Applications of polymer coatings consisting of 9,9′-(4,4′-sulfonylbis (4,1-phenylene))biscarbazole and thiophene derivatives in electrochromic devices

A carbazole derivative (9,9 '-(4,4 '-sulfonylbis(4,1-phenylene))biscarbazole (SpDc)) was synthesized; subse-quently, P(SpDc), P(SpDc-co-TP), P(SpDc-co-MTP), P(SpDc-co-PTP), and P(SpDc-co-HTP) films were electro-chemically coated on ITO/glass substrates. Electrochromic characterizations show that the P(SpDc) film is pale ochre, dark khaki, moss green, and dark olive green at 0.0, 0.8, 1.0, and 1.1 V, respectively. The square wave potential step absorptiometry of the polymeric coatings shows that the P(SpDc-co-PTP) film exhibits a high transmittance change (AT = 52.8%) and a moderate coloration efficiency (eta = 120.8 cm2 C-1). Furthermore, dual-layer electrochromic devices (ECDs) were fabricated using P(SpDc), P(SpDc-co-TP), P(SpDc-co-MTP), P (SpDc-co-PTP), and P(SpDc-co-HTP) as anodic coatings and PProDOT-Bz2 as the cathodic coating. P(SpDc-co- TP)/PProDOT-Bz2 ECD exhibited multicolored electrochromism, a high AT (50.9% at 635 nm), a high eta (820.5 cm2 C-1 at 635 nm), and a fast switching time (less than 0.1 s). Given the adequate electrochromic performance of the organic coatings, it can be inferred that these coatings could be used in promising organic ECD applications.

Automated summary

A carbazole derivative was synthesized, and various polymer films were electrochemically coated on ITO/glass substrates. The electrochromic characterization showed that the films exhibited different colors at different voltages. The dual-layer electrochromic devices demonstrated multicolored electrochromism, high transmittance change, high coloration efficiency, and fast switching time, suggesting potential applications in organic electrochromic devices.