Recent advances in flexible organic light-emitting diodes

The emergence of smartphones and televisions with curved displays indicates that flexible organic light-emitting diodes (OLEDs) are marching steadily toward commercialization. Regardless of the significant step forward from laboratory to industry, flexible OLEDs are still facing enormous obstacles and challenges in realizing truly wearable, deformable, printable and low-cost electronic products for the future. How to develop highly flexible electrodes, optimize the device efficiency and greatly extend the operation lifetime are among the most important issues to be solved. In this regard, this review summarizes the recent achievements in flexible transparent conductive electrodes, device fabrication as well as light extraction technologies. Furthermore, the device operation stability is discussed with a focus on device degradation mechanisms and encapsulation methods. Some future prospects on new opportunities and research challenges in flexible OLEDs are also covered.