Organic–inorganic hybrid lead halide perovskites have gained significant attention as light-harvesting materials in thin-film photovoltaics due to their exceptional optoelectronic properties and simple fabrication process. The power conversion efficiency of perovskite solar cells (PSCs) has surged beyond 25% in a short time span. Their transition to commercial market is a “work in progress” due to limited long-term operational stability and the persisting environmental concern due to the presence of lead. Comprehensive investigations on the interplay of material composition and interfacial effects on the device performance of PSCs based on methylammonium lead iodide have shown the crucial role of an A-site cation in incipient deterioration of the material through external stimuli (moisture, light, oxygen, or heat). Consequently, a partial or complete replacement of A-site cations by up to four isoelectronic substituents has resulted in many new perovskite compositions. The correlations between the chemical composition and the optoelectronic properties are, however, not always easy to determine. A-site cation management is governed by stability and charge neutrality of the lattice, and the choices include Cs+-cations and organic cations such as CH3NH3+ or CH(NH2)2+ and combinations thereof. Since the size of the cations is an important structural parameter, an adequate compositional engineering of the A-site could effectively optimize the stability by reducing non-radiative defect sites and enhancing carrier lifetimes. This Perspective reflects on the experimental strategies for A-site cation management and their direct impact on the stability and device performance. It also highlights the opportunities and challenges for further research and industrial commercialization of PSCs.

中文翻译：

---

了解 A 位工程卤化铅钙钛矿稳定性和效率的相互作用

有机-无机杂化卤化铅钙钛矿由于其优异的光电性能和简单的制造工艺，作为薄膜光伏领域的集光材料受到了广泛关注。钙钛矿太阳能电池 (PSC) 的功率转换效率在短时间内飙升至 25% 以上。由于长期运营稳定性有限，以及铅的存在导致持续的环境问题，他们向商业市场的过渡是一项“正在进行的工作”。对材料成分的相互作用和界面效应对基于甲基碘化铅的 PSC 器件性能的综合研究表明，A 位阳离子在通过外部刺激（水分、光、氧气或热）。最后，用多达四个等电子取代基部分或完全取代 A 位阳离子已产生许多新的钙钛矿组合物。然而，化学成分和光电特性之间的相关性并不总是容易确定。A 位阳离子管理由晶格的稳定性和电荷中性控制，选择包括 Cs+-阳离子和有机阳离子，例如 CH3NH3+ 或 CH(NH2)2+ 及其组合。由于阳离子的大小是一个重要的结构参数，A 位的适当组成工程可以通过减少非辐射缺陷位和提高载流子寿命来有效优化稳定性。该观点反映了 A 位阳离子管理的实验策略及其对稳定性和器件性能的直接影响。