An organic/organic interface, like an electrode/organic interface in an organic light-emitting diode (OLED), can be severely affected by ambient contamination. However, we surprisingly found that the contaminated surface or interface can be “cured” by depositing a thin interfacial layer containing a strong reducing agent onto the contaminated surface before finishing the fabrication of the device. For example, in comparison with a regular OLED, an OLED having a 5-min ambient exposure to the light-emitting layer/electron-transporting layer interface drops its initial electroluminescence (EL) intensity by 50%. The decreased EL intensity due to the 5-min ambient exposure can be fully recovered and the improved operational stability can be realized after curing the contaminated interface using a thin Li interfacial layer. The experimental results provide a useful method to cope with the interfacial contamination in OLEDs during a manufacturing process. In addition, our results support the failure mechanism of an Alq-based OLED suggested by [Papadimitrakopoulos et al, Chem. Mater. 8, 1363 (1996)].
Recoverable electroluminescence from a contaminated organic/organic interface in an organic light-emitting diode
L. S. Liao, K. P. Klubek, J. K. Madathil, C. W. Tang, D. J. Giesen; Recoverable electroluminescence from a contaminated organic/organic interface in an organic light-emitting diode. Appl. Phys. Lett. 25 January 2010; 96 (4): 043302. https://doi.org/10.1063/1.3294324
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