Charge carrier mobility in organic materials measurement with time-of-flight technique

Carrier mobility has an instant demand for understanding the operation mechanism in organic electroluminescent (EL) materials. Under the same electrical field, higher device current can be induced as utilizing higher carrier mobility material. In this report, we have measured the mobility of MA103 (Hole Injection Layer, HIL), MA203 (Hole Transport Layer, HTL), NPB (HTL) and Bebq₂ (Electron Transport Layer, ETL) with time-of-flight (TOF) technique. The TOF sample is a single-layer OLED (organic light emitting display), and the active area is 1×1 cm². Experimental results show that hole mobilities of MA103, MA203, and NPB are about one order magnitude higher than the electron mobility of Bebq². Finally, the time-of-flight system has successfully constructed by RiTdisplay Corp., and it can accurately measure the mobility of organic materials.