Fig. 1. Diagram of optimal spin-coating method.

Fig. 2. Properties of various pH values of SiO2 nanoparticle solution. (a) Particle distribution of various pH values of SiO2 nanoparticle solution measured by the DLS. (b) Transmittance of the AR coating fabricated with various pH values of the SiO2 solution. (c) Top-view SEM image of AR coating fabricated by various pH values of SiO2 solution.

Fig. 3. Transparency of the AR coating with various pH values of SiO2 solution under different incident angles. (a)–(c) Transmittance variation within the wavelength range from 400–900 nm. (d)–(f) Power ratio within an incident angle range of ±60°.

Fig. 4. Transparency of the AR coating with various pH values of SiO2 solution under different incident angles with p- and s-polarized light. (a) 0°, (b) 30°, and (c) 60°.

Fig. 5. Power ratio of the AR coating with various pH values of SiO2 solution under different incident angles with p-and s-polarized light measured within an incident angle range of ±60°. (a) pH 6, (b) pH 9, and (c) pH 11.

Fig. 6. Reflectance of the AR coating with various pH values of the SiO2 solution under p-polarized light. (a) Experimental results. (b) Theoretical simulation.

Fig. 7. Hydrophobic nature of the AR coating with various pH values of SiO2 solution. (a) pH 6, (b) pH 9, and (c) pH 11.