Exploring Device Physics in OLEDs via Magneto-Electroluminescence Study

Magneto-electroluminescence (MEL) refers to the change in the electroluminescence (EL) of a non-magnetic OLED under external magnetic fields. It has aroused extensive research interest since first reported in 2003. After nearly 15 years of study, the underlying mechanisms of MEL have been basically clarified, making the MEL an excellent method for exploring physical processes in OLEDs. In this chapter, using MEL as a tool, we first investigated the interconversion between singlets and triplets in the charge-Transfer (CT) fluorescent OLED. Then we used MEL to study the generation paths of the excited states of the dopant in dye-doped fluorescent OLEDs: energy transfer and charge trapping.