Outdoor Characterization of Solar Cells with Micro-structured Anti-Reflective Coating in a Concentrator Photovoltaic Module

TL;DR

This study demonstrates that micro-structured encapsulating anti-reflective coatings significantly enhance the performance of concentrator photovoltaic modules in outdoor conditions, with notable increases in current and power output.

Contribution

It introduces a novel micro-structured encapsulating ARC made of semi-buried silica beads in PDMS and evaluates its performance and reliability in real-world outdoor conditions.

Findings

12-14% increase in short-circuit current

15-19% increase in maximum power

29.7% sub-module efficiency at CSOC

Abstract

Micro-structured anti reflective coatings (ARC) have been identified as a promising solution to reduce optical losses in Concentrator Photovoltaics modules (CPV). We fabricated and tested in field a CPV modules made of 4 sub-modules with a concentration factor of 250x, that embed either solar cells with micro-structured encapsulating ARC or solar cells with multilayer ARC as a reference. The micro-structured encapsulating ARC was made of semi-buried silica beads in polydimethylsiloxane (PDMS). The module was in operation for 1 year in the severe climatic conditions of Sherbrooke, Quebec, Canada, before extracting the sub-modules performance under Concentrator Standard Operating Condition (CSOC). An acceptance angle of +/-0.78 degree was determined for all sub-modules, demonstrating that improving angular collection at the cell level has no significant impact on the angle of acceptance at the module level. We report an increase of 12 to 14% of the short-circuit current and of 15 to 19% of maximum power at CSOC for solar cells with a micro structured encapsulating ARC compared to the reference. Despite a sub-optimal module design, we report a sub-module efficiency of 29.7% at CSOC for a cell with micro-structured encapsulating ARC. This proves the potential of micro-structured encapsulating ARC to improve CPV system performance and shows promise of reliability for sumi-buried microbeads in PDMS as encapsulating ARC.