TY - JOUR T1 - Highly efficient deep-blue fluorescence OLEDs with excellent charge balance based on phenanthro[9,10-d]oxazole-anthracene derivatives A1 - Kang, Seokwoo A1 - Huh, Jin-Suk A1 - Kim, Jang-Joo A1 - Park, Jongwook Y1 - 2020 SP - 11168 EP - 11176 JF - Journal of Materials Chemistry C JO - J. Mater. Chem. C VL - 8 IS - 32 PB - The Royal Society of Chemistry SN - 2050-7526 DO - 10.1039/D0TC01811B M3 - 10.1039/D0TC01811B UR - http://dx.doi.org/10.1039/D0TC01811B N2 - Two blue fluorescent materials, m-PO-ABN and p-PO-ABN, are newly synthesized by controlling the conjugation length based on different linkages of the meta or para position between the phenanthro[9,10-d]oxazole (PO) moiety and anthracene substituted with a cyano group. The two materials emit deep-blue light with a high photoluminescence quantum yield (PLQY) in solution state. Non-doped devices fabricated using m-PO-ABN and p-PO-ABN show the EL peaks at 448 and 460 nm corresponding to the Commission Internationale de L’Eclairage (CIE) coordinates of (0.148, 0.099) and (0.150, 0.164), respectively. The external quantum efficiency (EQE) values of the devices are 5.9% and 5.3% for m-PO-ABN and p-PO-ABN, respectively. Transient EL measurements and optical calculation results reveal that both materials exhibit good charge balance and triplet–triplet annihilation in the devices, which may originate from enhanced bipolar characteristics due to the insertion of PO and cyano moieties. ER -