High Stability White Organic Light-Emitting Diode (WOLED) Using Nano-Double-Ultra Thin Carrier Trapping Materials

The structure of indium tin oxide (ITO) (100 nm)/molybdenum trioxide (MoO3) (15 nm)/N,N0-bis-(1-naphthyl)-N,N0-biphenyl-1,10-biphenyl-4,40-diamine (NPB) (40 nm)/4,4′-Bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi) (10 nm)/5,6,11,12-tetraphenylnaphthacene (Rubrene) (0.2 nm)/DPVBi (24 nm)/Rubrene (0.2 nm)/DPVBi (6 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen): cesium carbonate (Cs2Co3) (10 nm)/Al (120 nm) with high color purity and stability white organic light-emitting diode (WOLED) was fabricated. The function of the multiple-ultra-thin material (MUTM), such as Rubrene, is as the yellow light-emitting layer and trapping layer. The results show that the MUTM has an excellent carrier capture effect, resulting in high color stability of the device at different applied voltages. The Commissions Internationale De L’Eclairage (CIE) coordinate of this device at 3~7 V is few displacement and shows a very slight variation of (±0.01, ±0.01). The maximum brightness of 9986 cd/m2and CIE coordinates of (0.346, 0.339) are obtained at 7 V. The enhanced performance of the device may result from the direct charge trapping in MUTM and it can be found in the electroluminescence (EL) process.