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Multi‐Resonance Deep‐Red Emitters with Shallow Potential‐Energy Surfaces to Surpass Energy‐Gap Law**
- Source :
- Angewandte Chemie. 133:20661-20666
- Publication Year :
- 2021
- Publisher :
- Wiley, 2021.
-
Abstract
- Efficient organic emitters in the deep-red region are rare due to the "energy gap law". Herein, multiple boron (B)- and nitrogen (N)-atoms embedded polycyclic heteroaromatics featuring hybridized π-bonding/ non-bonding molecular orbitals are constructed, providing a way to overcome the above luminescent boundary. The introduction of B-phenyl-B and N-phenyl-N structures enhances the electronic coupling of those para-positioned atoms, forming restricted π-bonds on the phenyl-core for delocalized excited states and thus a narrow energy gap. The mutually ortho-positioned B- and N-atoms also induce a multi-resonance effect on the peripheral skeleton for the non-bonding orbitals, creating shallow potential energy surfaces to eliminate the high-frequency vibrational quenching. The corresponding deep-red emitters with peaks at 662 and 692 nm exhibit narrow full-width at half-maximums of 38 nm, high radiative decay rates of ca. 108 s-1 , ≈100 % photo-luminescence quantum yields and record-high maximum external quantum efficiencies of ca. 28 % in a normal planar organic light-emitting diode structure, simultaneously.
Details
- ISSN :
- 15213757 and 00448249
- Volume :
- 133
- Database :
- OpenAIRE
- Journal :
- Angewandte Chemie
- Accession number :
- edsair.doi.dedup.....1c9c7f35b79d35f079f622dfc9e92b74