Dual‐band electrochromic smart windows capable of the spectrally selective modulation of visible (VIS) light and near‐infrared (NIR) can regulate solar light and solar heat transmittance to reduce the building energy consumption. The development of these windows is however limited by the number of available dual‐band electrochromic materials. Here, plasmonic oxygen‐deficient TiO_2‐x nanocrystals (NCs) are discovered to be an effective single‐component dual‐band electrochromic material, and that oxygen‐vacancy creation is more effective than aliovalent substitutional doping to introduce dual‐band properties to TiO₂ NCs. Oxygen vacancies not only confer good near‐infrared (NIR)‐selective modulation, but also improve the Li⁺ diffusion in the TiO_2‐x host, circumventing the disadvantage of aliovalent substitutional doping with ion diffusion. Consequently optimized TiO_2‐x NC films are able to modulate the NIR and visible light transmittance independently and effectively in three distinct modes with high optical modulation (95.5% at 633 nm and 90.5% at 1200 nm), fast switching speed, high bistability, and long cycle life. An impressive dual‐band electrochromic performance is also demonstrated in prototype devices. The use of TiO_2‐x NCs enables the assembled windows to recycle a large fraction of energy consumed in the coloration process (“energy recycling”) to reduce the energy consumption in a round‐trip electrochromic operation.

中文翻译：

---

等离子缺氧的TiO2-x纳米晶体，用于具有高效能量回收的双频电致变色智能窗户。

能够对可见光（VIS）和近红外（NIR）进行光谱选择性调制的双波段电致变色智能窗户可以调节太阳光和太阳热能透射率，从而降低建筑能耗。但是，这些窗口的发展受到可用的双波段电致变色材料数量的限制。在这里，等离子缺氧的TiO _{2 x}纳米晶体（NCs）被发现是一种有效的单组分双带电致变色材料，并且氧空位的产生比异价取代掺杂对TiO引入双带特性更有效。_2个NC。氧空位不仅可以提供良好的近红外（NIR）选择性调制，还可以改善TiO中Li ^+的扩散_{2 x}主机，避免了离子扩散进行异价置换掺杂的缺点。因此，经过优化的TiO _{2 x x} NC膜能够以三种不同的模式独立有效地调制NIR和可见光透射率，具有高光学调制度（633 nm处95.5％和1200 nm处90.5％），快速切换速度，高双稳性，循环寿命长。原型设备还展示了令人印象深刻的双频电致变色性能。TiO _{2 x x} NC的使用使组装的窗户可以回收着色过程中消耗的大部分能量（“能量回收”），以减少往返电致变色操作中的能量消耗。