VO₂ nanoparticle–based thermochromic films have shown great promise for applications in smart windows because of their relatively high luminous transmittance and solar modulation ability. To improve the lifetime of VO₂ nanoparticles, environmentally stable oxide materials such as TiO₂, SiO₂, and ZnO have been utilized as protecting shells. However, the shell material changes the optical performance of the thermochromic films because of the variation of the dielectric environment of the VO₂ nanoparticles. In this work, the effective medium theory is coupled with the transfer matrix method to study the influence of the optical constants of the shell materials and the shell thickness on the luminous transmittance and solar modulation ability of the VO₂ core–shell nanoparticle–based thermochromic films. The calculation results showed that it is challenging to simultaneously improve both the luminous transmittance and the solar modulation ability of core–shell structures. With the refractive index of the shell material being between 1.6 and 2.3 (e.g. ZnO and Cr₂O₃), there exists an optimal shell thickness to obtain the maximum solar modulation ability. The results reported in this study can be exploited to guide the design and development of high-performance VO₂ core–shell nanoparticle–based thermochromic smart window films.

基于VO ₂纳米粒子的热致变色膜因其相对较高的透光率和太阳光调制能力而显示出了在智能窗户中的应用前景。为了提高VO ₂纳米颗粒的寿命，已将环境稳定的氧化物材料（如TiO ₂，SiO ₂和ZnO）用作保护壳。然而，由于VO ₂的介电环境的变化，壳材料改变了热致变色膜的光学性能。纳米粒子。在这项工作中，有效介质理论与传递矩阵方法相结合，研究了壳材料的光学常数和壳厚度对基于VO ₂核-壳纳米粒子的热致变色材料的透光率和太阳调制能力的影响电影。计算结果表明，同时提高核壳结构的透光率和太阳调制能力具有挑战性。外壳材料的折射率在1.6和2.3之间（例如ZnO和Cr ₂ O ₃），则存在最佳的外壳厚度以获得最大的太阳调制能力。本研究报告的结果可用于指导高性能VO ₂核壳纳米粒子热致变色智能窗膜的设计和开发。