The under-coordinated defects within perovskite and its relevant interfaces always attract and trap the free carriers via the electrostatic force, significantly limiting the charge extraction efficiency and the intrinsic stability of perovskite solar cells (PSCs). Herein, self-diffusion interfacial doping by using ionic potassium L-aspartate (PL-A) is first reported to restrain the carrier trap induced recombination via the reconstruction of energy level structure at SnO₂/perovskite interface in conventional n-i-p structured PSCs. Experiments and theories are consistent with the PL-A anions that can remain at the SnO₂ surface due to strong chemical adsorption. During the spin-coating of the perovskite film, the cations gradually diffuse into perovskite and endow an n-doping effect, which provides higher force and a better energy level alignment for the carrier transport. As a result, they obtained 23.74% power conversion efficiency for the PL-A modified small-area devices, with dramatically improved open-circuit voltage of 1.19 V. The corresponding large-area devices (1.05 cm²) achieved an efficiency of 22.23%. Furthermore, the modified devices exhibited negligible hysteresis and enhanced ambient air stability exceeding 1500 h.

中文翻译：

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用于高效钙钛矿太阳能电池的稳健界面改性剂：通过掺杂剂的自扩散重建掩埋界面处的能量排列

钙钛矿及其相关界面中的欠协调缺陷总是通过静电力吸引和捕获自由载流子，从而显着限制了钙钛矿太阳能电池（PSC）的电荷提取效率和内在稳定性。在此，首次报道了使用离子型 L-天冬氨酸钾 (PL-A) 进行自扩散界面掺杂，通过在传统的nip结构 PSC中重建 SnO ₂ /钙钛矿界面处的能级结构来抑制载流子陷阱诱导的复合。实验和理论与 PL-A 阴离子可以保留在 SnO _{2上是一致的}表面由于强烈的化学吸附。在钙钛矿薄膜的旋涂过程中，阳离子逐渐扩散到钙钛矿中并赋予n型掺杂效应，从而为载流子传输提供更高的力和更好的能级排列。结果，他们获得了 23.74% 的 PL-A 改性小面积器件的功率转换效率，显着提高了 1.19 V 的开路电压。相应的大面积器件（1.05 cm ²）实现了 22.23% 的效率. 此外，改进后的器件表现出可忽略不计的滞后现象，并增强了超过 1500 小时的环境空气稳定性。