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Current research on organic light emitters which utilize multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is gaining significant interest because of the materials' ability to efficiently generate color-pure blue emission. However, the underlying reasons for high color purity remain unclear. It is shown here that these emitters share a common electronic basis, which is deduced from resonance structure considerations following Clar's rule, and which is termed as "poly-heteroaromatic omni-delocalization" (PHOD). The simple and clear design rules derived from the PHOD concept allow extending the known chemical space by new structural motifs. Based on PHOD, a set of novel high-efficiency color-pure emitters with brilliant deep-blue hue is specifically designed.
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http://dx.doi.org/10.1002/adma.202404388 | DOI Listing |
J Phys Chem A
February 2025
Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid 28049, Spain.
The quest for color-pure emitters for multicolor bioimaging as well as for ultrahigh definition organic light-emitting diodes demands facile design concepts to avoid tedious synthetic or computational trial-and-error procedures. We have recently presented a simple recipe to construct color-pure blue emitters, which combines basic resonance structure and frontier molecular orbital treatments; this recipe applies to multiresonant type emitters and allows to enlarge the chemical space toward novel structural motifs. In the current work, we show that such fundamental considerations further apply to the structurally entirely different family of xanthene dyes.
View Article and Find Full Text PDFAdv Mater
September 2024
Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid, 28049, Spain.
Current research on organic light emitters which utilize multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is gaining significant interest because of the materials' ability to efficiently generate color-pure blue emission. However, the underlying reasons for high color purity remain unclear. It is shown here that these emitters share a common electronic basis, which is deduced from resonance structure considerations following Clar's rule, and which is termed as "poly-heteroaromatic omni-delocalization" (PHOD).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2023
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
Chiral boron/nitrogen doped multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising for highly efficient and color-pure circularly polarized organic light-emitting diodes (CP-OLEDs). Herein, we report two pairs of MR-TADF materials (Czp-tBuCzB, Czp-POAB) based on planar chiral paracyclophane with photoluminescence quantum yields of up to 98 %. The enantiomers showed symmetric circularly polarized photoluminescence spectra with dissymmetry factors |g | of up to 1.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2020
Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Thermally activated delayed fluorescence (TADF) sensitization of fluorescence is a promising strategy to improve the color purity and operational lifetime of conventional TADF organic light-emitting diodes (OLEDs). Here, we propose a new design strategy for TADF-sensitized fluorescence based on acrylic polymers with a pendant energy-harvesting host, a TADF sensitizer, and fluorescent emitter monomers. Fluorescent emitters were rationally designed from a series of homologous polycyclic aromatic amines, resulting in efficient and color-pure polymeric fluorophores capable of harvesting both singlet and triplet excitons.
View Article and Find Full Text PDFFront Chem
May 2020
Department of Chemistry and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Jinju-si, South Korea.
Organic light-emitting diodes with thermally activated delayed fluorescence emitter have been developed with highly twisted donor-acceptor configurations and color-pure blue emitters. Synthesized 4-(4-(4,6-diphenylpyrimidin-2-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene] (4,6-PhPMAF) doped device with spiroacridine as a donor unit and diphenylpyrimidine as acceptor exhibits the device characteristics such as the luminescence, external quantum efficiencies, current efficiencies, and power efficiencies corresponding to 213 cd/m, 2.95%, 3.
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