Dual antireflection via reticulated superhydrophobic coating and etched glass substrate: Enhanced light trapping

Abstract

Currently, achieving both antireflection properties and self-cleaning superhydrophobicity in photovoltaic coatings remains highly challenging. The inherent trade-off between these two performances severely restricts the practical implementation of high-performance photovoltaic coatings. We propose a composite fabrication strategy that combines substrate etching with the construction of a porous mesh-like coating. This integrated structure establishes a dual antireflection system composed of a porous mesh coating and an etched substrate, which achieves primary and secondary antireflection effects and significantly improves overall optical transmittance. Compared with conventional single-layer coatings, the unique microstructures formed by substrate etching endow the composite system with better optical stability and hydrophobic durability. In this manuscript, glass substrates were etched and modified using a composite etchant composed of potassium sodium tartrate tetrahydrate and sodium citrate. By adjusting the solvent ratio to optimize solution dispersibility, a quasi-mesh self-cleaning coating was fabricated. The composite modified glass sample was finally obtained by assembling the mesh coating onto the etched substrate. The results demonstrate that the composite sample achieves an average light transmittance of 96.8% and a water contact angle of 153.5°. It maintains excellent hydrophobic and optical performances after multiple stability tests. When applied to solar cell encapsulation, the device retains 95% of the original cell's photoelectric conversion efficiency and exhibits a 6% efficiency improvement compared with cells encapsulated with bare glass. This confirms the promising feasibility and outstanding advantages of the coating described in this manuscript for photovoltaic applications.