Bright, efficient, deep blue-emissive polymer light-emitting diodes of suitable hole-transport layer and cathode design

► Efficient PLEDs are obtained by suitable hole-transport layer and cathode design. ► The emissions are centered at 430-450 nm, with CIE coordinates of (0.15, 0.14). ► A maximal brightness and luminous efficiency are 35054.2 cd/m2 and 14.0 cd/A1. ► We conclude that Ca is not a suitable cathode, due to the destruction on polymer. ► And Cs2CO3 is a favorable cathode in fabricating polyflourene-based PLEDs.