Chapter 3 Materials in Thin Film Electroluminescent Devices

Abstract

Publisher Summary This chapter focuses on electroluminescent (EL) devices and electrical energy that is converted to visible light by a nonthermal process. The EL devices can be divided into two classes: (1) light-emitting diodes (LEDs), where the light is generated by electron-hole pairs, and (2) high-energy EL devices, where the high-energy electrons excite the emitting centers (dopant ions) to give luminescence. The EL devices are grouped in different types depending on the form of phosphors, powder vs thin film, and of the driving voltage, AC vs DC. Two of these types— namely, AC thin film electroluminescent (ACTFEL) devices and AC-driven powder EL devices—are commercially available. The current state-of-the-art of materials needed in TFEL devices are highlighted in the chapter. This includes all materials—substrates, conductors, dielectrics, and phosphors. An ACTFEL device consists of a metal–insulator–semiconductor–insulator–metal (MISIM) structure deposited on a substrate which, in a traditional case, is a transparent glass.