Life extension of organic LED's by doping of a hole transport layer

We investigated the influence of a series of aromatic hydrocarbon dopants in the hole transport layer on the life of organic light emitting devices (OLED) with the following configuration: ITO/NPB+dopant/Alq3+fluorescent dye/Mg:Ag. The addition of selected dopants to NPB led to an increase in device lifetime by more than an order of magnitude. Half-life, t1/2, of the devices was measured at the current density of J=25 mA/cm2. Device life, at …