High-efficiency hyperfluorescent white light-emitting diodes based on high-concentration-doped TADF sensitizer matrices <i>via</i> spatial and energy gap effects

Xu, Hui; Duan, Chunbo; Xin, Ying; Wang, Zicheng; Zhang, Jing; Han, Chunmiao

doi:10.1039/d1sc05753g

Cited by 17 publications

(19 citation statements)

References 56 publications

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“…Therefore, searching for and using new WOLEs are of particular interest. Recently, hybrid-WOLEDs with blue thermally activated delayed fluorescence (TADF) materials have become an alternative approach that enables the harvesting of both singlet and triplet excitons for light emission. − It is well known that TADF materials can harvest triplet excitons through a reverse ISC (RISC) process from the triplet state to the singlet state due to the low Δ E ST value (typically <0.5 eV). − Based on the TADF mechanism, few TADF-based WOLEDs are reported, where multiple emissive layers are used to modify exciton allocation by spatially separating two or more host-dopant systems of different emission colors. ,,,− Hence, the development of white OLEs (WOLEs) based on TADF that can achieve high efficiency is of great importance. Therefore, if WLE based on multiple TADF emitters with frustrated energy-transfer mechanisms could be achieved, the materials would create new opportunities in WOLEDs due to the light emission of two or three colors in a single emissive layer (EML).…”

Section: Introductionmentioning

confidence: 99%

White Light Emission Achieved by Dual-TADF in a Single Emissive Layer of Multicomponent Emitters

et al. 2023

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White light emission (WLE) from multicomponent organic systems has attracted significant attention in recent years due to easy access of bright blue and yellow/orange, or red emitters. However, realizing WLE from a single emissive layer of multicomponent organic thermally activated delayed fluorescence (TADF) systems is an exasperating task due to uncontrolled Förster energy transfer and Dexter-type triplet–triplet energy transfer (TTET). To address this issue, we demonstrated WLE using blend films (WL1, WL2, and WL3) of blue (CPPN, CQ, and DMOC-DPS) and orange (PTzQ) TADF emitters. WL1 comprises CPPN and PTzQ, while DMOC-DPS and PTzQ were used to construct WL2. Spectroscopic analysis revealed that WL1 and WL2 exhibited dual emission features (quantum yields = 48–54%; Commission Internationale de l’éclairage coordinates: 0.34, 0.31; 0.31, and 0.34) via simultaneous blue- and orange-TADF covering the visible region. The WLE feature is observed due to (i) similar absorption and different Stokes shifted emission color of both the emitters and (ii) the absence of TTET caused by large triplet–triplet gaps (>0.4 eV) between the emitters. In contrast, WLE via fluorescence and TADF was observed in WL3 due to TTET. This finding is expected to provide new insights for designing high-energy-efficient WLE for white organic light-emitting diodes.

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Section: Introductionmentioning

confidence: 99%

White Light Emission Achieved by Dual-TADF in a Single Emissive Layer of Multicomponent Emitters

et al. 2023

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“…Phosphine oxide with strong electron-withdrawing effect is promising as an acceptor for the building of TTA emitters. − Recently, in 2021, Rajamalli et al reported two bipolar green TTA emitters ( 41 and 42 ) by decorating them with an electron-transporting phosphine oxide unit and electron-donating tolylamine and carbazole units (Scheme ). Compounds 41 and 42 exhibited green emission peaks at 520 and 522 nm in toluene, accompanied by the high PLQYs of 63%–68% in toluene and 84%–87% in the neat films, respectively.…”

Section: Triplet–triplet Annihilation Materials and Oledsmentioning

confidence: 99%

Recent Advances in Triplet–Triplet Annihilation-Based Materials and Their Applications in Electroluminescence

Tao

Wong

2023

ACS Materials Lett.

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Efficient and stable blue organic light-emitting devices (OLEDs) represent one of the most important components in future solid-state lighting and full color displays. Although red and green OLEDs have been successfully commercialized, it remains challenging to realize blue OLEDs showing high efficiency and high stability simultaneously, restricting their commercialization. Triplet−triplet annihilation (TTA)-based materials have been emerging as a new category of electroluminescent or host materials with promising potential for highly efficient and stable blue devices due to their appealing photophysical properties (e.g., ability to generate emissive singlet excited states through TTA process, high photoluminescence quantum yield, ease of molecular design, etc.). Recently, research on TTA-based materials toward high-performance blue OLEDs has received an increasing attention. In this review, recent research advances on the molecular design strategies, photophysical properties of TTA-based materials (both blue emitters and host materials), mechanism of TTA-based electroluminescence, as well as their OLED applications are presented comprehensively. Moreover, potential perspectives with future research opportunities in this field are also described. We believe that the emerging TTA-based materials will bring more opportunities for developing a large family of novel photofunctional materials showing appealing and tunable photophysical properties, thus providing new opportunities for high-efficiency and stable blue electroluminescence in the future.

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“…Inspired by this method, more APO-based emitters with improved rigidity have been reported. 32,42,[44][45][46][47][48][49] Among the APO-type moieties, the 9-phenyl-9-phosphafluorene oxide (PhFIOP) group can possess inherent advantages of a highly rigid structure to furnish improved opto-electronic properties. Recently, we have introduced electron-donors to the 2-and 8-positions of the PhFIOP unit to construct new green TADF emitters showing high electroluminescence (EL) efficiencies of 23.3%, 83.7 cd A À1 , 59.1 lm W À1 for Z ext , Z L , and Z P , respectively, indicating its great potential for developing highly efficient TADF emitters.…”

Section: Introductionmentioning

confidence: 99%

Blue emitters with various electron-donors attached to the 9-phenyl-9-phosphafluorene oxide (PhFIOP) moiety and their thermally activated delayed fluorescence (TADF) behavior

Chen

Liu

Sun

et al. 2023

Mater. Chem. Front.

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High-efficiency hyperfluorescent white light-emitting diodes based on high-concentration-doped TADF sensitizer matrices via spatial and energy gap effects

Abstract: A thermally activated delayed fluorescence host was developed to realize high-efficiency fluorescence white organic light-emitting diodes (WOLED) through spatial and energy gap effects.

Cited by 17 publications

References 56 publications

White Light Emission Achieved by Dual-TADF in a Single Emissive Layer of Multicomponent Emitters

White Light Emission Achieved by Dual-TADF in a Single Emissive Layer of Multicomponent Emitters

Recent Advances in Triplet–Triplet Annihilation-Based Materials and Their Applications in Electroluminescence

Blue emitters with various electron-donors attached to the 9-phenyl-9-phosphafluorene oxide (PhFIOP) moiety and their thermally activated delayed fluorescence (TADF) behavior

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