OLED & PLED Materials

The organic light-emitting diode (OLED) is a high-performance optoelectronic device consisting of charge transport and emissive organic layers. Upon applied voltage, the dual carrier injection system of the OLED supplies both electrons and holes to the electroluminescent material between two electrodes, resulting in its characteristic electroluminescent light with specific color and device performance, depending on the organic materials employed in the device.

The two main classes of OLEDs include small-molecule based light emitting diodes and polymer-based light emitting diodes (PLEDs). A typical double-heterostructure small-molecule OLED consists of three organic layers sandwiched between electrodes. The organic layers adjacent to the cathode and anode are the electron transport layer (ETL) and the hole transport layer (HTL), respectively. The emissive layer (EML) usually consists of light-emitting dyes or dopants dispersed in a suitable host material (often HTL or ETL material). PLEDs have relatively simple architectures, with the light-emitting polymer (LEP) layer combining host, emitter and charge transport functions in a single solution-processed layer of the device.