No abstract

The effect of LiF thickness on the electrical and luminescent characteristics in OLEDs has been studied by carefully varying thickness value range from 0 nm to 1.2 nm. It's interesting to find that the device with 0.2 nm LiF layer performs the largest current and comparative lower luminescent efficiency, while the one with 0.6 nm LiF performs another current peak (lower than that of device with 0.2 nm LiF layer) but the highest luminescent efficiency in all devices. Here the much enhanced electron injection and destructive efficiency for 0.2 nm LiF device are understood by the chemical interaction model at cathode interface, while the fairly increased electron injection and much improved efficiency for 0.6 nm LiF device would be interpreted by other mechanisms, and LiF plays a protective part in preventing the deposition-induce photoluminescence from quenching by Al cathode.