High performance polymer light-emitting diodes fabricated with a novel hole injection layer
Enhanced luminance (L) and luminous efficiency (LE) of polymer light-emitting diodes (PLEDs) is demonstrated using poly (bis (tetraphenyldiamino)biphenyl-perfluorocyclobutane), poly(BTPD-Si-PFCB), as the hole injection layer. The monomer is cast directly onto the indium-tin-oxide anode and thermally polymerized in situ. Hole injection from poly(BTPD-Si-PFCB) into the Â"super yellowÂ" derivative of poly(phenylene vinylene) and into several blue emitting polymers is comparable to or better than that from poly(enthylendioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSSA). With poly(BTPD-Si-PFCB) as the hole injecting layer into super yellow, the performance is identical to that obtained with PEDOT:PSSA (LE Â» 8 cd/A with little fall-off even at L > 104 cd/m2). For blue-emitting polymers, the use of poly(BTPD-Si-PFCB) leads to significant improvements in L and LE; e.g. with polyfluorene, L and LE are more than an order of magnitude greater than from similar devices made with PEDOT:PSSA.