22 - Materials and physics of light-emitting electrochemical cells (LECs)

Abstract

After three decades of intensive research and development by academics and industries alike, organic photonic devices such as organic light-emitting diodes (OLEDs) have achieved great commercial success. Light-emitting electrochemical cells (LECs) are organic electroluminescent (EL) devices whose active layers contain not only electronic charges, but also mobile ions by design. Light emission in LECs occurs through in situ electrochemical doping (ECD) of the light emitter and the subsequent formation of a forward-biased p-n or p-i-n junction in the interior of the cell. As solid-state devices, LECs exhibit attractive characteristics and can be produced by low-cost manufacturing techniques. This chapter first presents an overview of LECs and the LEC fundamental operation mechanism. This is followed by an introduction to the innovation in LEC material design. A new type of LEC that operates on bipolar electrochemistry is introduced as well. Finally, the prospect of LEC-based lighting and display applications is discussed.