A polymer LED is a type of OLED that uses polymers as a semiconducting material to produce very thin LEDs that can be used for many applications such as flexible displays, indoor lighting, and for medical technology applications such as light sources for lab-on-a-chip devices.
Polymer LEDs are produced by sandwiching electroluminescent polymers between a metal cathode and a transparent anode.
A polymer LED is also known as a PolyLED or a Light-Emitting Polymer (LEP).
Techopedia explains Polymer LED (PLED)
Polymer LEDs have the advantage of being easily manufactured compared to traditional inorganic LEDs. An inorganic semiconductor has to be processed within a vacuum, and extreme care must be taken in preparing materials for LEDs for wavelengths in the blue range. On the other hand, polymeric materials are very easy to process as they can be generated at ambient pressure through dip coating, rolling, spin coating and new inkjet fabrication methods that simply allow for printing of the polymer emitters into the substrate.
Despite the distinct advantages of polymer LEDs, this is still a new technology that has many problems to work out, such as durability. For example, there is still color shift, particularly for blue, which degrades faster. The pixels themselves also have to be encapsulated from air to prevent degradation by oxygen, which takes away from their flexibility quite a bit.