Efficient and color-saturated inverted bottom-emitting organic light-emitting devices with a semi-transparent metal-assisted electron injection layer

We report the development of highly efficient and color-saturated green fluorescent 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-benzo[l]pyrano-[6,7,8-ij]quinolizin-11-one dye-doped inverted bottom-emitting organic light-emitting diode (IBOLED). This was enabled by the insertion of a silver (Ag) based semi-transparent metal-assisted electron injection layer between the ITO cathode and n-doped electron transporting layer. This IBOLED with ITO/Ag bilayer cathode with its synergistic microcavity effect achieved luminous efficiencies of 20.7 cd/A and 12.4 lm/W and a saturated CIEx,y of (0.22, 0.72) at 20 mA/cm2, which are twice better than those of the conventional OLED and have over 60% improvement on IBOLED without ITO/Ag bilayer cathode.