Design,Synthesis Of Poly (Ionic Liquid) And Its Application In Electrochromic Luminescence Devices

Electrochromic luminescence is defined as reversible modulation of luminescent properties of photoelectric materials.To date,materials showing electrochromic luminescent properties have been used in various optoelectronic devices.Electrochromic luminescence device normally consists of host material(electrolyte)and guest material(electrochromic luminescent material).The polymeric ionic liqiud is the polymer containing both anions and cations in repeating units.They have been extensively studied and applied as electrolytes in many types of optoelectronic devices because of their advantages of high ionic conductivity,wide potential window,chemical and electrochemical stability,thermal stability,high mechanical strength and so on.Phosphorescent iridium(?)complexes which have excellent photophysical properties and rich excited state properties are ideal candidates for electrochromic luminescent material.These complexes can show highly sensitive optical properties toward surrounding microenvironment or external stimuli(such as p H value,vapor,electric field,temperature and mechanical force).The main contents of this thesis are focus on the design and synthesis of imidazole-based electrolytes and electrochromically luminescent iridium(?)complexes,and their application in electrochromic luminescence device:1.Design and synthesis of imidazole-based electrolytes and their application in electrochromic luminescence device.In this chapter,we have designed and synthesized small-molecule ionic liquids and polymeric ionic liquids with different counterions as electrolytes in electrochromic luminescence devices.The polymer based electrolyte showed a lower critical voltage(2.5 V)compared to the liquid solvent,demonstrating high performance of electrochromic luminescence device.The situ spectrum of devices showed that the intensity of the maximum emission peak increases with the increase of the voltage,accompanying with a blue shift(28 nm).2.Design and synthesis of smart iridium(?)complexes and their application in electrochromic luminescence device.In this chapter,iridium(?)complexes Ir1 and Ir2 containing two hydrogen bond receptors were designed and synthesized.The absorption spectra of Ir1 and Ir2 are similar in CH3 CN solution,demonstrating the negligible effect of counterions on optical absorption of complex.In contrast,the emission peaks of these complexes in CH3 CN solution displayed a significant red shift from 493 nm to 590 nm.In addition,Ir2 showed electrochromic luminescence properties.Subsequently,a flexible electrochromic luminescence device was successfully constructed with the mixture of Ir2 and bisimidazole polymer(1-methyl-3-(trifluoromethanesulfonyl)imide)(P6).The emission color near the cathode of the device changed from the original orange to green under the electric field.The fabricated electrochromic luminescence device exhibits high performance,such as low operation voltage,fast response time,as well as flexible display.