Deep-blue emitters that can harvest both singlet and triplet excited states to give high electron-to-photon conversion efficiencies are highly desired for applications in full-color displays and white lighting devices based on organic light-emitting diodes (OLEDs). Thermally activated delayed fluorescence (TADF) molecules based on highly twisted donor-acceptor (D-A) configurations are promising emitting dopants for the construction of efficient deep-blue OLEDs. In this study, a simple and versatile D-A system combining acridan-based donors and pyrimidine-based acceptors has been developed as a new platform for high-efficiency deep-blue TADF emitters. The designed pre-twisted acridan-pyrimidine D-A molecules exhibit small singlet-triplet energy splitting and high photoluminescence quantum yields, functioning as efficient deep-blue TADF emitters. The OLEDs utilizing these TADF emitters display bright blue electroluminescence with external quantum efficiencies of up to 20.4%, maximum current efficiencies of 41.7 cd A, maximum power efficiencies of 37.2 lm W, and color coordinates of (0.16, 0.23). The design strategy featuring such acridan-pyrimidine D-A motifs can offer great prospects for further developing high-performance deep-blue TADF emitters and TADF-OLEDs.
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http://dx.doi.org/10.1039/c6sc03793c | DOI Listing |
Sci Adv
January 2025
Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
The pursuit of boron-based organic compounds with multiresonance (MR)-induced thermally activated delayed fluorescence (TADF) is propelled by their potential as narrowband blue emitters for wide-gamut displays. Although boron-doped polycyclic aromatic hydrocarbons in MR compounds share common structural features, their molecular design traditionally involves iterative approaches with repeated attempts until success. To address this, we implemented machine learning algorithms to establish quantitative structure-property relationship models, predicting key optoelectronic characteristics, such as full width at half maximum (FWHM) and main peak wavelength, for deep-blue MR candidates.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of physical science and technology, ShanghaiTech University, Shanghai 201210, China.
Implanting heteroatoms into organic π-conjugated molecules (OCMS) offered a great opportunity to fine-tune the chemical structures and optoelectronic properties. This work describes a new family of 1,4-azaphosphinines with extended σ-π hyperconjugations. The photophysical studies revealed that azaphosphinines exhibited narrow-band thermally activated delayed fluorescence (TADF) ( full width at half-maximum: 26-40 nm).
View Article and Find Full Text PDFSmall
January 2025
School of Physics and Electronic Science, East China Normal University, Shanghai, 200062, P. R. China.
Multiple resonance (MR)-type thermally activated delayed fluorescence (TADF) emitters have garnered significant interest due to their narrow full width at half maximum (FWHM) and high electroluminescence efficiency. However, the planar structures and large singlet-triplet energy gaps (ΔEs) characteristic of MR-TADF molecules pose challenges to achieving high-performance devices. Herein, two isomeric compounds, p-TPS-BN and m-TPS-BN, are synthesized differing in the connection modes between a bulky tetraphenylsilane (TPS) group and an MR core.
View Article and Find Full Text PDFNat Commun
January 2025
The Organic Photonics and Electronics Group, Department of Physics, Umeå University, Umeå, Sweden.
The attainment of white emission from a light-emitting electrochemical cell (LEC) is important, since it enables illumination and facile color conversion from devices that can be cost-efficient and sustainable. However, a drawback with current white LECs is that they either employ non-sustainable metals as an emitter constituent or are intrinsically efficiency limited by that the emitter only converts singlet excitons to photons. Organic compounds that emit by thermally activated delayed fluorescence (TADF) can address these issues since they can harvest all excitons for light emission while being metal free.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
School of Materials Science and Engineering, TKL of Metal and Molecule-Based Material Chemistry, Nankai University, Tianjin, 300350, P. R. China.
The application of temperature-compensated photonic device is hampered by poor accuracy and overly simplistic functions of propagation in photonic integrated circuits (PICs) field. Herein, we report a new library of donor-acceptor metal-organic framework (D-A MOF) with thermally activated delayed fluorescence (TADF) and the fabricating of temperature-compensated photonic device by virtue of the unique temperature response character of TADF emitters. Highly tunable through-space charge transfer (TSCT) of TADF was realized within the D-A MOFs through a novel strategy that synergistically combines the internal heavy atom effect (HAE) with an external HAE, induced by the incorporation of heavy atoms into different components, achieving the regulable photophysical indicators including adjustable PL wavelength (534 to 592 nm) and surging quantum yield (5.
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