Impact of Black Silicon on Light- and Elevated Temperature-Induced Degradation in Industrial Passivated Emitter and Rear Cells

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Beneq Oy
  • SolarWorld Industries GmbH
  • SolarWorld Innovations GmbH

Abstract

Light and elevated-temperature induced degradation (LeTID) is currently a severe issue in passivated emitter and rear cells (PERC). In this work, we study the impact of surface texture, especially a black silicon (b-Si) nanostructure, on LeTID in industrial p-type mc-Si PERC. Our results show that during standard
LeTID conditions the b-Si cells with atomic-layer-deposited aluminum oxide (AlOx) front surface passivation show no degradation despite the presence of a hydrogen-rich AlOx/SiNx passivation stack on the rear. Furthermore, b-Si solar cells passivated with silicon nitride (SiNx) on the front lose only 1.5 %rel of their initial power conversion efficiency, while the acidic-textured equivalents degrade by nearly 4 %rel under the same conditions. Correspondingly, clear degradation is visible in the IQE of the acidic-textured cells, especially in the ~850–1100 nm wavelength range confirming that the degradation occurs in the bulk, while the IQE remains nearly unaffected in the b-Si cells. The observations are supported by spatially-resolved photoluminescence (PL) maps, which show a clear contrast in the degradation behavior of b-Si and acidic-textured cells, especially in the case of SiNx front surface passivation. The PL maps also suggest that the magnitude of LeTID scales with surface area of the texture, rather than wafer thickness that was recently reported, although the b-Si cells are slightly thinner (140 vs. 165 µm). The results indicate that b-Si has a positive impact on LeTID, and hence, benefits provided by b-Si are not limited only to the excellent optical properties, as commonly understood.

Details

Original languageEnglish
Number of pages14
JournalProgress in Photovoltaics
Early online date4 Dec 2018
Publication statusE-pub ahead of print - 4 Dec 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • black silicon, light-induced degradation, light- and elevated temperature-induced degradation, multicrystalline silicon, passivated emitter and rear cells, solar cells

ID: 28772390