Influence of Thermal Evaporation Substrate Revolution Velocity on Electroluminescence Characteristics of Organic Light Emitting Diodes

In this work, we report the effect of the rotation speed of the deposited substrate on the electroluminescence (EL) efficiency of the organic light-emitting diode (OLED). Because it has been reported that the deposition angle velocity affects the growth of an organic thin film, it is expected that the OLED EL characteristics must be affected depending on the substrate rotation velocity. Thus, in this work, the substrate rotation velocity was altered during the deposition of each organic material. The OLED devices fabricated with different depositing substrate rotation speeds showed different EL characteristics. The film thickness of the organic materials with different substrate rotation speed was carefully controlled. It was confirmed to be the same with a surface profiler and was further field enhanced using a scanning electron microscope. The difference in peak EQE was observed to be greater than 1.5 times. Based on this result, it is possible to conclude that the speed of the rotational deposition system should affect the film characteristics and therefore should be considered an important parameter.