The defects present in metal halide perovskite are deleterious to both the performance and stability of photovoltaic devices. Consequently, there is an intense focus on developing defect mitigation strategies. Herein we report a facile strategy that employs methylammonium triiodide (MAI₃) as an additive to the perovskite precursor solution. We examine the effect of MAI₃ on the structural and optoelectronic properties by X-ray diffraction, density functional theory calculations, molecular dynamics simulations, solid-state nuclear magnetic resonance, steady-state, time-resolved photoluminescence (TRPL), and time-resolved terahertz spectroscopy (TRTS). Specifically, TRPL and TRTS show that MAI₃ suppresses nonradiative recombination and increases the charge carrier mobility. As a result, the champion device shows a power conversion efficiency (PCE) of 23.46% with a high fill factor of >80%. Furthermore, these devices exhibit enhanced operational stability, with the best device retaining ∼90% of its initial PCE under 1 sun illumination with maximum power point tracking for 350 h.

中文翻译：

---

用于高效钙钛矿太阳能电池缺陷工程的三碘化甲基铵

金属卤化物钙钛矿中存在的缺陷对光伏器件的性能和稳定性都是有害的。因此，人们非常关注开发缺陷缓解策略。在此，我们报告了一种简便的策略，该策略采用三碘化甲基铵 (MAI ₃ ) 作为钙钛矿前体溶液的添加剂。我们研究MAI的影响₃上的结构和光电特性通过X射线衍射，密度泛函理论计算，分子动力学模拟，固态核磁共振，稳态，时间分辨光致发光（TRPL），和时间分辨太赫兹光谱 (TRTS)。具体来说，TRPL 和 TRTS 表明 MAI ₃抑制非辐射复合并增加电荷载流子迁移率。因此，冠军设备的功率转换效率 (PCE) 为 23.46%，填充因子高达 80% 以上。此外，这些设备表现出增强的操作稳定性，最好的设备在 1 次阳光照射下保持其初始 PCE 的约 90%，最大功率点跟踪 350 小时。