Thermally Activated Delayed Fluorescent Organic Light Emitting Diodes: Solution Processed to Printed

Organic light emitting diodes (OLEDs) have progressed immensely, enabled by the different generations of light emitting materials. The latest generation of light emitting materials for OLEDs are the thermally activated delayed fluorescent (TADF) emitters and there has been significant effort in making solution processable TADF emitters, which has led to printable TADF OLEDs. This review provides an analysis of the current state-of-the-art solution processed TADF OLEDs including white-OLEDs. We find that fully solution processed TADF OLEDs, where all the organic layers are solution processed, account for only approximate to 4% of the reported solution processed TADF OLEDs. We also evaluate the progress of printed TADF OLEDs, examining the state-of-the-art performances, different emissive materials and the similarities and differences in the device structures used. Our analysis reveals that the majority of the printing for TADF OLEDs is through inkjet printing and their emission peaks predominantly fall within the 500 nm to <600 nm. We conclude with proposals of potential areas for further research for the development of cheaper and scalable OLEDs.