Bisanthracene‐Based Donor–Acceptor‐type Light‐Emitting Dopants: Highly Efficient Deep‐Blue Emission in Organic Light‐Emitting Devices

Abstract

Deep‐blue fluorescent compounds are particularly important in organic light‐emitting devices (OLEDs). A donor–accepotor (DA)‐type blue‐emitting compound, 1‐(10‐(4‐methoxyphenyl)anthracen‐9‐yl)‐4‐(10‐(4‐cyanophenyl)anthracen‐9‐yl)benzene (BD3), is synthesized, and for comparison, a nonDA‐type compound, 1,4‐bis(10‐phenylanthracene‐9‐yl)benzene (BD1) and a weak DA‐type compound, 1‐(10‐phenylanthracen‐9‐yl)‐4‐(10‐(4‐cyanophenyl)anthracen‐9‐yl)‐benzene (BD2), are also synthesized. The twisted conformations of the two anthracene units in the compounds, confirmed by single crystal X‐ray analysis, effectively prevent π‐conjugation, and the compound shows deep‐blue photoluminescence (PL) with a high PL quantum efficiency, almost independent of the solvent polarity, resulting from the absence of an intramolecular charge transfer state. The DA‐type molecule BD3 in a non‐doped device exhibits a maximum external quantum efficiency (EQE) of 4.2% with a slight roll‐off, indicating good charge balance due to the DA‐type molecular design. In the doped device with 4,4′‐bis(N‐carbazolyl)‐1,1′‐biphenyl (CBP) host, the BD3 exhibits higher EQE than 10% with Commission International de L'Eclairge (CIE) coordinates of (0.15, 0.06) and a narrow full‐width at half‐maximum of 45 nm, which is close to the CIE of the high definition television standard blue.

Controllable molecular configuration for significant improvement of blue OLEDs based on novel twisted anthracene derivatives

“…In Table 2, The devices p1 and p2 represent 3% and 6% dopant concentration for p-PABPI as the emitting dopant, and the devices m1 and m2 stand for 3% and 6% dopant concentration for m-PABPI as the emitting dopant [31]. Electroluminescent characteristics of the doped devices are also shown in Table 2 and Fig.…”

Efficient Deep Blue Electroluminescence with an External Quantum Efficiency of 6.8% and CIEy < 0.08 Based on a Phenanthroimidazole–Sulfone Hybrid Donor–Acceptor Molecule

“…27 Overall, though a wide range of blue fluorescent materials have been developed, only a few can simultaneously realize NTSC standard deep blue emission as well as an EQE exceeding 5% which is generally considered as the EQE upper limit of fluorescent materials. 24,[27][28][29] Hence, the development of efficient deep blue materials does not progress well. As a result, more efforts should be devoted and deliberate molecular design should be adopted to carry out efficient deep blue emission.…”

Thermally Activated Delayed Fluorescence Emitters for Deep Blue Organic Light Emitting Diodes: A Review of Recent Advances

“…For the small molecular deep-blue emitters, the use of the host material with a larger energy gap is often needed to suppress emission quenching in the devices [68][69][70]. This doping strategy could be the source of inefficient hole and/or electron injection into the emitting layer [71]. In addition, it requires the precise control of the doping concentration, a rather complicated structure, and high fabrication costs.…”