Highly efficient dual-core derivatives with EQEs as high as 8.38% at high brightness for OLED blue emitters†
Three blue fluorescent materials were newly synthesized by attaching triphenylamine side groups at their ortho, meta, and para positions to a dual core moiety of anthracene and pyrene, two chromophores with good luminous efficiency; these three materials were 2-(6-(10-(2-(diphenylamino)phenyl)anthracen-9-yl)pyren-1-yl)-N,N-diphenylaniline (o-TPA-AP-TPA), 3-(6-(10-(3-(diphenylamino)phenyl)anthracen-9-yl)pyren-1-yl)-N,N-diphenylaniline (m-TPA-AP-TPA), and 4-(6-(10-(4-(diphenylamino)phenyl)anthracen-9-yl)pyren-1-yl)-N,N-diphenylaniline (p-TPA-AP-TPA), respectively. The optical, thermal, and electroluminescence (EL) properties of the synthesized materials were measured. All three materials were found to be real blue emitters in the solution state and display high PLQY values. A device doped with p-TPA-AP-TPA displayed a very high efficiency of 9.14 cd A−1 and an EQE of 8.38% at a high luminance of 5000 cd m−2.