This article investigates metallization-induced recombination losses associated with the presence of silicon (Si) in the 1) rear passivation layers and 2) aluminum (Al) paste in fully screen-printed p-type passivated emitter and rear cell (PERC) solar cells. For 1), the rear sides of PERCs passivated with aluminum oxide films stacked with silicon nitride (SiNy) films with various refractive indexes (n), as defined by the composition of the SiNy films, were fabricated. Si-rich SiNy films strongly degraded the implied open-circuit voltages of symmetrically passivated samples, that include cells. Elemental mapping analysis confirmed further metallization-induced losses at the cell level because of the formation of an Al-Si alloy within the passivation stacks, with the density of the alloy dependent on the refractive index. For 2), the rear sides of PERCs were metallized with Si-free Al paste or Al pastes that contain Si. High-Si paste had both good and bad effects: it produced thicker aluminum back surface fields but left partially-formed Al-Si alloy within the passivation films.

中文翻译：

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全丝网印刷 p 型 PERC 太阳能电池背面金属化引起的损耗机制

本文研究了在完全丝网印刷的 p 型钝化发射极和背面电池 (PERC) 太阳能电池中与 1) 背面钝化层和 2) 铝 (Al) 浆料中存在硅 (Si) 相关的金属化诱导的复合损失. 对于 1)，制造用氧化铝薄膜钝化的 PERC 背面，该薄膜与氮化硅 (SiNy) 薄膜堆叠在一起，具有不同的折射率 (n)，由 SiNy 薄膜的组成定义。富含 Si 的 SiNy 薄膜强烈降低了对称钝化样品（包括电池）的隐含开路电压。由于在钝化堆叠内形成了 Al-Si 合金，元素映射分析进一步证实了电池级金属化引起的损失，合金的密度取决于折射率。对于 2), PERC 的背面用无硅铝浆或含硅铝浆进行金属化处理。高硅浆料有好有坏：它产生更厚的铝背面场，但在钝化膜内留下部分形成的铝硅合金。