Honeycomb Structure on Multi-crystalline Silicon Al-BSF Solar Cell With 17.8% Efficiency

In this paper, large-area honeycomb (HC) texturing of multi-crystalline Si substrates with a newly developed process chain based on roller nanoimprint lithography and inline-capable plasma etching is demonstrated. The realized HC-textures show optical properties superior to random pyramids on c-Si, while the surface passivation quality is comparable. First, results on 156 × 156 mm² multi-crystalline Si solar cells with an aluminum back-surface field show an efficiency of η = 17.8% compared with η = 17.3% on isotextured reference samples. This efficiency gain of 0.5% results from an increase in J_sc of up to 1.3 mA/cm², which underlines the high optical and electrical quality of the texture. On a smaller area (50 × 50 mm²), the gain in J_sc of HC-textured cells compared with isotextured references was even higher with up to 2.5 mA/cm².