MoO₃ has potential advantages in price and weight over more widely studied WO₃ for electrochromic devices, but it typically suffers from inferior electrochromic performance. Here, it is demonstrated that 2D MoO₃ nanosheets can be formed by intercalation and exfoliation of MoS₂ to form partially oxidized MoS_xO_y, followed by complete oxidation using a solution-phase nitric acid treatment. These fully oxidized MoO₃ nanosheets retain the 2D nature of exfoliated MoS₂ (70% of nanosheets are less than 9 nm thick), allowing for easier ionic diffusion through the film compared to bulk MoO₃ powder. When utilized as an electrochromic material, the device showed outstanding contrast (48.6% at 700 nm) and fast response time (11.3 s for bleaching, 9.8 s for coloration), which is far superior to that for standard powder MoO₃ and comparable to that for many nanostructures of WO₃. This shows the outstanding potential for these MoO₃ nanosheets in electrochromic applications.

中文翻译：

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MoS ₂的剥离和氧化合成二维MoO ₃纳米片，用于高对比度和快速响应时间的电致变色器件

MoO ₃在价格和重量方面均具有潜在优势，而在电致变色器件中，WOO _3的研究范围较广，但它通常具有劣质的电致变色性能。在此，证明了可以通过嵌入和剥离MoS ₂形成2D MoO ₃纳米片，形成部分氧化的MoS _x O _y，然后使用溶液相硝酸处理将其完全氧化。这些完全氧化的MoO ₃纳米片保留了脱落的MoS ₂的2D性质（70％的纳米片的厚度小于9 nm），与块状MoO ₃相比，离子易于通过薄膜扩散粉末。当用作电致变色材料时，该器件显示出出色的对比度（在700 nm下为48.6％）和快速的响应时间（漂白为11.3 s，着色为9.8 s），远远优于标准粉末MoO ₃并与之相当对于WO _3的许多纳米结构。这表明了这些MoO ₃纳米片在电致变色应用中的巨大潜力。