Highly efficient blue fluorescent organic light-emitting diodes by engineering hole-transporting/exciton-blocking layer

This paper reports low-voltage and high power efficiency blue fluorescent organic light-emitting diodes (FLOLEDs) using 4,4-bis[4- (di-4-tolylamino)styryl]biphenyl (DPAVBi) as a fluorescent dye and 9,10-di(naphth-2-yl)anthracene (ADN) as a host.We studied the effect of using 1,1-bis{4-[N,N-di(p-tolyl)amino]-phenyl}cyclohexane (TAPC) as an exciton blocking layer in the blue FLOLEDs, and found the formation of electromers in TAPC at high current density. Based on the efforts toward high power efficiency and stability, we fabricated the blue FLOLEDs exhibiting low driving voltages of 2.9 V for 100 cd m^-2and 3.6 V for 1000 cd m^-2, a maximum luminance of 43256 cd m^-2at 6.6 V, and a high power efficiency of 9.7 lm W^-1with reduced efficiency roll-off.