Dual-band electrochromic smart windows with independent control of the transmittance of near-infrared (NIR) and visible (VIS) light can contribute significantly to the reduction of building energy consumption. Cost and inadequate electrochromic performance are the current technical challenges. We present here a dual-band electrochromic smart window design based on the intercalation/de-intercalation of Al³⁺ cations to replace the common use of monovalent cations in electrochromic applications. The Al³⁺ intercalation/de-intercalation-enabled electrochromic smart window delivers not only efficient and independent control of NIR and VIS light transmittance, but also impressive electrochromic performance – a high optical modulation of the full solar spectrum (93.2%, 91.7%, 88.5%, and 86.8% at 633, 800, 1200, and 1600 nm, respectively), high coloration efficiencies (254 and 121 cm² C⁻¹ at 1200 and 633 nm, respectively), fast switching times (8/5 s and 16/13 s at 1200 and 633 nm, respectively, for coloration/bleaching), and high bistability and cyclability (a 5.5% capacity loss after 2000 cycles). The good electrochromic performance can be attributed to the effective diffusion of Al³⁺ in the electrochromic material (as good as that of Li⁺); and a shallow intercalation/de-intercalation depth enabled by the ability of Al³⁺ to support three-electron redox reactions. The performance of Al³⁺ intercalation/de-intercalation-enabled dual-band electrochromism was also verified in laboratory prototype devices to confirm its suitability for dual-band smart windows.

中文翻译：

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具有Al ³⁺嵌入/去嵌入功能的双波段电致变色智能窗户，具有高光学调制，快速响应和长循环寿命†

具有对近红外（NIR）和可见（VIS）光的透射率的独立控制的双波段电致变色智能窗户可以显着降低建筑能耗。成本和不足的电致变色性能是当前的技术挑战。我们在此介绍一种基于Al ³⁺阳离子的嵌入/去嵌入的双频电致变色智能窗口设计，以取代单价阳离子在电致变色应用中的普遍使用。铝³⁺启用嵌入/解嵌入的电致变色智能窗口不仅可以有效且独立地控制NIR和VIS光透射率，而且还具有令人印象深刻的电致变色性能–可以对整个太阳光谱进行高光调制（93.2％，91.7％，88.5％和在633、800、1200和1600 nm处分别为86.8％），高着色效率（在1200和633 nm处分别为254和121 cm ² C ^-1），快速切换时间（8/5 s和16/13 s）分别在1200和633 nm处进行着色/漂白，并具有较高的双稳性和可循环性（2000次循环后容量损失5.5％）。良好的电致变色性能可归因于Al ³⁺在电致变色材料中的有效扩散（与Li ^{+一样）。}）; Al ³⁺能够支持三电子氧化还原反应，从而实现了较浅的插层/去插层深度。还在实验室原型设备中验证了支持Al ³⁺嵌入/去嵌入的双波段电致变色的性能，以确认其适用于双波段智能窗户。