兰州大学曹靖报道了芳香钝化剂中的大极化子改善了钙钛矿颗粒间的电荷传输，从而提高了24%的光电效率。相关研究成果于2022年1月11日发表于国际一流学术期刊《德国应用化学》。

具有大π-骨架的芳香族钝化剂，如卟啉，在多晶钙钛矿薄膜中增强载流子，从而制备高效稳定的钙钛矿太阳能电池（PSCs）已引起人们的广泛关注。然而，它们往往自组装成超分子，从而可能影响钙钛矿晶界的电荷转移过程。

通过在钙钛矿薄膜中掺杂一种单胺铜卟啉，研究人员在钙钛矿晶粒之间成功地制备了两种基于卟啉的自组装超分子。晶体结构和理论分析表明，在其中一个超分子中，胺单元和相邻卟啉的中心铜离子之间存在较强的相互作用，这对卟啉的偶极方向有修正作用，在周期晶格中被量子化为均匀大极化子（HLPs）。卟啉超分子可以稳定钙钛矿晶界，大大提高PSC的稳定性，而HLPs功能超分子有利于空穴在钙钛矿晶粒间的传输，显著提高电池性能，高达24.2%。

该研究工作首次证明，调节芳香族钝化剂的分子间相互作用以产生HLP，对于钙钛矿晶粒间电荷传输的级联加速至关重要。

附：英文原文

Title: Homogeneously Large Polarons in Aromatic Passivators Improves Charge Transport Between Perovskite Grains for >24% Efficiency in Photovoltaics

Author: Jia-Hui Zhao, Xijiao Mu, Luyao Wang, Zihan Fang, Xiaoxin Zou, Jing Cao

Issue&Volume: 2022-01-11

Abstract: Aromatic passivators, such as porphyrin, with large π-backbones have drawn considerable attention to boost the charge carrier in polycrystalline perovskite films, thus fabricating efficient and stable perovskite solar cells (PSCs). However, they often   self-assemble into supramolecules to probably influence the charge-transfer process in perovskite grain boundary. Here, by doping a monoamine Cu porphyrin into perovskite films, two porphyrin-based self-assembled supramolecules were successfully prepared between perovskite grains. Crystal structures and theoretical analyses reveal the  presence of stronger interaction between amine units and central Cu ions of neighbouring porphyrins in one of the supramolecules, which has a modified effect on the dipole direction of porphyrins  to be quantized as  homogeneously large polarons (HLPs)  in a periodic lattice. The porphyrin supramolecules can stabilize perovskite grain boundaries to greatly improve the stability of PSCs, while the HLPs-featured supramolecule facilitates hole transport across perovskite grains to remarkably increase the cell performance as high as 24.2%. This work firstly proves that the modulation of intermolecular interaction of aromatic passivators to yield HLPs is crucial for the cascaded acceleration of charge transport between perovskite grains.

DOI: 10.1002/anie.202116308

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202116308