Oriented Surface-Anchored Metal–Organic Frameworks (SurMOFs) as Electrochromic Thin Films

摘要

Novel electrochromic hybrid thin films are synthesized following a liquidphaseepitaxy in a layer-by-layer fashion, yielding highly oriented surfaceanchoredmetal–organic frameworks (SurMOFs). The initial orange colorof this {Zn_2(PDICl_4)_2} crystalline thin films is reversibly switched by electrochemicalreduction. In a lithium-based electrolyte, a dark blue color isobtained in few seconds with a color efficiency of 104.8 cm~2 C~(?1) (λ = 645 nm).Interestingly, the color of the reduced state is easily modulated by changingthe electrolyte composition. Clearly, two different mechanisms are implicatedand the reduced species responsible of the color are identified. Takingadvantage of this unusual property, electrochromic devices with a novel configurationare designed leading to an original prototype capable of reversiblyswitching from a single initial orange color to two different colors simultaneously,namely dark blue and cyan.