Multifunctional polyphosphazene grafted with triphenylamine and aminostilbene chromophore for electrochromic and sensor application

In this paper, a sequence of polyphosphazenes (PPZs) as electrochromic (EC) and sensor materials have been designed and synthesized by introducing chromophores, (4-(diphenyl amino)phenyl) methanol (CH1) for PPZ1, 3-(4-(dimethyl amino) phenyl)-2-(4hydroxyphenyl) acrylonitrile (CH2) for PPZ2, and CH1 and CH2 for PPZ3 into the main chain. In terms of EC performance, PPZ1 shows the best EC performance among the three PPZs which can achieve 60 % optical contrast at 690 nm with good cyclic stability within 1000 s and fast switching response time (t_color/t_bleach = 1.2 s/0.6 s). Compared to PPZ1, the oxidation potential of PPZ3 is reduced compared to PPZ1. PPZ2 and PPZ3 as sensors are more sensitive for the detection of 2,4,6-trinitrophenol (TNP) and trifluoroacetic acid (TFA) compared to PPZ1. What's more, PPZs can be used in memory devices with non-volatile flash memory performance and switching current ratios of 10³:10^2.4:1, 10^4.7:10^1.3:1 and 10^3.5.:10^0.6:1 respectively. Therefore, PPZs have the promising prospect in optoelectronic field.