Gradient Variation Oxygen-Content Vanadium–Oxygen Composite Films with Enhanced Crystallinity and Excellent Durability for Smart Windows

Abstract

Vanadium dioxide (VO 2 )-based smart windows show excellent promise for energy-saving and have been extensively researched. However, for the glass industry-compatible magnetron sputtering process, VO 2 films are difficult to obtain and have homogeneous crystalline state, leaving them lacking the ideal solar modulation (ΔT sol ) and sensitivity (narrow hysteresis loop). More importantly, the instability of VO 2 hinders its commercialization. Multilayer structures have been repeatedly investigated to solve these problems. Unfortunately, the mediocre thermochromic properties as well as the complex and expensive manufacturing steps still hinder its commercialization. In this work, we prepared gradient variation oxygen-content vanadium−oxygen composite films (V 2 O 3 /VO 2 /V 2 O 5 , VO gv ) with enhanced crystallinity and excellent durability by one-step continuous sputtering. According to optical measurements, the ΔT sol of the VO gv films was significantly increased by 145% (from 6.85 to 16.80%) compared to VO 2 films, and the width of the hysteresis loop was reduced by 67% (from 19.34 to 6.36 °C), while the VO gv films exhibited a wider preparation window. The accelerated tests have shown that the film has an equivalent service life of approximately 20 years. We exploited the intrinsic similarity in properties of homologous compounds of vanadium oxide and simplified the preparation process, which is supposed to break the existing application bottlenecks and increase the commercializing possibility of VO 2 -based thermochromic smart windows.

An Interesting Functional Phase Change Material VO2: Response to Multivariate Control and Extensive Applications in Optics and Electronics

“…Vu et al [182] first formed a unique VO 2 nanorod embedded structure by introducing seeding to guide growth during the reaction sputtering process, and then formed a V 2 O 5 /VO 2 thermochromic composite film (as shown in the Figure 17 g), the presence of V 2 O 5 reduced the lattice mismatch of the amorphous surface of VO 2 crystal and blocked water oxygen, thereby greatly slowing down the oxidation process of VO 2 , and finally tested the life of the smart window was as high as 33 years. Similarly, Li et al [184] designed a V 2 O 3 /VO 2 /V 2 O 5 structure, which also uses the V 2 O 5 layer to hinder the oxidation of VO 2 , and the service life of the window can reach 20 years after accelerated experimental tests. In addition, the use of core-shell coating can greatly slow down the oxidation process of VO 2 and ensure the optical properties of the prepared thin film.…”

“…Similarly, Li et al. [ 184 ] designed a V 2 O 3 /VO 2 /V 2 O 5 structure, which also uses the V 2 O 5 layer to hinder the oxidation of VO 2 , and the service life of the window can reach 20 years after accelerated experimental tests. In addition, the use of core‐shell coating can greatly slow down the oxidation process of VO 2 and ensure the optical properties of the prepared thin film.…”

Bio‐Inspired, Scalable, and Tri‐Mode Stimuli‐Chromic Composite for Smart Window Multifunctionality

“…[ 5–7 ] Extensive research effort has been put into the development of functional intelligent layers, glazing, and structures, which are made of materials with active and dynamic light modulation characteristics. [ 8–11 ] Recent development of smart window technology can be mainly classified as electro‐, [ 12–16 ] thermo‐, [ 17–19 ] mechano‐, [ 20–22 ] photo‐, [ 23 ] and hydro‐/solvato‐chromism, [ 24,25 ] based on the different stimuli‐responsiveness mechanisms. [ 8 ] However, individual stimulus‐chromism provides limited functionalities for smart windows: most previous works focus on energy‐saving functionality only, [ 8,26 ] while giving less attention to other functionalities such as on‐demand privacy, aesthetic appearance, and so on.…”

Defense responses of the green microalgae Chlorella vulgaris to the vanadium pentoxide nanoparticles

“…The toxic impact of vanadium oxides on living organisms is influenced by different issues such as their solubility, concentration, length of treatment, and the type of treated cells (Xi et al 2019;Xi et al 2021). Vanadium pentoxide-based materials are broadly utilized in industrial products such as gas sensors (Niu et al 2021), solar cells (Costals et al 2021), smart glasses (Ma et al 2008), and smart windows (Li et al 2023). Notably, in situ experiments have demonstrated that paints containing V 2 O 5 NPs might inhibit the biofouling of surfaces in seawater (Natalio et al 2012).…”