Electrically and Thermally Controllable Visible-to-Near-Infrared Light Trapping Smart Window with Tunable Optical States

摘要

In this work, active viologen anchored on poly(2-isopropyl-2-oxazoline) (PiPO)segments spaced with triazole-bearing oxyethylene chain (POE_m-PiPOHPV)molecule is discovered to be an effective single-component dual-bandchromic material. Unlike most reported materials of this type, POE_m-PiPOHPVnot only is electrochromic but thermochromic as well, showing opticalswitching from clear to hazy at ≈55–59 ℃ as a result of phase transformationwhen triggered by heat attaining >60 optical contrast (ΔT) both in thevisible and near infrared (NIR) range. Likewise, >75 ΔT is achievedwhen switched from clear state to colored state at an applied potential(≈0.45–2.9 V). Each distinct mode of chromism uniquely and autonomouslymodulates visible and NIR light. Multiple color states-hazy, burgundy,brown, dark purple, and royal blue-are also displayed when the spacerlength is modified and when the counteranions undergo metathesis. A colorationspeed of 25 s resulting in purple color and a bleaching speed of 11 s areattained by PiPO with hepta-oxyethylene chain and hexafluorophosphateanion (POE_7-PiPO-HPV-PF_6) with a coloration efficiency of 295.0 cm~2 C~(?1) andcyclic stability of >200 cycles.