A degradation mechanism of organic light-emitting devices

A novel mechanism is revealed for the degradation and failure of the recently developed organic light-emitting device (OLED) made of indium-tin oxide (ITO)/poly(p-phenylenevinylene)/aluminum (or magnesium). A main obstacle to obtaining a long lifetime for these devices is found to be the electrochemical reaction on interfaces of both electron and hole injecting electrodes. As a result, the electrode materials are not only degraded, but they also form a complex with the bulk polymer which serves as a ‘weak electrolyte’.