Efficient metal contact formation is pivotal for the production of cost-effective, high-performance crystalline silicon (Si) solar cells. Traditionally, screen-printed silver (Ag) contacts on the front surface have dominated the industry owing to their simplicity, high throughput, and significant electrical benefits. However, the high cost associated with using over 13–20 mg/Wp of Ag can impede the development of truly cost-effective solar cells. Therefore, there is an urgent need to explore alternative, economically viable metals compatible with silicon substrates. This study reports on the application of a contact stack consisting of Ag, nickel (Ni), and copper (Cu) in Si solar cells. To prevent Schottky contact formation, Ag is implemented as a seed layer, whereas Ni and Cu form the metal bulk layer. The fabricated bi-layer stack without selective emitter exhibits a maximum efficiency of ~21.5%, a fill factor of 81.5%, and an average contact resistance of 5.88 mΩ·cm² for a monofacial PERC cell. Microstructure analysis demonstrates that the metals within the contacts remain distinct, and Cu diffusion into the silicon during the firing process is absent. Consequently, printed bi-layer contacts emerge as a promising alternative to Ag contacts, reducing the Ag consumption to below 2.5 mg/Wp per cell without compromising overall efficiency.

中文翻译：

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在硅太阳能电池中采用镍和铜作为具有成本效益的替代触点

高效的金属接触形成对于生产具有成本效益的高性能晶体硅 (Si) 太阳能电池至关重要。传统上，前表面上的丝网印刷银 (Ag) 触点由于其简单性、高吞吐量和显着的电气优势而在行业中占据主导地位。然而，使用超过 13–20 mg/Wp 的 Ag 所带来的高成本可能会阻碍真正具有成本效益的太阳能电池的开发。因此，迫切需要探索与硅基底兼容的替代的、经济上可行的金属。本研究报告了由银、镍 (Ni) 和铜 (Cu) 组成的接触叠层在硅太阳能电池中的应用。为了防止形成肖特基接触，Ag 被用作种子层，而 Ni 和 Cu 形成金属体层。对于单面PERC电池，所制造的无选择性发射极的双层堆叠的最大效率为~21.5%，填充因子为81.5%，平均接触电阻为5.88 mΩ·cm ^{2 。}微观结构分析表明，触点内的金属保持清晰，并且在烧制过程中不存在铜扩散到硅中的情况。因此，印刷双层触点成为银触点的有前景的替代品，将每个电池的银消耗量降低至 2.5 mg/Wp 以下，而不会影响整体效率。