Organic electroluminescent device based on balanced carriers injection and transportation
摘要: The electronic structure of PDDP, T-3-OXD and Alq in forms of HOMO, LUMO and E-g is characterized by using spectroscopy and electrochemical measurement, and the carrier mobility of them is measured by a time of flight (TOF) technique. Based on these knowledge, single-layer and double-layer EL devices are fabricated. The experimental results indicate that the EL performances of the device depend not only on the energy matching among the emitting layer, carrier transporting layer and the electrode, but also on the mobility and the thickness of emitting and transporting layer. in other words, four orders of magnitude an increase of the EL efficiency can be achieved by choosing the electron transporting material with suitable electronic structure and carrier mobility, the electrode with relatively low work function and a proper thickness of the emitting and transporting layer.