodes

Zhu,

Li,

Man

et al. 2023

J. Mater. Chem. C

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“…Different strategies were developed to redshift the absorption of the sulfonium salts, and an efficient strategy was proposed by using fluorene as a π-conjugated spacer [288]. Fluorene is an excellent electron-donating group that was notably used for the design of chromophores for solar cells [289][290][291][292][293][294][295][296][297][298][299], light emitters for OLEDs [300][301][302][303][304][305][306] and charge transport materials for OFETs [307][308][309][310][311][312][313][314][315] and as fluorescent probes [316][317][318][319][320][321][322][323]. The fluorene scaffold was notably used by Yagci and coworkers to design thioxanthone exhibiting a high molar extinction coefficient and a redshifted absorption compared with PI-PAG [324].…”

Section: Fluorene-based Sulfonium Saltsmentioning

confidence: 99%

Recent Advances in Monocomponent Visible Light Photoinitiating Systems Based on Sulfonium Salts

Dumur

2023

Polymers

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During the last decades, multicomponent photoinitiating systems have been the focus of intense research efforts, especially for the design of visible light photoinitiating systems. Although highly reactive three-component and even four-component photoinitiating systems have been designed, the complexity to elaborate such mixtures has incited researchers to design monocomponent Type II photoinitiators. Using this approach, the photosensitizer and the radical/cation generator can be combined within a unique molecule, greatly simplifying the elaboration of the photocurable resins. In this field, sulfonium salts are remarkable photoinitiators but these structures lack absorption in the visible range. Over the years, various structural modifications have been carried out in order to redshift their absorptions in the visible region. In this work, an overview of the different sulfonium salts activable under visible light and reported to date is proposed.

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“…On the other hand, reducing the negative impact of intermediate CGLs with uneven charge generation efficiency in tandem devices consisting of three or more EUs results in carrier imbalance in each EU. Exciplex or co-host systems generated by the mixture of specific electron donor (D) molecules and electron acceptor (A) molecules are potential EML designs to maintain the carrier balance and EL efficiency in each EU. ,, D/A molecules used in the exciplex host system are usually HTM/ETM with high carrier mobility, enabling researchers to arbitrarily adjust the blending D/A ratio to achieve carrier balance and also ensure that the exciton formation zone is effectively allocated in the EML. , Furthermore, this mixed host system could transport holes and electrons simultaneously and thus expand the recombination zone in the EML, mitigating the exciton quenching. − Last but not least, the light extraction structure introduced in TOLEDs could substantially improve the light outcoupling of the device and significantly prolong device lifetime compared to conventional devices operating at the same luminance level, enabling OLEDs to meet the stringent requirements for lighting or phototherapy applications. According to our previous studies, an embedded NP-based diffuser structure should have great potential to improve the outcoupling efficiency of the tandem device and reduce the directional emission due to the microcavity effect. − …”

Section: Introductionmentioning

confidence: 99%

Enhancing Tandem Organic Light-Emitting Diode Performance with Multiple Electroluminescent Units

et al. 2023

Self Cite

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Tandem organic light-emitting diodes (TOLEDs) which stack multiple electroluminescent units (EUs) via a charge-generation layer (CGL) are advanced device designs that improve the electroluminescent (EL) performance and operating lifetime. However, each CGL used in a device with multiple EUs is affected by electrodes and the other CGLs, resulting in a suboptimal ability to generate carriers and thus decreasing device efficiency and luminance values. Herein, four specific designs, including an effective CGL structure, an exciplex host for the emitting layer (EML), simplified device architectures, and nanoparticle-based diffusers, are proposed to realize highly efficient TOLEDs, aiming to sustain or even surpass the external quantum efficiency linearity with the number of stacked EUs. Aside from the heterojunction structure of the CGL, the n-type electron injection layer also plays a critical role in efficient charge generation. In addition, the exciplex host used in the EML could improve the carrier balance and reduce the operating voltages. The EL efficiency of the three-stacked tandem device reaches 78.7% (303.5 cd A–1), about 2.5 times that of the conventional device, which fails to meet the expected value. When a nanoparticle-based diffuser layer was inserted between the substrate and the anode of the three-stacked TOLEDs, the EL efficiency of the device rose to 123.9% (456.9 cd A–1), about 3.9-fold that of the conventional device. Furthermore, an ultra-high maximum luminance of 411,531 cd m–2 could be obtained, exceeding that of the conventional device by 5.8 times. Notably, the maximum current efficiency of device T3D reaches record highs compared to the reported green TOLEDs. These results demonstrate the viability of practical design strategies for TOLEDs with multiple EUs for realizing high EL efficiency and luminance values, thus fulfilling the requirements for OLED phototherapy and display applications.

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Highly efficient (EQE > 27%) Yellow OLEDs using spiro[fluorene-9,9′-phenanthren-10′-one]-carbazole-based donor–acceptor–donor host materials

Abstract: Four bipolar host materials, namely MS-CN, MS-OC, MS-PC, and MS-TPA were designed, synthesized, and their photophysical and electrochemical studies were investigated.

Cited by 9 publications

References 39 publications

Phosphorylation amplified asymmetry of spiro[acridine-9,9′-xanthene] hosts for efficient blue and white thermal activated delay fluorescent diodes

Phosphorylation amplified asymmetry of spiro[acridine-9,9′-xanthene] hosts for efficient blue and white thermal activated delay fluorescent diodes

Recent Advances in Monocomponent Visible Light Photoinitiating Systems Based on Sulfonium Salts

Enhancing Tandem Organic Light-Emitting Diode Performance with Multiple Electroluminescent Units

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