An efficient pure blue organic light-emitting device with low driving voltages

An efficient pure blue organic light emitting device (OLED) with low driving voltages was constructed by using a hole-blocking/electron transport layer for carrier and exciton confinement and a bilayer cathode of LiF/MgAg. Indium tin oxide-coated glass with a sheet resistance of about 100 ω/square was used as the substrate for OLEDs. α-napthylphenylbiphenyl diamine, DNA, and tris-(8-hydroxyquinoline) aluminum were used as the hole transport layer, emissive layer and the electron-transport layer respectively. With a 9nm thick doped DNA emissive layer, a current density of 20 mA/cm² was achieved at 5.5 V with a luminance of 680 cd/m².