Synthesis and Characterization of Novel Triarylamine Derivatives with Dimethylamino Substituents for Application in Optoelectronic Devices

Two novel triphenylamine-based derivatives with dimethylamino substituents, N, N ′-bis(4-dimethylaminophenyl)- N, N ′-bis(4-methoxyphenyl)-1,4-phenylenediamine ( NTPPA ) and N, N ′-bis(4-dimethylaminophenyl)- N, N ′-bis(4-methoxyphenyl)-1,1′-biphenyl-4,4′-diamine ( NTPB ), were readily prepared for investigating the optical and electrochromic behaviors. These two obtained materials were introduced into electrochromic devices accompanied with heptyl viologen ( HV ), and the devices demonstrate a high average coloration efficiency of 287 cm 2 /C and electrochemical stability. Besides, NTPB / HV was further used to fabricate electrofluorochromic devices with a gel type electrolyte, and exhibit a controllable and high photoluminescence contrast ratio ( I off / I on ) of 32.12 from strong emission to truly dark by tuning the applied potential in addition to a short switching time of 4.9 s and high reversibility of 99% after 500 cycles.