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Extending rigid electron-deficient skeletons and appending electron-rich units to build high-efficiency red-emitting pyrene-derived TADF materials.
- Source :
- Journal of Materials Chemistry C; 11/14/2023, Vol. 11 Issue 42, p14876-14883, 8p
- Publication Year :
- 2023
-
Abstract
- In order to develop novel pyrene-derived thermally activated delayed fluorescence (TADF) materials and deeply study their structure–property relationship, two emitters of PyPzCN-TPA<subscript>2</subscript> and PyQlCN-TPA<subscript>2</subscript> were designed and synthesized by alternating dicyano pyrenopyrazine (PyPzCN) and dicyano pyrenoquinoxaline (PyQlCN) as the rigid electron-deficient skeleton, as well as triphenylamine (TPA) as an electron-rich unit anchored at the K-region of pyrene, respectively. The effects of the rigid electron-deficient skeleton and electron-rich unit on photophysical and electroluminescence (EL) properties were primarily studied. The extending rigid electron-deficient skeleton made PyQlCN-TPA<subscript>2</subscript> exhibit red-shifted emission at 658 nm in toluene and 840 nm in its neat film. The appending electron-rich unit at the K-region made both emitters exhibit large steric hindrance with a torsion angle of more than 70°, which resulted in a small ΔE<subscript>ST</subscript> value of about 0.032 eV and a high k<subscript>RISC</subscript> of about 1.6–4.7 × 10<superscript>5</superscript> s<superscript>−1</superscript>. As a result, the solution-processed PyPzCN-TPA<subscript>2</subscript> and PyQlCN-TPA<subscript>2</subscript>-doped OLEDs simultaneously exhibited high EQEs of 9.30% at 588 nm and 8.94% at 630 nm, respectively. The EQE roll-off was efficiently suppressed with an increase of emission wavelength. This is the first time that high-efficiency red-emitting pyrene-derived TADF materials were obtained by extending the rigid electron-deficient skeleton and appending the electron-rich unit at the K-region for solution-processed OLEDs. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507526
- Volume :
- 11
- Issue :
- 42
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry C
- Publication Type :
- Academic Journal
- Accession number :
- 173412251
- Full Text :
- https://doi.org/10.1039/d3tc03390b