Enhanced lifetime of flexible organic light-emitting diodes by pressure assisted interfacial adhesion

Environmental stability and lifetime are important for the applications of flexible organic light-emitting diodes (OLEDs). This work investigates the effects of external pressure on the stability and lifetime of flexible OLEDs. The experimental results show that external pressure can effectively suppress the formation of dark spots and extend the lifetime of unencapsulated flexible OLEDs (61.8% enhancement at 4 bar), while has almost no influence on the optoelectronic performance. Further characterization and analysis show that the lifetime extension is closely related to the enhancement of the interfacial adhesion between the top metal cathode and the organic layer under pressure, which could inhibit interfacial delamination. The work reported here is not only able to improve the intrinsic stability of flexible OLEDs, but also has high compatibility with current encapsulation process for commercial applications.