Electrosynthesis of electrochromic polymers based on bis-(4-(N-carbazolyl)phenyl)-phenylphosphine oxide and 3,4-propylenedioxythiophene derivatives and studies of their applications in high contrast dual type electrochromic devices

Five phenylphosphine oxide-containing polymers (PBCPO (poly(bis-(4-(N-carbazolyl)phenyl)-phenylphosphine oxide)), P(BCPO-co-ProD-Me2), P(BCPO-co-ProD-Et2), P(BCPO-co-ProD-Bz2), and P(BCPO-co-ProD)) are electrodeposited on indium tin oxide (ITO) coated glass slide and their electrochromic performances are characterized. The optical band gap of PBCPO is 3.14 eV. P(BCPO-co-ProD-Bz2) attains a high transmittance change (ΔT = 55% at 740 nm) and shows multicolored electrochromism from light tan (0.0 V), grayish-green (0.4 V), greenish-gray (1.1 V) to deep gray (1.2 V). Electrochromic devices (ECDs) containing phenylphosphine oxide-based polycarbazoles and poly(3,4-ethylenedioxythiophene) (PEDOT) as active electrode layers are constructed. PBCPO/PEDOT ECD displays light gray, gray, and greenish-gray at 0.0, 0.8, and 1.9 V, respectively. P(BCPO-co-ProD-Bz2)/PEDOT ECD displays a high optical contrast (ΔT = 42.5% at 630 nm) and P(BCPO-co-ProD)/PEDOT ECD shows a high coloration efficiency (η = 454.1 cm2•C−1 at 630 nm). In addition, P(BCPO-co-ProD derivatives)/PEDOT ECDs have adequate optical memories and long-term redox cyclic stability.