Visible and Near‐Infrared Dynamic Electrochromic Modulation With the Plasmon‐Enhanced Two‐Dimensional Ordered Macroporous Au/PProDot‐Me₂ Thin Film

Abstract Localized surface plasmon resonance (LSPR) is attractive to fabricate visible (VIS) and near‐infrared (NIR) dual‐band electrochromic materials. However, the introduction of the LSPR effect in the available dual‐band electrochromic materials can only be manifested to the spectral enhancement in the NIR region, and difficult issues of electrochromic materials such as low coloration efficiency and unsatisfactory long‐term cycling durability still remain. Here, a dual‐band electrochromic thin film consisting of a 2D ordered macroporous (2DOM) Au LSPR layer and a poly(3,4‐(2,2‐dimethylpropylenedioxy)thiophene) (PProDot‐Me₂) electrochromic layer is presented, where LSPR and electrochromism interact in a complementary fashion. The 2DOM Au exhibits LSPR effect at wavelengths of 550 and 1700 nm, leading to a unique electrochromic performance improvement of the film in both of the VIS and NIR spectral regions. Large optical modulation, rapid switching speed, high coloration efficiency, and long‐term durability are achieved due to the collective effect of the near‐field enhancement of the 2DOM Au and the reduced bandgap of PProDot‐Me₂. These advantages can be well retained in the dual‐band electrochromic device using the 2DOM Au/PProDot‐Me₂ films as the electrochromic layers. This work provides new ideas for designing LSPR‐based devices, especially dual‐band electrochromic materials and devices, both experimentally and theoretically.