Details

Autor(en) / Beteiligte

• Maischner, Felix
• Maus, Stephan
• Greulich, Johannes
• Lohmüller, Sabrina
• Lohmüller, Elmar
• Saint‐Cast, Pierre
• Ourinson, Daniel
• Vahlman, Henri
• Hergert, Karin
• Riepe, Stephan
• Glunz, Stefan
• Rein, Stefan

Titel

LeTID mitigation via an adapted firing process in p‐type PERC cells from SMART cast‐monocrystalline, Czochralski and high‐performance multicrystalline silicon

Ist Teil von

• Progress in photovoltaics, 2022-02, Vol.30 (2), p.123-131

Ort / Verlag

Bognor Regis: Wiley Subscription Services, Inc

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Wiley Online Library (Online service)

Beschreibungen/Notizen

• In this work, we analyse passivated emitter and rear cells (PERC), based on wafers made from seed manipulation for artificially controlled defects technique (SMART) monocrystalline silicon, magnetically grown and conventional Czochralski (mCz and Cz) silicon, and high‐performance multicrystalline (hpm) silicon. All wafers were processed identically except for the hpm wafers, which received an acidic texture instead of random pyramids. The energy conversion efficiency η of the SMART cells of 21.4 % is similar to the mCz cells (21.5 %) while being more than 1.9%abs higher than for the hpm cells. Furthermore, we here show for the first time that light‐ and elevated temperature‐induced degradation (LeTID) is mitigated in hpm, Cz and SMART PERC cells without significant losses in initial efficiency by an adapted fast‐firing process, incorporating slower firing ramps that can be used in industrial production. The cells that are fired with these ramps show no significant efficiency loss ( 1%rel<Δη<2%rel) during LeTID testing at 75°C and 0.15 suns illumination for 1100 h, while the reference fast‐firing process results in efficiency losses of 5%rel<Δη<6%rel due to LeTID. For Cz cells that have been treated to regenerate the boron–oxygen defect prior to LeTID testing, the maximum degradation was reduced from Δη≈3%rel to Δη≈1.5%rel. LeTID in boron‐doped PERC cells can be greatly mitigated by slightly lowering the cooling rate to 50 K/s during contact firing. This procedure does not influence the initial efficiency after firing. For SMART mono‐cast and hpm cells, the maximum efficiency degradation during LeTID testing under 0.15 suns at 75°C for 1100 h was reduced from 5%rel<Δη<6%rel to 1%rel<Δη<2%rel.