Role of Chloride in the Morphological Evolution of Organo-Lead Halide Perovskite Thin Films

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• 作者：Spencer T. Williams ; Fan Zuo ; Chu-Chen Chueh ; Chien-Yi Liao ; Po-Wei Liang ; Alex K.-Y. Jen
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：10640-10654
• 全文大小：1019K
• ISSN：1936-086X

文摘

A comprehensive morphological study was used to elucidate chloride鈥檚 role in CH₃NH₃PbI_3鈥?i>xCl_x film evolution on a conducting polymer, PEDOT:PSS. Complex ion equilibria and aggregation in solution, as well as the role they play in nucleation, are found to ultimately be responsible for the unique morphological diversity observed in perovskite films grown in the presence of the chloride ion. An intermediate phase that is generated upon deposition and initial annealing templates continued self-assembly in the case of CH₃NH₃PbI_3鈥?i>xCl_x. In the absence of chloride, the film growth of CH₃NH₃PbI₃ is directed by substrate interfacial energy. By employing the through-plane TEM analysis, we gain detailed insight into the unique crystallographic textures, grain structures, and elemental distributions across the breadth of films grown from precursor solutions with different chemistries. The lattice coherence seen in morphologies generated under the influence of chloride provides a physical rational for the enhancement in carrier diffusion length and lifetime.

Keywords:

perovskite; chloride; crystallization mechanism; planar heterojunction; electron diffraction