Analysis and fabrication of a photonic crystal based anti-reflective coating for photovoltaics generated by evolutionary optimization

TL;DR

This paper presents the optimization, analysis, and fabrication of multilayered photonic crystal anti-reflective coatings for photovoltaics, revealing new design principles through evolutionary algorithms and physical insights.

Contribution

It introduces a systematic optimization approach for photonic crystal coatings, uncovering regular structures and new design rules for improved photovoltaic anti-reflective layers.

Findings

Optimized multilayer structures emerge as regular photonic crystals.

The central photonic crystal acts as a light buffer.

External layers reduce impedance mismatch effectively.

Abstract

We optimize multilayered anti-reflective coatings for photovoltaic devices, using modern evolutionary algorithms. We apply a rigorous methodology to show that a given structure, which is particularly regular, emerge spontaneously in a very systematical way for a very broad range of conditions. The very regularity of the structure allows for a thorough physical analysis of how the designs operate. This allows to understand that the central part is a photonic crystal utilized as a buffer for light, and that the external layers have the purpose of reducing the impedance mismatch between the outer media and the Bloch mode supported by the photonic crystal. This shows how optimization can suggest new design rules and be considered as a source of inspiration. Finally, we fabricate these structures with easily deployable techniques.