Electrochemical Modulation of Emission and Coloration by Using Luminescent Lanthanide(III) Complex and Viologen Derivatives via Intermolecular Energy Transfer

Abstract

A dual-mode display device which can operate in both emissive and reflective modes, having advantages of both modes, is considerable promise as a next generation display. In this review, electrochemical switching systems, which enable simultaneous control of both emission and coloration, are reviewed in order to create the novel displaying materials. A luminescent europium(III) [Eu(III)] complexes, one of the important lanthanide (III) complexes, and electrochromic molecules of viologen derivatives were combined for appearance of the multi-functionality. The Eu(III) complex emission was controlled by the electrochromism of the viologen derivatives via an intermolecular energy transfer mechanism. When viologen derivatives were in a colorless state, a strong red emission was observed from the Eu(III) complex. On the other hand, the electrochemically colored viologen derivatives effectively quenched the red emission of the Eu(III) complex. However, these systems lacked quick response and high reversibility of the fluorescence modulations. Some of the researches for improving these disadvantage of primary study are described. Furthermore, numerical representations and multi-color representations with emissive and reflective modes were also achieved.