Tin-doped indium oxide (ITO) films are often used as transparent electrodes for optoelectronic applications such as electrochromic devices (ECDs) and solar cells. Preparing ITO films below intermediate temperatures (≤ 350 °C) has become a challenge that must be solved to expand their range of applications (such as all-solid-state ECDs based on phosphate proton conductors and flexible optoelectronic devices). This work aims to develop a practical technique for preparing ITO films at intermediate temperatures. The performances of ITO films prepared by sol-gel and magnetron sputtering methods at these temperatures were compared. The scattering effect of the organic residues in the film, such as the C–H and CC groups, hinders the substitution of Sn4 + with In3+, the grain growth and the carrier migration, leading to poor carrier concentration and mobility. These factors hindered the preparation of highly transparent and conductive ITO films obtained by sol-gel method. By combining room temperature magnetron sputtering with heat treatment under an O2 followed by a reducing atmosphere below 350 °C, a carbon-free ITO film with an average visible light transmittance of 87.0 % (with substrate) and a resistivity of 2.3 × 10−4 Ω·cm was obtained. Further experiments investigated the feasibility of applying the obtained film in all-solid-state ECDs with ITO/tungsten oxide/phosphate proton conductor/nickel oxide/ITO structure. This ECD exhibits good electrochromic capabilities, particularly demonstrated by a bleached state transmittance of up tp 76 % at 650 nm, which endows it with outstanding transparency characteristics. This work not only clarifies the limitations and causes of the intermediate temperatures preparation of ITO films by sol-gel method, offering a theoretical reference for the selection of ITO film preparation technologies, but also lays a foundation for the development of novel substrate-free all-solid-state ECDs.

中文翻译：

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锡掺杂氧化铟薄膜的制备及其在基于磷酸盐质子导体的全固态电致变色器件中的应用


掺锡氧化铟 （ITO） 薄膜通常用作光电应用的透明电极，例如电致变色器件 （ECD） 和太阳能电池。在中等温度 （≤ 350 °C） 以下制备 ITO 薄膜已成为一项挑战，必须解决以扩大其应用范围（例如基于磷酸盐质子导体的全固态 ECD 和柔性光电器件）。这项工作旨在开发一种在中等温度下制备 ITO 薄膜的实用技术。比较了溶胶-凝胶和磁控溅射方法制备的 ITO 薄膜在这些温度下的性能。薄膜中有机残基（如 C-H 和 CC 基团）的散射效应阻碍了 Sn4 + 被 In3+ 取代、晶粒生长和载流子迁移，导致载流子浓度和迁移率差。这些因素阻碍了溶胶-凝胶法制备高透明和导电的ITO薄膜。通过将室温磁控溅射与在 O2 下进行热处理，然后在 350 °C 以下的还原气氛下进行处理，获得了平均可见光透射率为 87.0 %（含衬底）和 2.3 × 10−4 Ω·cm 电阻率的无碳 ITO 薄膜。进一步的实验探讨了将获得的薄膜应用于具有 ITO/氧化钨/磷酸盐质子导体/氧化镍/ITO 结构的全固态 ECD 的可行性。这种 ECD 表现出良好的电致变色能力，特别是在 650 nm 处高达 tp 76 % 的漂白态透射率证明了这一点，这使其具有出色的透明特性。 这项工作不仅阐明了溶胶-凝胶法中间温度制备 ITO 薄膜的局限性和原因，为 ITO 薄膜制备技术的选择提供了理论参考，也为开发新型无衬底全固态 ECD 奠定了基础。