Doped polysilicon (poly-Si) passivating contacts have emerged as a key technology for the next generation of silicon solar cells in mass production, owing to their excellent performance and high compatibility with the existing passivated emitter and rear cell technology. However, the current solar cell architecture based on a rear-side electron-selective (n+) poly-Si contact is also approaching its practical limit (∼26%) in mass production. The full potential of doped poly-Si passivating contacts can only be realized through incorporation of both electron-selective and hole-selective (p+) poly-Si contacts. While studies of both p+ and n+ poly-Si contacts commenced simultaneously, significant performance differences have arisen. Phosphorus-doped poly-Si contacts consistently outperform boron-doped counterparts, displaying typically lower recombination current density (J0) values (1–5fA/cm2 vs 7–15fA/cm2). This discrepancy can be attributed to inadequate optimization of p+ poly-Si contacts and fundamental limitations related to boron doping. The poorer passivation of p+ poly-Si contacts can be at least partly attributed to boron segregation into the interfacial oxide layers, compromising the interfacial oxide integrity and reducing the chemical passivation effectiveness. This review critically examines the progress of p+ poly-Si contacts characterized by cell efficiency and J0 values, delves into existing challenges, identifies potential solutions, and explores some potential solar cell architectures to enhance efficiency by incorporating p+ poly-Si contacts.

中文翻译：

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空穴选择性多晶硅钝化接触的现状和挑战

掺杂多晶硅（poly-Si）钝化接触由于其优异的性能以及与现有钝化发射极和背面电池技术的高度兼容性，已成为下一代硅太阳能电池量产的关键技术。然而，当前基于背面电子选择性（n+）多晶硅接触的太阳能电池架构也正在接近其大规模生产的实际极限（∼26%）。掺杂多晶硅钝化接触的全部潜力只能通过结合电子选择性和空穴选择性（p+）多晶硅接触来实现。虽然 p+ 和 n+ 多晶硅接触的研究同时开始，但出现了显着的性能差异。磷掺杂多晶硅触点的性能始终优于硼掺杂对应物，通常表现出较低的复合电流密度 (J0) 值（1–5fA/cm2 与 7–15fA/cm2）。这种差异可归因于 p+ 多晶硅接触的优化不充分以及与硼掺杂相关的基本限制。 p+多晶硅接触的较差钝化至少部分归因于硼偏析到界面氧化物层中，损害了界面氧化物的完整性并降低了化学钝化效果。本综述严格审查了以电池效率和 J0 值为特征的 p+ 多晶硅接触的进展，深入研究了现有的挑战，确定了潜在的解决方案，并探索了一些潜在的太阳能电池架构，以通过结合 p+ 多晶硅接触来提高效率。