In recent years, smart windows have increasingly focused on adjusting optical transmissive properties and providing efficient solutions for energy-saving buildings and vehicles. Electrochromic smart windows are considered a viable option for green buildings. However, conventional electrochromic devices require external voltage for operation, resulting in additional energy consumption. Furthermore, they cannot achieve zero transmission across the entire visible spectrum in the colored state, failing to provide high privacy protection. In this study, we present a self-powered electrochromic and thermochromic dual-responsive smart window that functions as a self-rechargeable battery and can achieve a highly private state across the entire visible range. We utilized the thermally stimulated phase transition behavior of hydroxypropyl methylcellulose to develop a thermochromic hydrogel for use in the electrolyte of electrochromic devices without compromising their electrochromic performance. This approach can be universally applied to electrochromic devices, and the phase transition temperature can be easily adjusted by varying the cationic species. In addition to its ion-conductive function, the electrolyte also exhibits thermochromic properties, enabling electrochromic devices to achieve four distinct states: a highly transparent (bleached) state, a milky white state (thermochromic), a blue state (electrochromic), and a fully nontransparent state (the dual-color private state). Notably, the electrochromic state can self-recover, regaining its transparent appearance simply by disconnecting the Zn and ITO electrodes. This recovery occurs due to the spontaneous oxidation of W⁵⁺ to W⁶⁺ facilitated by dissolved oxygen in the electrolyte. Consequently, the device we present is bifunctional, serving both as a self-powered electrochromic window and a thermochromic window. This innovative chromatic engineering significantly expands the industrial market for electrochromic smart window applications, catering to both public and private contexts, and offers enhanced flexibility in the design of building façades, paving the way for further industrial applications.

中文翻译：

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一种具有增强隐私保护能力的双功能自供电电致变色和热致变色智能窗


近年来，智能窗户越来越注重调整光学透射特性，为节能建筑和车辆提供高效的解决方案。电致变色智能窗被认为是绿色建筑的可行选择。然而，传统的电致变色器件需要外部电压才能运行，从而导致额外的能耗。此外，它们无法在有色状态下实现整个可见光谱的零传输，无法提供高度的隐私保护。在这项研究中，我们提出了一种自供电的电致变色和热致变色双响应智能窗口，它起到自充电电池的作用，可以在整个可见光范围内实现高度私密的状态。我们利用羟丙基甲基纤维素的热刺激相变行为开发了一种热致变色水凝胶，用于电致变色器件的电解质，而不会影响其电致变色性能。这种方法可以普遍应用于电致变色器件，并且可以通过改变阳离子种类来轻松调节相变温度。除了其离子导电功能外，电解质还表现出热致变色特性，使电致变色器件能够达到四种不同的状态：高度透明（漂白）状态、乳白色状态（热致变色）、蓝色状态（电致变色）和完全不透明状态（双色私有状态）。值得注意的是，电致变色态可以自我恢复，只需断开 Zn 和 ITO 电极即可恢复其透明外观。这种恢复是由于电解质中的溶解氧促进了 W⁵⁺ 自 发氧化为 W⁶⁺。 因此，我们提出的器件是双功能的，既可以用作自供电电致变色窗口，也可以用作热致变色窗口。这种创新的彩色工程显着扩展了电致变色智能窗户应用的工业市场，满足了公共和私人环境的需求，并为建筑立面的设计提供了更大的灵活性，为进一步的工业应用铺平了道路。