Metal halide perovskite materials are promising candidates for printable solar cells due to their feasibility for achieving high device efficiency at a low processing temperature. One of the key challenges in printed perovskite solar cell (PSC) research is to develop low-temperature-processable charge-transporting layers for both electron and hole-transporting materials, which can be used within large-scale roll-to-roll (R2R) printing techniques. Colloidal links allow for facile deposition, provided that the size of the nanoparticles (NPs) is controlled to less than a few tens of nanometres (ideally < 20 nm); they can be deposited as uniform films and can be processed at low temperatures (typically < 140 °C). Here, we report a facile and scalable route for the synthesis of SnO₂ NP dispersions using a microwave-assisted “benzyl alcohol” approach that is compatible with all of these R2R printing requirements. The method enables crystalline SnO₂ NPs to be synthesized with a controlled average particle size (∼6.5 nm) and be used directly as an ink without any post-synthesis purification (i.e., one-pot synthesis). The use of these SnO₂ NPs has been explored as an electron transport layer (ETL) within planar PSCs using spin-coating and thermal processing at 140 °C for 2 min, yielding devices with over 18% photo-conversion efficiency. Comparable devices were also fabricated using slot die-coated SnO₂ on glass substrates and R2R-coated SnO₂ on plastic substrates, yielding efficiencies of 15.3 and 10.4%, respectively. Our results demonstrate the suitability of the developed SnO₂ ink to be used for the deposition of ETLs in optoelectronic devices by industrial-scale R2R printing processes.

中文翻译：

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非水一锅二氧化锡纳米粒子墨水及其在可印刷钙钛矿太阳能电池中的应用

金属卤化物钙钛矿材料因其在低加工温度下实现高器件效率的可行性而成为可印刷太阳能电池的有希望的候选材料。印刷钙钛矿太阳能电池 (PSC) 研究的主要挑战之一是开发用于电子和空穴传输材料的低温可加工电荷传输层，该层可用于大规模卷对卷 (R2R) ) 印刷技术。如果将纳米颗粒 (NP) 的尺寸控制在小于几十纳米（理想情况下小于 20 nm），则胶体连接可以轻松沉积；它们可以沉积为均匀的薄膜，并且可以在低温（通常 < 140 °C）下进行加工。在这里，我们报告了一种用于合成 SnO _{2的简便且可扩展的路线}使用符合所有这些 R2R 打印要求的微波辅助“苯甲醇”方法的 NP 分散体。该方法能够合成具有可控平均粒径（~6.5 nm）的结晶SnO ₂ NPs，并且无需任何合成后纯化（即一锅法合成）即可直接用作油墨。已探索使用这些 SnO ₂ NPs 作为平面 PSC 内的电子传输层 (ETL)，使用旋涂和热处理在 140°C 下进行 2 分钟，产生具有超过 18% 的光转换效率的器件。还使用玻璃基板上的槽模涂层 SnO ₂和 R2R 涂层 SnO _{2制造了类似的器件}在塑料基板上，效率分别为 15.3% 和 10.4%。我们的结果证明了所开发的 SnO ₂墨水适用于通过工业规模的 R2R 印刷工艺在光电器件中沉积 ETL。