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White organic light-emitting diodes (OLEDs) offer a promising solution for next-generation lighting technologies and their ability to emit white light through various mechanisms make them an attractive option for illumination and display applications. Here, we design and prepare a series of N,N-difluorenevinylaniline-based small molecules and polymer, and realize white OLEDs based on these luminescent materials with combined blue monomer emission and orange electromer emission upon electronic excitation in the solution-processed devices. Impressively, the single-component nonconjugated polymer exhibits the best device performance, because the nonconjugated structure favors good solubility of the polymers, while the conjugated starburst unit functions as highly luminescent fluorophore in both single molecular and aggregated structures for the blue and orange emissions, respectively. Specifically, the non-doped solution-processed OLEDs achieve warm white electroluminescence with a maximum luminance of 1806 cd/m2 and a maximum external quantum efficiency of 2.63%. And, the OLEDs based on the monomer also exhibit white electroluminescence with Commission Internationale de L’Eclairage coordinates of (0.30, 0.32). These results highlight a promising strategy for the material design and preparation of single-component nonconjugated polymers with rich emissive behaviors in solid states towards efficient and solution-processable white OLEDs.

Top-emitting microcavity OLEDs (TEOLEDs) exhibit excellent color purity but suffer from severe angular color shifts. To overcome this, we introduce a nanotextured light modulation strategy using a nanoporous film (NPF) and an index-matched optically clear resin (OCR) for encapsulation. The nanotextured NPF enhances light outcoupling while suppressing cavity-induced angular dependence. As a result, the external quantum efficiency (EQE) is enhanced by 370% (from 8.5 to 31.6%), and angular color shift (Δu′v′) is reduced by 65.2% (from 0.046 to 0.016). By introducing a nanostructure-based light modulation technology, we have achieved a breakthrough in microcavity OLED performance, simultaneously improving both outcoupling and angular stability. Applied to flexible TEOLEDs, the device exhibits stable optical and mechanical performance under bending. This scalable and effective light modulation design enables highly efficient and color-stable flexible OLED displays for next-generation wearable applications.

Although numerous thermally activated delayed fluorescence (TADF) organic light‐emitting diodes (OLEDs) have been demonstrated, efficient blue or even sky‐blue TADF‐based nondoped solution‐processed devices are still very rare. Herein, through‐space charge transfer (TSCT) and through‐bond charge transfer (TBCT) effects are skillfully incorporated, as well as the multi‐(donor/acceptor) characteristic, into one molecule. The former allows this material to show small singlet–triplet energy splitting (ΔEST) and a high transition dipole moment. The latter, on the one hand, further lights up multichannel reverse intersystem crossing (RISC) to increase triplet exciton utilization via degenerating molecular orbitals. On the other hand, the nature of the molecular twisted structure effectively suppresses intermolecular packing to obtain high photoluminescence quantum yield (PLQY) in neat flims. Consequently, using this design strategy, T‐CNDF‐T‐tCz containing three donor and three acceptor units, successfully realizes a small ΔEST (≈0.03 eV) and a high PLQY (≈0.76) at the same time; hence the nondoped solution‐processed sky‐blue TADF‐OLED displays record‐breaking efficiency among the solution process‐based nondoped sky‐blue OLEDs, with high brightness over 5200 cd m−2 and external quantum efficiency up to 21.0%. A novel multi‐(donor/acceptor) thermally activated delayed fluorescence (TADF) molecule with through‐space/‐bond charge transfer is developed. Its nondoped solution‐processed sky‐blue organic light‐emitting diode (OLED) displays high performance with an external quantum efficiency (EQEmax) up to 21.0%, which represents the record‐breaking efficiency among the solution process‐based nondoped sky‐blue OLEDs.

Organic light emitting diode (OLED) technology continues to make strides, particularly in display technology, with costs decreasing and consumer demand growing. Advances are also seen in OLED solid state lighting (SSL) though broad utilization of this technology is lagging. This situation has prompted extensive R&D to achieve high-efficiency SSL devices at cost-effective fabrication. Here we review the advances and challenges in enhancing forward light outcoupling from OLEDs. Light outcoupling from conventional bottom-emitting OLEDs (through a transparent anode) is typically ∼20%, largely due to external losses, i.e., substrate waveguide modes, internal waveguide modes between the metal cathode and the anode/substrate interface, and surface plasmon-polariton modes at the metal cathode/organic interface. We address these major photon loss paths, presenting various extraction approaches. Some approaches are devoid of light extraction structures; they include replacing the commonly used ITO anode, manipulating the refractive index of the substrate and/or organic layers, and evaluating emitters with preferential horizontal transition dipoles. Other approaches include the use of enhancing structures such as microlens arrays, scattering layers and patterned substrates, as well as substrates with various buried structures that are planarized by high index layers. A maximal external quantum efficiency as high as 78% was reported for white planarized OLEDs with a hemispherical lens to extract the substrate mode. Light outcoupling from OLEDs on flexible substrates is also addressed, as the latter become of increasing interest in foldable displays and decorative lighting, with plastic substrates also being evaluated for biomedical, wearable, and automotive applications.

We present the development of multifunctional blue-emission organic light-emitting diodes (OLEDs) using TADF-exciplex materials. These OLEDs exhibit sensitivity to external stimuli and achieve a maximum external quantum efficiency (EQE) of 11.6% through partly liquid processing. This technique allows for large-scale production on arbitrary geometries. The potential multifunctionality of the devices arises from their response to low external magnetic fields (up to 100 mT) with an efficiency up to 2.5% for magnetoconductance, while maximum magneto-electroluminescence effects of 4.1% were detected. We investigated novel aspects, including the utilization of two organic materials without further doping and the investigation of the impact of 2,2ʹ,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1- H -benzimidazole) (TPBi) processing in liquid and vapor form. The insights gained provide a fundamental understanding regarding the applicability of exciplex (EX) materials for fully solution-processed OLEDs through a deliberate omission of doping. Our work represents a significant advancement on the path towards multifunctional OLED technology, with potential applications in cost-efficient, scalable organic full-color displays and advanced sensing system.

Through‐space charge transfer (TSCT) polymers are an attractive class of luminescent polymers with spatial donor/acceptor architecture and thermally activated delayed fluorescence effect, different from conventional luminescent polymers with conjugated donor‐acceptor structure and through‐bond charge transfer emission. Their emission comes from the intramolecular charge transfer by through‐space pathway because the donor and acceptor segments are spatially proximate to each other in each repeating unit but are physically separated by nonconjugated polymer backbone. In this review, recent advances in TSCT polymers with linear, bottlebrush, and dendritic architectures are presented, with the focus on their molecular design, photophysical behavior, and device performance. We hope that this review shall provide a useful insight of new luminescent polymers with TSCT effect for use in solution‐processed organic light‐emitting diodes. Through‐space charge transfer (TSCT) polymers, with spatial donor/acceptor architecture and thermally activated delayed fluorescence effect, represent an attractive approach toward efficient solution‐processed organic light‐emitting diodes. In this review, recent advances in TSCT polymers with linear, bottlebrush, and dendritic architectures are presented, with the focus on their molecular design, photo‐physical behavior, and device performance.

The development and enrichment of high‐performance organic fluorophores that simultaneously possess thermally activated delayed fluorescence (TADF) and aggregation‐induced emission (AIE) properties is going pursued but remains a great challenge due to severe exciton quenching. Herein, a systematical investigation on imidazole moiety has successfully given rise to a series of highly efficient imidazole‐based TADF‐AIE luminogens for the first time. The attachment of two cyano functionalities on imidazole moiety can significantly increase the electron‐withdrawing ability, so as to realize TADF emissions with small singlet‐triplet energy gaps (ΔEST) values. Meanwhile, the installation of a steric hindrance group at N1 position of imidazole moiety can twist the geometry between imidazole and phenyl bridge, thus transforming imidazole derivative from an aggregation‐caused quenching emitter into an AIE luminogen. Consequently, the non‐doped organic light‐emitting diodes (OLEDs) utilizing these TADF‐AIE luminogens as emitters exhibit outstanding sky‐blue and green emissions, with external quantum efficiency (EQE) as high as 20.0% and low efficiency roll‐off (EQE at 1000 cd m−2, 16.1%). These values represent the state‐of‐the‐art performance for all imidazole‐based OLED devices, which illustrates the significant potential of imidazole derivatives in assembling high‐performance OLEDs. The first example of imidazole‐based TADF‐AIE luminogen has been developed, which exhibits state‐of‐the‐art OLED performance with EQEmax as high as 20.0% and impressively low efficiency roll‐off.

Neonatal jaundice is a very common disease in newborns and can lead to brain damage or death in severe cases. Phototherapy with light‐emitting diode (LED) arrays is widely used as the easiest and fastest way to relieve jaundice in newborns, but it has distinct disadvantages such as loss of water in the patient, damage to the retina, and separation from parents. In this paper, a novel light source‐based phototherapy for neonatal jaundice is proposed using a textile‐based wearable organic light‐emitting diode (OLED) platform that can move flexibly and conform to the curvature of the human body. The soft and flexible textile‐based blue OLED platform is designed to have a peak wavelength of 470 nm, suitable for jaundice treatment, and shows performance (>20 µW cm−2 nm−1) suitable for intensive jaundice treatment even at low voltage (<4.0 V). The textile‐based OLEDs fabricated in this study exhibit an operating reliability of over 100 h and low‐temperature operation (<35 °C). The results of an in vitro jaundice treatment test using a large‐area blue OLED confirm that the bilirubin level decreases to 12 mg dL−1 with 3 h of OLED irradiation. Kyung Cheol Choi et al. develops a novel light source‐based photomedical approach for neonatal jaundice treatment, using a textile‐based wearable organic light‐emitting diode (OLED) platform that can move flexibly and conform to the curvature of the human body. The effectiveness of the blue OLED jaundice treatment is verified by in vitro test, and effective and uniform treatment performance is confirmed. 

Organic light-emitting diodes (OLEDs) offer lucrative advantages in screening and illuminating technologies, including high luminance, design flexibility and energy efficiency. However, commercial adoption is hindered by challenges like device degradation and efficiency roll-off, especially under thermal and electrical stress. This review focuses on the application of lanthanide-based materials in OLEDs, emphasizing their unique photophysical properties and roles as emissive dopants and buffer layers. Lanthanide complexes such as europium(III), samarium(III), terbium(III) and cerium(III) possess unique photophysical properties that enhance exciton confinement, reduce polaron–exciton annihilation and improve radiative efficiency. Ligand systems, including β-diketonates, phenanthroline derivatives, scorpionate frameworks and boron-containing ligands, further support high triplet-energy transfer, improved solubility and efficient charge balance within host–dopant architectures. Europium-based emitters demonstrate reduced roll-off and improved luminance. Additionally, cerium(III) complexes show ultrafast excited-state lifetimes and near-unity quantum yields. Metal alloys incorporating ytterbium and its oxides act as superior buffer layers in cathodes that can inhibit the penetration of moisture and oxygen, enhancing both transparency and lifetime. Yb-based cathodes and interlayers, especially in combinations like Yb/Ag or LiF/Yb/Ag, enable efficient electron injection and mitigate degradation through improved stability. These innovations collectively address core issues in OLED performance, laying the foundation for highly durable, high-brightness and flexible optoelectronic devices.

Narrowband emissive multiple resonance (MR) emitters promise high efficiency and stability in deep‐blue organic light‐emitting diodes (OLEDs). However, the construction of ideal ultra‐narrow‐band deep‐blue MR emitters still faces formidable challenges, especially in balancing bathochromic‐shift emission, spectral narrowing, and aggregation suppression. Here, DICz is chosen, which possesses the smallest full‐width‐at‐half‐maximum (FWHM) in MR structures, as the core and solved the above issue by tuning its peripheral substitution sites. The 1‐substituted molecule Cz‐DICz is able to show a bright deep‐blue emission with a peak at 457 nm, an extremely small FWHM of 14 nm, and a CIE coordinate of (0.14, 0.08) in solution. The corresponding OLEDs exhibit high maximum external quantum efficiencies of 22.1%–25.6% and identical small FWHMs of 18 nm over the practical mass‐production concentration range (1–4 wt.%). To the best of the knowledge, 14 and 18 nm are currently the smallest FWHM values for deep‐blue MR emitters with similar emission maxima under photoluminescence and electroluminescence conditions, respectively. These discoveries will help drive the development of high‐performance narrowband deep‐blue emitters and bring about a revolution in OLED industry. Toward the goal of ideal ultra‐narrow‐band deep‐blue emitters, a novel “decoration strategy” is proposed to balance the bathochromic‐shift emission, spectral narrowing, and aggregation suppression. The optimized OLEDs exhibit high maximum external quantum efficiencies of 22.1%−25.6% with similar emissions at ≈461 nm and identical small full‐width‐at‐half‐maxima of 18 nm in the practical mass‐production concentration range (1–4 wt.%).