Inorganic CsPbI2Br perovskites solar cells (PSCs) have attracted extensive interest owing to their outstanding optoelectronic properties. Nevertheless, the undesirable perovskite film quality and severe charge recombination dramatically restrict their performance improvement. Herein, we propose an additive strategy to modulate the CsPbI2Br crystallization process and reduce the defect density by adding 3-(1-pyridinio)-1-propanesulfonate (PPS) zwitterionic molecules into the perovskite precursor solution. The incorporation of PPS zwitterion can not only retard the crystal growth rate of CsPbI2Br with uniform morphology and enlarged grain size, but also effectively passivate defects via interacting with the uncoordinated sites in the perovskite film. In addition, the PPS zwitterion greatly ameliorates the energy level alignments at the interface. Thus, the photogenerated carriers are more efficiently extracted, and the nonradiative recombination is significantly suppressed. With these benefits, the optimized PPS-based CsPbI2Br device delivers a champion efficiency of 16.37% with high open-circuit voltage (VOC) of 1.302 V in contrast to the pristine device with an inferior efficiency of 14.26% (VOC of 1.183 V). In addition, the unencapsulated device with PPS presents improved long-term stability by preserving ∼85% of the initial efficiency after 760 h storage in ambient atmosphere. These findings provided important insights into the additive strategy of using zwitterionic materials for constructing efficient and stable inorganic PSCs.

中文翻译：

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Zwitterion 添加剂辅助晶体生长调控和缺陷钝化在高性能无机钙钛矿太阳能电池中的应用


无机 CsPbI2Br 钙钛矿太阳能电池 （PSC） 因其出色的光电性能而引起了广泛的兴趣。然而，不良的钙钛矿薄膜质量和严重的电荷复合极大地限制了它们的性能改进。在此，我们提出了一种加成策略，通过在钙钛矿前驱体溶液中加入 3-（1-吡啶）-1-丙磺酸盐 （PPS） 两性离子分子来调节 CsPbI2Br 结晶过程并降低缺陷密度。PPS 两性离子的掺入不仅可以延缓形貌均匀、晶粒尺寸增大的 CsPbI2Br 的晶体生长速率，还可以通过与钙钛矿薄膜中不配位点的相互作用有效地钝化缺陷。此外，PPS 两性离子大大改善了界面处的能级对齐。因此，光生载体被更有效地提取，非辐射复合被显着抑制。凭借这些优势，优化的基于 PPS 的 CsPbI2Br 器件可提供 16.37% 的冠军效率，开路电压 （VOC） 高达 1.302 V，而原始器件的效率较低，为 14.26%（VOC 为 1.183 V）。此外，采用 PPS 的未封装器件在环境气氛中储存 760 小时后仍能保持 ∼85% 的初始效率，从而提高了长期稳定性。这些发现为使用两性离子材料构建高效稳定的无机 PSC 的加成策略提供了重要见解。