Fabrication of FTO/PNIPAm/FTO Electrical‐Thermal Dual‐Response Smart Window for Solar Radiation Management in the Full Temperature Range**

Abstract

Abstract Dual‐response smart window, which can respond to two external stimuli simultaneously or separately, has more solar adjustment modes and a wider range of solar radiation adjustment. In this paper, a double‐layer fluorine‐tin oxide (FTO) electrical‐thermal mold was presented, and poly(N‐isopropylacrylamide) (PNIPAm) hydrogel was encapsulated in the mold to form an electric‐thermal dual‐response smart window. The electrical response refers to the electrothermal conversion characteristics of the double‐layer FTO mold used to compensate for the insufficient thermochromic performance of the PNIPAm hydrogel when temperature is between 25 °C and 32 °C, rather than electrochromic properties. Finally, when the applied voltage reaches 5 V, the dual‐response smart window achieves a high solar modulation ability (Δ T sol ) of 26.51 %. In addition, it can be concluded that a 5 V of applied voltage is adequate for the dual‐response smart window (25 mm×25 mm×2.2 mm) to exhibit excellent Δ T sol and extremely fast response speed by the test of the electrothermal conversion performance, transparency change during the heating process, and UV‐Vis‐NIR transmittance spectra. Furthermore, the thermal management tests and cyclic stability tests indicate that the smart window has a potential energy saving effect and environmental tolerance. The prepared smart window enables PNIPAm hydrogel to manage solar radiation well in the entire ambient temperature range actively or passively.