Synthesis And Electrochromic Properties Of Triarylamine Polymers

Triphenylamin polymers are widely used in light-emitting diodes, solar cells, electrochromic devices, and memory devices. Triarylamine polymers as electrochromic material is based on the lone pair of electrons in N atom which is very easily oxidized to form a radical cation when a voltage is applied to produce a change in color. Triarylamine polymers revealed fast switching ability, excellent reversible electrochromic stability and high coloration efficiency.Triphenylamine polymers(P1 and P2) were synthesized with reaction of 4-dimethylaminoaniline and aromatic dibromide by Buchwald-Hartwig coupling method. The polymers were characterized by FT-IR and 1H NMR. Thermal analysis shows that P1 and P2 have high thermal stability and decomposition temperature of 455 and 450 oC in the 5% weight loss, respectively. Based on the lone pair of electrons in N atom, electrochemistry and electrochromic character of P1 and P2 films were investigated in p-Toluenesulfonic Acid/CH3 CN electrolyte. P1 and P2 films show excellent reversible electrochromic stability and fast switching ability, which revealed switching time of 2.2s for coloring process and 2.4s for bleaching. Memory device constructed of ITO//P1- p-Toluenesulfonic Acid//Al showed that P1 realed WORM characteristic and switch current ratio(ON/OFF) of 103. Thus, these characteristics suggest that these novel triphenylamine polymers have great potential for practical applications in electrochromic and memory field.