Transparent organic light-emitting diodes based on Cs2CO3:Ag/Ag composite cathode

The transparent organic light-emitting diodes (TOLEDs) based on Cs2CO3:Ag/Ag composite cathode are reported in this paper. They show higher efficiency and better stability than the control devices with the Cs2CO3/Ag cathode. The devices are highly transparent, and show total efficiencies from both sides of the devices comparable with conventional bottom-emitting devices. The electroluminescence (EL) spectrum from the cathode side of the device is closer to the photoluminescence (PL) spectrum of the light-emitting material than that from the anode side. The effect of the cathode Ag thickness on the device performance has been investigated. It is observed that a critical Ag thickness of 15 nm is required to form a good Ag film with high optical transparency and electrical conductivity.