Polarization properties of polymer graded-index rods

Abstract

Rubrene was doped into the hole transport layer of an organic thin film electroluminescent (OTFEL) device with a double-layered structure. It was found that the dopant has a profound influence on the EL characteristics-it changed the region of light emission, increased the luminescence efficiency by more than 50% and improved the device stability tenfold. The reasons for these effects are discussed based on injection theory and the energy level diagram of the device.