Combinatorial exploration of thermochromic thin films in V-M1-M2-O systems

该项目旨在探索V-M1-M2-O体系（M1， M2：例如W， Mg, Er, Li）中基于vo2的热致变色薄膜，以用于未来在智能窗户中的应用。待开发的薄膜在室温下可逆相变后将显示出高透光率（Tlum）和太阳辐照调制（ΔTsol）。第三元素的加入可以降低VO2基相的转变温度（Tc），提高其热致变色性能（Tlum和ΔTsol），如W可以有效降低VO2（68℃）的Tc，但Tlum和ΔTsol变质；碱金属和稀土金属提高了tum，但没有显著降低Tc。因此，需要探索一个多维搜索空间，以确定满足所有必要要求的新的多材料。因此，为了获得更好的用于智能窗口的vo2基薄膜性能，首先，将研究具有M1未探索元素的V-M1-O体系，以寻找降低Tc和提高Tlum的元素。然后，将探索四元体系（V-M1-M2-O）：期望M1和M2对VO2的热致变色性能产生协同效应，以实现低Tc和高Tlum。这需要一个大的实验数据集，这将通过合成组合材料库及其高通量表征来完成。为了进一步增强Tlum，最好的系统将通过掠角沉积制成纳米多孔膜，并应用保护性抗反射涂层进一步优化Tlum。

This project addresses the exploration of VO2-based thermochromic thin films in V-M1-M2-O systems (M1, M2: e.g. W, Mg, Er, Li) for future application in smart windows. Films to be developed will show high luminous transmittance (Tlum) and solar irradiation modulation (ΔTsol) upon a reversible phase transformation around room temperature. Addition of third elements can decrease the transition temperature (Tc) and improve the thermochromic performance (Tlum and ΔTsol) of VO2-based phases: e.g. W can effectively decrease Tc of VO2 (68°C), but Tlum and ΔTsol are deteriorated; alkaline and rare-earth metals improve Tlum but do not lower substantially Tc. Therefore, a multidimensional search space needs to be explored in order to identify a new multinary material which fulfils all necessary requirements. Thus, to achieve better performance of VO2-based thin films for smart windows, first, V-M1-O systems with unexplored elements for M1 will be investigated in search for elements which reduce Tc and improve Tlum. Then, quaternary systems (V-M1-M2-O) will be explored: synergistic effects of M1 and M2 on the thermochromic properties of VO2 are expected, to achieve lower Tc and higher Tlum. This needs a large experimental dataset which will be accomplished by synthesis of combinatorial materials libraries and their high-throughput characterization. The best identified systems will additionally be fabricated as nanoporous films by glancing angle deposition in order to further enhance Tlum, and a protective antireflective coating will be applied to further optimize Tlum.