【作者】 刘志强；

【导师】 蔡国发；

【作者基本信息】 河南大学 ， 光电信息工程（专业学位）， 2025， 硕士

【摘要】 电致变色器件（Electrochromic devices,ECDs）是指在较低电压驱动下使自身光学属性发生可逆变化的一种装置,在显示技术、智能窗户、动态伪装等领域具有重要的应用前景。通常,电致变色层是电致变色器件的核心部件,直接决定器件的性能。电致变色层的微观结构对电致变色性能起着重要作用,然而其极易受到制造技术的影响。随着人们越来越关注将电致变色集成到各个技术领域,电致变色层不仅需要满足均匀性和良好的光调制性,还需要满足额外的要求,例如在显示领域,电致变色层需要具有丰富的色彩、定制化的图案和足够大的面积。目前,传统方式（例如,水热、气相沉积、磁控溅射等）制备电致变色薄膜的尺寸受限于反应室的容量,难以实现大尺寸的电致变色薄膜的构筑。而且过大的生产设施往往价格较为昂贵,生产标准较为严格,这无疑增加了制膜的成本。喷涂技术和数字印刷技术虽然可以在温和条件下制造大面积和图案化的电致变色薄膜。但用于印刷的油墨通常需要高沸点溶剂和表面活性剂,这些溶剂和表面活性剂是非导电的,可能会阻碍电子传输。因此,开发一种简单、经济高效的技术和无粘合剂的制备用于不同应用场景的电致变色薄膜非常重要。五氧化二钒（V₂O₅）是一种阴阳极多变色材料,具有良好的应用前景,本论文针对V₂O₅电致变色材料难以大面积成膜的问题提出了两种策略,成功制备了具有高光学性能的和大尺寸图案化V₂O₅薄膜,并进一步构建了具有优异性能的多彩ECDs。研究内容主要包含以下两部分:（1）液/液界面自组装（Liquid/liquid interface self-assembly,LLIA）V₂O₅薄膜:我们提出了一种液/液界面自组装策略以构建大面积（600 cm²）V₂O₅电致变色薄膜,使用乙醇分子对V₂O₅纳米带进行表面修饰,获得两亲性的V₂O₅纳米带。利用有机溶剂和水之间的强极性差驱动两亲性的V₂O₅纳米带均匀地铺展在液/液界面上并连接成高质量的薄膜。因此,组装的V₂O₅电致变色薄膜表现出皱纹的微观形貌和高度均匀性,厚度可控,同时可以进一步通过改变有机溶剂的种类调控极性差来控制薄膜的质量,优化纳米带之间的连接性。厚度仅78 nm的V₂O₅薄膜在760 nm处的光学调制即可高达53%,并且通过调整薄膜厚度,光学调制最高可达70%。进一步将LLIA技术和掩模技术相结合制备了一系列图案化薄膜和大面积（100 cm²）多彩ECDs,展示了LLIA V₂O₅薄膜在防伪显示和信息加密方面的应用前景。为验证LLIA策略的普适性,采用同样的方法制备了LLIA WO₃电致变色薄膜,并构建了大面积（100 cm²）图案化的ECDs,同样展示出优异的电致变色性能。这种条件温和,工艺简易且经济高效的界面自组装策略,在实现大面积过渡金属氧化物（TMOs）薄膜的制备具有较大潜力,为电致变色器件的实际应用提供了新的思路。（2）二维材料辅助原位生长（Two-dimensional material-assisted in-situ growth,TAIG）V₂O₅薄膜:我们采用二维材料辅助原位生长的方式制备V₂O₅薄膜。利用V₂C MXene在水氧环境下易发生氧化水解的特点,以其为模板在60℃下原位生长了具有优异电致变色性能的大尺寸V₂O₅薄膜。通过调节生长时间和温度,探究其成膜机理并优化电致变色性能,成功制备出最高可达90%的TAIG V₂O₅薄膜。其高性能源于TAIG方法制备的V₂O₅薄膜成功的引入了氧空位缺陷,提升了变色过程中的电子传输效率。此外,这种原位生长方式提升了薄膜与基底的结合力,赋予薄膜优异的响应时间（着色/褪色时间为7.2/2.9 s）和良好的循环稳定性,在2000次循环后薄膜保持光学调制范围初始值的82%。这种制备方法操作简单且条件温和,成功制备了大尺寸（100 cm²）的V₂O₅薄膜和高分辨率图案化多彩ECDs,展示了其在多彩显示领域的潜力,为V₂O₅在储能、柔性电子、催化等领域的应用提供了新的思路。更多还原

【Abstract】 Electrochromic devices can switch their optical properties reversibly by electrochemical reactions upon applied alternately low potentials,showing great promising applications in information displays,energy efficient smart windows,camouflage etc.Typically,the electrochromic layer is the core component of electrochromic devices and determine the device performance directly.In particular,the microstructure of electrochromic layer plays an important role in the electrochromic performance,which is extremely susceptible to layer fabrication technology.With the growing interest in integrating electrochromism into various technology fields,the electrochromic layer not only needs to satisfy uniformity and good optical modulation,but also needs to meet additional requirements,such as in the display field,electrochromic layers need to have rich colors,customizable patterns and large size.Currently,the dimensions of electrochromic films produced through conventional technologies（e.g.,hydrothermal,vapor deposition,magnetron sputtering,etc.）influenced by the capacity of the growth chamber.However,oversized production facilities are often more expensive and require stricter standards,which undoubtedly increase the costs of film production.Recently,coating technologies and digital printing technologies were introduced to fabricate large-area and patterned electrochromic film under the mild conditions.However,the ink for printing usually requires high boiling point solvents and surfactants,which are non-conductive and could obstruct the electronic transfer.Hence,the development of a simple,cost-effective technology and binder free for the preparation of electrochromic films for different application scenarios is of importance.Vanadium oxide（V₂O₅）is a cathode and anode multicolor-changing material with good development prospects.We propose two strategies on the difficulty of large-area film formation of V₂O₅ electrochromic materials.We successfully prepared and large-size patterned V₂O₅ films with high optical properties and further constructed multicolorful ECDs with excellent performances.The research mainly consists of the following two parts:（1）Liquid/liquid interface self-assembly（LLIA）V₂O₅ thin films:We propose a liquid/liquid interfacial self-assembly strategy to construct large-area（600 cm²）V₂O₅electrochromic films.Surface modification of V₂O₅ nanoribbons using ethanol molecules to obtain amphiphilic V₂O_5.The strong polarity difference between organic solvent and water was utilized to drive the amphiphilic V₂O₅ nanoribbons to spread uniformly on the liquid/liquid interface and connect into a high-quality film.As a result,the assembled V₂O₅ electrochromic films exhibit wrinkled microscopic morphology and high uniformity with controllable thickness,while the quality of the films can be further controlled by modulating the polarity difference by changing the type of organic solvent to optimize the connectivity between the nanoribbons.The optical modulation of the V₂O₅ film with a thickness of only 78 nm can be as high as 53%at 760 nm,and up to 70%by adjusting the thickness of the film.A series of patterned films and large-area（100 cm²）colorful ECDs were further prepared by combining the LLIA technology with mask technology,demonstrating the application of LLIA V₂O₅ films in anti-counterfeit display and information encryption.To verify the universality of the LLIA strategy,LLIA WO₃ electrochromic films were prepared by the same method,and large-area（100 cm²）patterned ECDs were constructed,which also demonstrated excellent electrochromic performance.LLIA strategy with mild conditions and,a simple and cost-effective process has great potential in realizing the preparation of large-area transition metal oxides（TMOs）thin films,which provides a new idea for the practical application of electrochromic devices.（2）Two-dimensional material assisted in-situ growth（TAIG）V₂O₅film:We used two-dimensional material-assisted in situ growth to prepare V₂O₅ thin films.Using V₂C MXene,which is prone to oxidative hydrolysis under water-oxygen environment,we used it as a template for in situ growth of large-size V₂O₅ films with excellent electrochromic properties at60°C.The growth time and temperature were adjusted to investigate the film formation mechanism and optimize the electrochromic properties.By adjusting the growth time and temperature,exploring the forming mechanism,and optimizing the electrochromic properties,TAIG V₂O₅ films of up to 90%were successfully prepared.The high-performance stems from the successful introduction of oxygen vacancy defects in the V₂O₅ films prepared by the TAIG method,which enhances the electron transport efficiency during the electrochromic process.In addition,this in-situ growth method improves the bonding of the film to the substrate,giving the film an excellent response time（coloring/fading time of 7.2/2.9 s）and good cycling stability,with the film maintaining 82%of the initial value of the optical modulation range after 2,000cycles.With simple operation and mild conditions,we have successfully prepared large-sized（100 cm²）V₂O₅ films and high-resolution patterned multicolorful ECDs,Demonstrating their potential in the field of colorful displays.Providing new ideas for the application of V₂O₅ in the fields of energy storage,flexible electronics,catalysis,and so on.更多还原