Fabrication and characterization of silica anti-reflective films with phosphoric acid template

• H3PO4 is used as the template agent in silica antireflective films.
• The transmittance of antireflective films is improved dramatically owing to the addition of H3PO4.
• The transmittance of films rises first and then decreases slightly with the decrease in H3PO4 concentration.

In this work, the feasibility is investigated and confirmed that H3PO4 is used as pore-forming agent in silica antireflective film. The films are prepared by sol–gel method and spinning-coating technique and studied by field-emission scanning electron microscopy (FE-SEM), visible spectroscopy and ellipsometer. The impact of H3PO4 concentration on transmittance is also examined. Transmittance spectra show that silica films feature a marked increase of substrate transmittance almost at all measured wavelengths (325–1000 nm) owing to the addition of H3PO4. With the decrease of H3PO4 concentration, films transmittance will rise first and then decrease slightly. And with an increase of 4.1%, a maximum light transmittance of 95.01% is obtained, which is comparable to some other antireflective films using organic templates.