Polymer thin films for antireflection coatings

Polymer thin films for antireflection (AR) coatings are reviewed, with particular emphasis on making different kinds of structures and establishing the relationships between structures and antireflective properties. Three kinds of main structures with antireflective properties, namely, homogeneous, inhomogeneous porous structures, and gradient-refractive-index structures, fabricated by “bottom up” or “top down” approaches are summarized. The transmittance of the polymer thin film can be increased to almost 100% in the single or broadband wavelength region (both of the visible and near-infrared region) by properly manipulating its structures. However, further studies are still needed to achieve reversible transmittance and multifunctional polymer AR due to the soft matter characteristic of polymers. In addition, the challenges of using polymer AR coatings still remain, such as poor solvent resistance, poor mechanical strength, and so on, which gives us the direction of future development for practical applications.