Electro-fluorescence Switching of Bis-imidazolium Ionic Liquids

Abstract

Room-temperature ionic liquids (RTILs) containing bis-imidazolium salts were explored to control their optical properties of them in an organic device. The neat bis-imidazolium salts showed ionic conductivity of 3.5 x 10(-4) S/cm at room-temperature and the electrochemical window was exhibited within +/- 2.5 V in a two electrode cell. The bis-imidazolium salts were transparent yellow and showed fluorescence upon excitation with light in the range of 360 to 500 nm. A two electrode organic ionic liquid cell was fabricated using a mixture of PEO(200)Blm-TFSI and electroactive molecules to control the emission property of the ionic liquid by electrochemical methods. The first example of the ionic liquid containing electro-fluorescence switch was explored with an electroactive benzyl viologen (BzV) blend of bis-imidazolium ionic liquid.