Bisanthracene- Based Donor- Acceptor- type Light- Emitting Dopants: Highly Effi cient Deep- Blue Emission in Organic Light- Emitting Devices

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 -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.