<i>Ortho</i>‐Carborane Decorated Multi‐Resonance TADF Emitters: Preserving Local Excited State and High Efficiency in OLEDs

Lee, Taehwan; Jang, Jee‐Hun; Nguyen, Nhi Ngoc Tuyet; Jung, Jaehoon; Lee, Jeong‐Hwan; Lee, Min Hyung

doi:10.1002/advs.202309016

Cited by 6 publications

(1 citation statement)

References 41 publications

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“…Despite the widespread interest in carboranyl emitters, only a couple of NIR emissive compounds have been reported, and they suffer from very low PLQY. , Likewise, there are surprisingly few accounts of carboranyl compounds in OLED devices. − In this work, we utilize the AIE properties of a polymer ( o CbT 2 -IDT) incorporating ortho -carborane directly in the conjugated backbone to achieve a λ PL at 734 nm and a remarkable solid-state PLQY of 13.4%. Furthermore, we observe contrasting behavior in the respective para and meta isomers ( p CbT 2 -IDT and m CbT 2 -IDT), which emit in the visible region and undergo ACQ.…”

Section: Introductionmentioning

confidence: 99%

A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared

Aniés,

Hamilton,

De Castro

et al. 2024

J. Am. Chem. Soc.

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Materials exhibiting aggregation-induced emission (AIE) are both highly emissive in the solid state and prompt a strongly red-shifted emission and should therefore pose as good candidates toward emerging near-infrared (NIR) applications of organic semiconductors (OSCs). Despite this, very few AIE materials have been reported with significant emissivity past 700 nm. In this work, we elucidate the potential of orthocarborane as an AIE-active component in the design of NIR-emitting OSCs. By incorporating ortho-carborane in the backbone of a conjugated polymer, a remarkable solid-state photoluminescence quantum yield of 13.4% is achieved, with a photoluminescence maximum of 734 nm. In contrast, the corresponding para and meta isomers exhibited aggregation-caused quenching. The materials are demonstrated for electronic applications through the fabrication of nondoped polymer light-emitting diodes. Devices employing the ortho isomer achieved nearly pure NIR emission, with 86% of emission at wavelengths longer than 700 nm and an electroluminescence maximum at 761 nm, producing a significant light output of 1.37 W sr −1 m −2 .

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Section: Introductionmentioning

confidence: 99%

A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared

Aniés,

Hamilton,

De Castro

et al. 2024

J. Am. Chem. Soc.

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Peripheral Substitution Engineering of MR‐TADF Emitters Embedded With B‒N Covalent Bond Towards Efficient BT.2020 Blue Electroluminescence

Wan,

Zhou,

Yang

et al. 2024

Advanced Materials

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Compared with the classical boron/nitrogen (B/N) doped ones, multiple‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters embedded with B–N covalent bond behave a significantly blue‐shifted narrowband TADF, and thus show a greater potential in ultrapure blue organic light‐emitting diodes (OLEDs). As a proof of concept, herein a peripheral substitution engineering is demonstrated based on such a B‒N embedded parent core. The simple approach is found to ensure easy synthesis via a one‐pot lithium‐free borylation‐annulation, manipulate the excited states through different electronic coupling between core and substituent, and introduce the steric hindrance to minimize the unwanted spectral broadening. Impressively, ultrapure blue OLEDs are realized to give a high external quantum efficiency of 20.3% together with Commission Internationale de l’Éclairage coordinates of (0.152, 0.046). The performance is well competent with those of B/N doped MR‐TADF emitters, clearly highlighting that the B‒N embedded framework is a novel promising paradigm towards efficient BT.2020 blue standard.

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A Hot Exciton Luminogen Constructed by an o‐Carborane Scaffold

Yu,

Xu,

Wang

et al. 2024

Advanced Optical Materials

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Emitters with the combination of an electron donor (D) and an acceptor (A) have been widely studied and usually exhibited interesting photophysical properties. Hot exciton materials involving an ordinary D‐A structure typically undergo a hybridized local charge transfer (HLCT) process. However, the hot exciton molecules containing more D/A fragments are much less explored. In this study, a new hot exciton material based on an inorganic boron cluster is designed and synthesized, which possesses a V‐type D–A–A′–D′ molecular architecture. The emitter shows an impressive photoluminescence quantum yield (PLQY) of up to 90% and demonstrates multiple emissions, excitation‐wavelength‐, solvent‐, and temperature‐dependent emissions. These characteristics are attributed to the coexistence of HLCT and the through‐space charge transfer process (TSTC) triggered by an o‐carborane scaffold in the excited state. Besides, the interchangeable HLCT/TSCT/hRISC processes are demonstrated by temperature‐dependent spectra and femtosecond time‐resolved transient absorption spectra. These findings confirm a novel hot exciton mechanism, simultaneously induced by HLCT and TSCT. This is also the first example of a carborane‐based hot exciton molecule. The current study not only reports a new molecular architecture for a hot exciton material but also gives rise to a new insight into the hot exciton mechanism.

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Ortho‐Carborane Decorated Multi‐Resonance TADF Emitters: Preserving Local Excited State and High Efficiency in OLEDs

Cited by 6 publications

References 41 publications

A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared

A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared

Peripheral Substitution Engineering of MR‐TADF Emitters Embedded With B‒N Covalent Bond Towards Efficient BT.2020 Blue Electroluminescence

A Hot Exciton Luminogen Constructed by an o‐Carborane Scaffold

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