Rigid Polyimides with Thermally Activated Delayed Fluorescence for Polymer Light‐Emitting Diodes with High External Quantum Efficiency up to 21 %

Long, Yubo; Chen, Xiaojie; Wu, Heng; Zhou, Zhuxin; Babu, Seenivasagaperumal Sriram; Wu, Minming; Zhao, Juan; Aldred, Matthew P.; Liu, Siwei; Chen, Xudong; Chi, Zhenguo; Xu, Jiarui; Zhang, Yi

doi:10.1002/anie.202016053

Cited by 39 publications

(32 citation statements)

References 42 publications

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“…Typically, the distinct optical and electronic properties of TADF materials could be attributed to the sufficiently small ΔE ST between the S 1 and T 1 states, enabling an efficient RISC process and a resultant ≈100% internal QE by harvesting both singlet and triplet excitons, which is a crucial theoretical breakthrough in organic electronics. [34][35][36][37][38][39][40] Likewise, such unique optical properties render TADF materials as promising candidates for biomedical applications. Generally, two types of luminescence mechanisms are represented in TADF: the prompt fluorescence (PF) and the delayed fluorescence (DF), which could be triggered by photoexcitation or electroexcitation.…”

Section: Mechanisms Of Tadf Materials For Biomedical Applicationsmentioning

confidence: 99%

Thermally Activated Delayed Fluorescence Material: An Emerging Class of Metal‐Free Luminophores for Biomedical Applications

et al. 2021

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The development of simple, efficient, and biocompatible organic luminescent molecules is of great significance to the clinical transformation of biomaterials. In recent years, purely organic thermally activated delayed fluorescence (TADF) materials with an extremely small single-triplet energy gap (𝚫E ST ) have been considered as the most promising new-generation electroluminescence emitters, which is an enormous breakthrough in organic optoelectronics. By merits of the unique photophysical properties, high structure flexibility, and reduced health risks, such metal-free TADF luminophores have attracted tremendous attention in biomedical fields, including conventional fluorescence imaging, time-resolved imaging and sensing, and photodynamic therapy. However, there is currently no systematic summary of the TADF materials for biomedical applications, which is presented in this review. Besides a brief introduction of the major developments of TADF material, the typical TADF mechanisms and fundamental principles on design strategies of TADF molecules and nanomaterials are subsequently described. Importantly, a specific emphasis is placed on the discussion of TADF materials for various biomedical applications. Finally, the authors make a forecast of the remaining challenges and future developments. This review provides insightful perspectives and clear prospects towards the rapid development of TADF materials in biomedicine, which will be highly valuable to exploit new luminescent materials.

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Section: Mechanisms Of Tadf Materials For Biomedical Applicationsmentioning

confidence: 99%

Thermally Activated Delayed Fluorescence Material: An Emerging Class of Metal‐Free Luminophores for Biomedical Applications

et al. 2021

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“…It is worthy to note that the EQE of pBP-PXZ:CBP exhibits no roll-off when the luminance is less than 200 cd m −2 and just 3% decrease at 500 cd m −2 . The EQE can still be maintained above 19% at 1000 cd m −2 , which represents the best efficiency among TADF polymer-based OLEDs so far under high luminance (Figure 6c) [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] . Those results clearly demonstrate that fine-tuning the polymer backbone structure is significant for improving the overall performances of OLEDs.…”

Section: Electroluminescent Propertiesmentioning

confidence: 99%

Activating Energy Transfer Tunnels by Tuning Local Electronegativity of Conjugated Polymeric Backbone for High‐Efficiency OLEDs with Low Efficiency Roll‐Off

Zhao

Liu

Hua

et al. 2022

Adv Funct Materials

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Thermally activated delayed fluorescence (TADF) conjugated polymers are attractive for display and illumination applications owing to their excellent device performance and convenient device fabrication. However, conjugated polymers frequently encounter insufficient energy transfer from hosts to TADF units, lowering device performance. Herein, a strategy for improving light-emitting performances through adjusting the local electronegativity of the polymeric backbones by inserting electron-withdrawing atoms and activating energy transmission channels is proposed. Meanwhile, strongly electronegative atoms also affect the charge-transfer natures (CT) of TADF polymers and minimize the energy difference between the lowest singlet and triplet states, leading to a rapid reverse intersystem crossing process through the vibronic coupling between 1 CT and 3 CT with extremely close energy levels. The produced TADF polymer, pBP-PXZ, can achieve an external quantum efficiency (EQE) of 23.11%, exhibiting no roll-off when the luminance is less than 200 cd m −2 whereas only a 3% EQE decrease at 500 cd m −2 . The EQE can even maintain above 19% under 1000 cd m −2 , which is the highest efficiency among TADF polymer-based organic light-emitting diodes (OLEDs) under high luminance. The study provides a new perspective for designing highperformance OLEDs materials.

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“…In compared with conjugated polymers, non-conjugated TADF polymers show advantages of facile preparation and wide design freedom, considering a variety of non-conjugated backbones and TADFactive moieties. Recently, we proposed a simple and effective "-TADF-Linker-Host-" design strategy [12] to develop a series of rigid non-conjugated polyimides (PIs)-based TADF polymers (Figure 4), which contain a TADF luminous core structure, PhCzPN host unit, and HPMDA linker unit to improve solubility [12] and inhibit intramolecular charge transfer due to its aliphatic nature. Consequently, the resulted polyimides can well inherit the TADF properties of the TADF unit.…”

Section: Polymer Tadf Emissive Materialsmentioning

confidence: 99%

“…Figure 4. (a) Chemical structures of PI-TADF polymer materials and (b) EQE-luminance curves of these PIpolymers based PLEDs [12]. …”

mentioning

confidence: 99%

28‐2: Invited Paper: The Development of High‐Efficiency Pure Organic Light‐Emitting Materials and High‐Performance White OLEDs

Zhao

Chen

Yang

et al. 2021

Symp Digest of Tech Papers

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The increasing commercial applications of organic light‐emitting diodes (OLEDs) inspire great development of high‐efficiency emissive materials. Among of which, pure organic thermally activated delayed fluorescence (TADF) materials have been considered as the third‐generation OLED emissive materials, and huge attentions are paid to the exploration of molecular design strategies for achieving high efficiency TADF materials. Accordingly, the past years have witnessed a considerable rise in device performance of TADF‐mechanism based OLEDs. In this paper, we would like to provide a brief summary of our research work regarding to TADF materials as well as its applications in OLED including white OLEDs.

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Rigid Polyimides with Thermally Activated Delayed Fluorescence for Polymer Light‐Emitting Diodes with High External Quantum Efficiency up to 21 %

Cited by 39 publications

References 42 publications

Thermally Activated Delayed Fluorescence Material: An Emerging Class of Metal‐Free Luminophores for Biomedical Applications

Thermally Activated Delayed Fluorescence Material: An Emerging Class of Metal‐Free Luminophores for Biomedical Applications

Activating Energy Transfer Tunnels by Tuning Local Electronegativity of Conjugated Polymeric Backbone for High‐Efficiency OLEDs with Low Efficiency Roll‐Off

28‐2: Invited Paper: The Development of High‐Efficiency Pure Organic Light‐Emitting Materials and High‐Performance White OLEDs

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