Polymer light-emitting diodes with doped charge transport layers

PhD ceremony: Mr. M. Lu, 14.30 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Polymer light-emitting diodes with doped charge transport layers

Promotor(s): prof. P.W.M. Blom

Faculty: Mathematics and Natural Sciences

Currently, state-of-the-art polymer light-emitting diodes (PLEDs) consist of only one active layer that governs all the processes in the PLED; charge injection, transport and recombination. Due to the typical low mobility of these light-emitting polymers, devices have to be processed with relative low layer thicknesses of ~100 nm. Fabrication techniques such as inkjet printing and roll-to-roll processing are extremely difficult to operate in such a small process window and uniform layer thicknesses of ~100 nm are difficult to achieve with these techniques. Inevitably, bulk processing techniques are very susceptible to short circuits.

A way to solve these issues is the fabrication of multilayer PLEDs in which injection layers are responsible for the injection of electrons and holes and confine the charges in the emissive layer. Using doping these layers can then be made highly conductive, allowing thicker layers and reducing short circuits.