A series of green multi-resonance thermally activated delayed fluorescence polymeric emitters featuring conjugation-interrupted main chains were facilely prepared metal-free superacid-catalyzed Friedel-Crafts polyhydroxyalkylation. These emitters exhibited photoluminescence quantum yields of up to 76% and small full-widths at half maximum of 35-38 nm in toluene. The corresponding solution-processed OLEDs achieved an excellent maximum external quantum efficiency of 19.4%, with CIE coordinates of (0.20, 0.62).
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http://dx.doi.org/10.1039/d4cc03349c | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Science and Technology of China, Chemistry and Material Science, No.96, JinZhai Road Baohe District, 230026, Hefei, CHINA.
Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials have great potential for applications in ultrahigh-definition (UHD) organic light-emitting diode (OLED) displays, that benefit from their narrowband emission characteristic. However, key challenges such as aggregation-caused quenching (ACQ) effect and slow triplet-to-singlet spin-flip process, especially for blue MR-TADF materials, continue to impede their development due to planar skeletons and relatively large ΔESTs. Here, an effective strategy that incorporates multiple carbazole donors into the parent MR moieties is proposed, synergistically engineering their excited states and steric hindrances to enhance both the spin-flip process and quenching resistance.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, 03722, Republic of Korea.
1,4-Azaborine-based arenes are promising electroluminescent emitters with thermally activated delayed fluorescence (TADF), offering narrow emission spectra and high quantum yields due to a multi-resonance (MR) effect. However, their practical application is constrained by their limited operational stability. This study investigates the degradation mechanism of MR-TADF molecules.
View Article and Find Full Text PDFChemistry
December 2024
Hebei Key Laboratory of Organic Functional Molecules, Hebei Technology Innovation Center for Energy Conversion Materials and Devices, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, PR China E-mail address.
Hydrogen bonds (HBs), prevalent strong interactions in organic compounds, can effectively constrain single bond rotation, leading to rigid planar configurations. This rigidity enhances emission efficiency and narrows the emission spectrum of luminescent materials. Recent advances have leveraged HBs to advance high-performance donor-acceptor thermally activated delayed fluorescence (TADF) materials.
View Article and Find Full Text PDFChem Sci
November 2024
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China
Unlike boron, nitrogen-containing multi-resonance emitters with thermally activated delayed fluorescence, here we report boron, sulfur (B, S)-based multi-resonance emitters with room-temperature phosphorescence (RTP) by inserting thiophene into a 5,9-dithia-13-boranaphtho[3,2,1-]anthracene skeleton that simultaneously realizes large singlet-triplet energy splitting and strong spin-orbital coupling, leading to efficient room-temperature phosphorescence in an amorphous state. Unlike most RTP emitters with ultraviolet excitation, the multi-resonance RTP emitters exhibit strong phosphorescence under daily-use blue/white LED lamps owing to their intense absorption in the visible-light region (400-486 nm). Meanwhile, such RTP behavior can be tuned by the number and fusing pattern of the thiophene moieties, with the emitters containing thiophene linked to boron atoms α-positions exhibiting bathochromatically shifted emissions and longer phosphorescence lifetimes (47.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, Jiangsu, P. R. China.
Multi-resonance (MR)-type organic emitters are highly attractive in the field of organic light-emitting diodes because of their narrowband emission and thermally activated delayed fluorescence (TADF) properties. Compared with conventional TADF emitters, MR-featured emitters have more complex chemical structures and building logics. The core structures of MR emitters are MR frameworks, , polyaromatic frameworks, precisely embedded with electron-donating and electron-withdrawing atoms/groups.
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