Power-law-type electron injection through lithium fluoride nanolayers in phosphorescence organic light-emitting devices.

This work reports a power-law-type electron injection model that accounts for the thickness effect of lithium fluoride (LiF) nanolayers used as an electron injection layer in phosphorescence organic light-emitting devices (PHOLEDs). A series of PHOLEDs were fabricated with various LiF thicknesses in order to investigate the influence of LiF nanolayer thickness on the device current. The PHOLEDs exhibited pronouncedly changed electron currents by only 0.2 nm thickness variation. The device current as a function of LiF thickness excellently followed the power-law model proposed in this study, from which a physical constant indicating the intrinsic nature of electron injection materials has been extracted.