Two independent studies employing the same narrowband deep-blue emitter, ν-DABNA, but different energy transfer schemes, achieve efficient and stable deep-blue electroluminescence.
Ionic iridium(III) complexes are emerging with great promise for organic electronic devices, owing to their unique features such as ease of molecular design and synthesis, excellent photophysical ...properties, superior redox stability, and highly efficient emissions of virtually all colors. Here, recent progress on new material design, regarding photo‐ and electroluminescence is highlighted, including several interesting topics such as: i) color‐tuning strategies of cationic iridium(III) complexes, ii) widespread utilization in phosphorescent light‐emitting devices fabricated by not only solution processes but also vacuum evaporation deposition, and iii) potential applications in data record, storage, and sercurity. Results on anionic iridium(III) complexes and “soft salts” are also discussed, indicating a new related subject. Finally, a brief outlook is suggested, pointing out that ionic iridium(III) complexes should play a more significant role in future organic electronic materials technology.
Ionic iridium(III) complexes show high promise for organic electronic devices owing to their excellent luminescence of virtually all colors. Recent progress on material design, characterization, and applications of ionic iridium(III) complexes is highlighted, pointing out their great potential for future organic displays, lighting, and data record storage.
Featuring a combination of ultrathin and lightweight properties, excellent mechanical flexibility, low power‐consumption, and widely tunable saturated emission, flexible displays have opened up a new ...possibility for optoelectronics. The demands for flexible displays are growing on a continual basis due not only to their successful commercialization but, more importantly, their endless possibilities for wearable integrated systems. Up to now, self‐emissive technologies for displays, flexible active‐matrix organic light‐emitting diodes (flex‐AMOLED), flexible quantum dot light‐emitting diodes (flex‐QLEDs), and flexible perovskite light‐emitting diodes (flex‐PeLEDs) have been widely reported, but despite the significant progress made in these technologies, enormous obstacles and challenges remain for the vision of truly wearable applications, in particular with flex‐QLEDs and flex‐PeLEDs. Here, a review of the recent progress of all three self‐emissive technologies for flexible displays is conducted, including the emissive active materials, device structures and approaches to manufacturing, the flexible substrates, and conductive electrodes, as well as the encapsulation techniques. The fast‐paced improvement made to the efficiency of flexible devices in recent years is also summarized. The review concludes by making suggestions on the future development in this area, and is expected to help researchers in gaining a comprehensive understanding about the newly emerging technologies for flexible displays.
The progress of self‐emissive techniques for flexible displays is reviewed, beginning with emitting active materials and device fabrication technologies, followed by flexible substrates, transparent electrodes, and encapsulation, and then the rapid development of the performance of devices.
Gelatinous underwater invertebrates such as jellyfish have organs that are transparent, luminescent and self-healing, which allow the creatures to navigate, camouflage themselves and, indeed, survive ...in aquatic environments. Artificial luminescent materials that can mimic such functionality can be used to develop aquatic wearable/stretchable displays and water-resistant devices. Here, a luminescent composite that is simultaneously transparent, tough and can autonomously self-heal in both dry and wet conditions is reported. A tough, self-healable fluorine elastomer with dipole-dipole interactions is synthesized as the polymer matrix. It exhibits excellent compatibility with metal halide perovskite quantum dots. The composite possesses a toughness of 19 MJ m
, maximum strain of 1300% and capability to autonomously self-heal underwater. Notably, the material can withstand extremely harsh aqueous conditions, such as highly salty, acidic (pH = 1) and basic (pH = 13) environment for more than several months with almost no decay in mechanical performance or optical properties.
High‐color‐purity emissions with small a full‐width at half‐maximum (FWHM) are an ongoing pursuit for high‐resolution displays. Though the flourishment of narrow‐band emissive materials with ...multi‐resonance induced thermally activated delayed fluorescence (MR‐TADF) in the blue region, such materials have not validated their potential in other color regions. By amplifying the influence of skeleton and peripheral units, a series of highly efficient green‐emitting MR‐TADF materials are firstly reported. Peripheral units with electron‐deficit properties can significantly narrow the energy gap for bathochromic emission without compromising the color fidelity. MR‐TADF emitters with photo‐luminance quantum yields of above 90 % with FWHMs of ≤25 nm are developed. The corresponding organic light‐emitting diodes show maximum external quantum efficiency/ power efficiency of 22.02 %/ 69.82 lm W−1 with excellent long‐term stability.
By amplifying the influence of the skeleton and peripheral acceptor units, a series of highly efficient green‐emitting MR‐TADF materials were obtained. MR‐TADF emitters with photo‐luminance quantum yields of above 90 % with full width at half maxima of ≤25 nm were realized. The corresponding organic light‐emitting diodes show maximum external quantum efficiency/ power efficiency of 22.02 %/ 69.82 lm W−1 with excellent long‐term stability.
Bright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue ...emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content needed to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue light-emitting diodes based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.
NIR-II fluorophores have shown great promise for biomedical applications with superior in vivo optical properties. To date, few small-molecule NIR-II fluorophores have been discovered with ...donor-acceptor-donor (D-A-D) or symmetrical structures, and upconversion-mitochondria-targeted NIR-II dyes have not been reported. Herein, we report development of D-A type thiopyrylium-based NIR-II fluorophores with frequency upconversion luminescence (FUCL) at ~580 nm upon excitation at ~850 nm. H4-PEG-PT can not only quickly and effectively image mitochondria in live or fixed osteosarcoma cells with subcellular resolution at 1 nM, but also efficiently convert optical energy into heat, achieving mitochondria-targeted photothermal cancer therapy without ROS effects. H4-PEG-PT has been further evaluated in vivo and exhibited strong tumor uptake, specific NIR-II signals with high spatial and temporal resolution, and remarkable NIR-II image-guided photothermal therapy. This report presents the first D-A type thiopyrylium NIR-II theranostics for synchronous upconversion-mitochondria-targeted cell imaging, in vivo NIR-II osteosarcoma imaging and excellent photothermal efficiency.
White organic light‐emitting diodes (WOLEDs) with thermally activated delayed fluorophor sensitized fluorescence (TSF) have aroused wide attention, considering their potential for full exciton ...utilization without noble‐metal containing phosphors. However, performances of TSF‐WOLEDs with a single‐emissive‐layer (SEL) still suffer from low exciton utilization and insufficient blue emission for proper white balance. Here, by modulating Förster and Dexter interactions in SEL‐TSF‐WOLEDs, high efficiencies, balanced white spectra, and extended lifetimes are realized simultaneously. Given the different dependencies of Förster and Dexter interactions on intermolecular distances, sterically shielded blue thermally activated delayed fluorescence (TADF) emitters and orange conventional fluorescent dopants (CFDs) with electronically inert peripheral units are adopted to enlarge distances of electronically active chromophores, not only blocking the Dexter interaction to prevent exciton loss but also finely suppressing the Förster one to guarantee balanced white emission with sufficient blue components. It thus provides the possibility to maximize device performances in a large range of CFD concentrations. A record high maximum external quantum efficiency/power efficiency of 19.6%/52.2 lm W−1, Commission Internationale de L'Eclairage coordinate of (0.33, 0.45), and prolonged half‐lifetime of over 2300 h at an initial luminance of 1000 cd m−2 are realized simultaneously for SEL‐TSF‐WOLEDs, paving the way toward practical applications.
Single‐emissive‐layer all fluorescent white organic light‐emitting diodes yield a record high external quantum efficiency of 19.6%, power efficiency of 52.2 lm W−1, and long half‐lifetime of 2304 h simultaneously, by blending a sterically shielded blue emitter with thermally activated delayed fluorescence and orange conventional fluorescent dopants to modulate exciton interactions.
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