The mismatched energy-level alignment and interface defects of the SnO₂ nanoparticles’ electron transport layer (ETL) and perovskite layer worsen the efficiency of the perovskite solar cell. Herein, we devise a multiple-function surface engineering of SnO₂ nanoparticles. TBA⁺ ions improve the dispersion and stability of colloidal T-SnO₂ nanoparticles and act as a bridge between the ETL and perovskite layer through the electrostatic interaction with anions, thus suppressing the charge recombination and reducing the energy loss. I^– ions passivate oxygen vacancies of SnO₂ nanoparticles but also halide vacancies of the perovskite layer. Furthermore, the conduction band edge of T-SnO₂ is enhanced to match the energy alignment with the perovskite, which reduces the energy offset for electron transfer. As a result, the champion solar cell based on T-SnO₂ presented a power conversion efficiency of 21.71% with a V_OC of 1.15 V and negligible hysteresis, which are much higher than those of the reference device.

中文翻译：

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SnO2 纳米颗粒的多功能表面工程实现高效钙钛矿太阳能电池

SnO ₂纳米粒子的电子传输层（ETL）和钙钛矿层的不匹配能级排列和界面缺陷使钙钛矿太阳能电池的效率恶化。在此，我们设计了 SnO ₂纳米颗粒的多功能表面工程。TBA ⁺离子提高了胶体T-SnO ₂纳米粒子的分散性和稳定性，并通过与阴离子的静电相互作用在ETL和钙钛矿层之间起桥梁作用，从而抑制了电荷复合并减少了能量损失。I ^-离子钝化 SnO ₂纳米粒子的氧空位，但也钝化钙钛矿层的卤化物空位。此外，T-SnO 的导带边缘₂被增强以匹配与钙钛矿的能量排列，这减少了电子转移的能量偏移。结果，基于 T-SnO ₂的冠军太阳能电池的功率转换效率为 21.71%，V _OC为 1.15 V，滞后可忽略不计，远高于参考器件的功率转换效率。