Fluorescence switching of triarylamine-based polyamides with pendant pyrene units and its application in electrochromic smart displays.

• Polyamides show solvochromic effects and large stokes shift. • Polyamides have specific fluorescent response to TNP and HCl. • Polyamides have excellent electrochromic and electrofluorescent properties. • The constructed electrochromic devices can display multiple colors. The pyrene group was directly connected to the triarylamine (TAA) unit through a benzene bridge via the Suzuki reaction to successfully prepare the diamine monomer. A series of new polyamides (PAs) based on TAA units were prepared by polycondensation. The PAs exhibited good solution processability and high thermal stability with the char yield in excess of 53 % at 800 °C in air atmosphere. In solvents with different polarities, these PAs showed solvatochromic effect and large stokes shift. Strongly photoluminescent PAs have a sensitive stimulus response to explosive and hazardous gas, and its fluorescence is easily turned off by the addition of trinitrophenol (TNP) and hydrogen chloride (HCl). And achieve fluorescence switching between exposure to HCl and ammonia (NH 3) gas. The PAs exhibited a reversible color response in the electrochemical oxidation process, with no significant degradation in current and transmittance after 200 cycles. The sandwich structure multicolor electrochromic device can achieve electrochromic performance applied by different voltages. [Display omitted] [ABSTRACT FROM AUTHOR]