AI 中文总结
该研究明确原始石墨烯薄片（GF）与氧化石墨烯薄片不可互换，通过理论计算与模拟结合发现GF可作为前驱体支架提升钙钛矿结晶，在混合锡-铅钙钛矿电池中将效率从21.5%提至23.7%并改善稳定性。
AI 中文摘要
石墨烯衍生物是用于改善金属卤化物钙钛矿器件体相和界面性能的广泛应用材料，但它们的薄片化学性质及其与钙钛矿前驱体的相互作用的影响仍不清楚。本文表明，原始石墨烯薄片（GF）与更常规的氧化石墨烯薄片（GOF）不可互换。密度泛函理论计算显示，GOF与钙钛矿晶格的相互作用更强，但会引发更大的结构畸变、更强的界面极化以及局域带隙态；相比之下，GF形成的接触相对无干扰，且该特性在宽成分范围内均能保持。机器学习原子模拟进一步表明，GF接触溶剂化钙钛矿纳米晶中含Pb和I的区域，且具有强溶剂依赖性。溶液光谱表征显示，GF添加剂作为预组织含Pb/I前驱体的支架，有利于薄膜结晶。从这个意义上讲，GF可提升不同成分钙钛矿的太阳能电池性能，尤其对结晶难度更大的钙钛矿效果显著；在混合锡-铅钙钛矿太阳能电池中，GF将冠军功率转换效率从21.5%提升至23.7%，同时改善了存储稳定性。这些结果确立了原始GF为化学明确的添加剂，并将其原子尺度相互作用与前驱体组织、结晶、器件性能及稳定性关联起来。
英文摘要
Graphene-derivatives are widely employed materials to improve bulk and interface properties of metal-halide perovskite devices. Yet the implications of their flake chemistry and interactions with the perovskite precursors remain unclear. Here, we show that pristine graphene flakes (GF) and more conventional graphene oxide flakes (GOF) are not interchangeable. Density functional theory calculations reveal that GOF interacts more strongly with the perovskite lattice but induces larger structural distortions, stronger interfacial polarisation, and localised gap states. In contrast, GF forms comparatively non-disruptive contacts, a response retained across a wide compositional range. Machine-learning atomistic simulations further show that GF contacts both Pb- and I-containing regions of solvated perovskite nanocrystals, with a strong solvent dependency. Solution spectroscopic characterization indicates that GF additives serve as scaffold for preorganised Pb/I-containing precursors, favouring film crystallisation. In this sense, GF enhances solar cell performance across perovskite compositions, but particularly those facing a more challenging crystallisation. In mixed Sn-Pb perovskite solar cells, GF raises the champion power-conversion efficiency from 21.5\% to 23.7\% with improved storage stability. These results establish pristine GF as a chemically defined additive and connect its atomic-scale interactions with precursor organisation, crystallisation, device performance, and stability.
Comments4 figures in main; 21 figures and 3 tables in the SI
