Recent Progress of Flexible OLEDs for Wearable Devices

Nowadays, flexible organic light-emitting diodes (OLEDs) have been widely used in next-generation wearable electronics. Flexible electrodes, flexible substrates, and flexible encapsulation are indispensable components for the construction of flexible OLEDs. In this review, metal nanowires and graphene-based flexible electrodes, textile (fiber and fabric), novel polymer film-based flexible OLEDs, including the key process of planarization for flexible OLEDs fabrication on uneven surfaces are discussed. OLEDs cannot operate stably without encapsulation in an ambient atmosphere. Not only barrier performance but also mechanical properties are necessary for the encapsulation of flexible OLEDs. The encapsulation technologies for flexible OLEDs fabrication are also described.