Symmetric Confined Growth of Superstructured Vanadium Dioxide Nanonet with a Regular Geometrical Pattern by a Solution Approach

Controllable self-assembly of ordered and regularly patterned semiconductor nanoarchitectures is of great interest in achieving fantastic functionalities and properties of nanomaterials in nanodevices. Here we demonstrate a symmetric confined growth methodology for fabricating a geometrically patterned and well-oriented two-dimensional nanonet by a solution growth. A uniform orthogonal VO₂ nanonet composed of single-crystalline nanowalls is self-assembled in a one-step process and exhibits single-crystal-like crystallographic characteristics. It is revealed that the 4-fold symmetric structure of (001) TiO₂ determines the orthogonal geometrical pattern of the nanonet; in addition, the interfacial mismatch energy controls the horizontal growth direction and morphology of one-dimensional nanocrystals competing with the surface energy. The unique VO₂ nanonet exhibits excellent thermochromic performances due to its self-generated porosity and sluggish phase transition. The initial optical modulation temperature is near room temperature. The solar modulating ability (ΔT_sol) is up to 11.82% with the maximum visible light transmittance (T_vis-max) more than 70%. The proposed growth strategy could be adopted in more systems to perform self-assembly of regularly patterned nanoarchitectures with well interconnectivity and preferred orientation, which offers promising opportunities for exploiting potential nanodevices in various applications.