Critical Intermediate Structure That Directs the Crystalline Texture and Surface Morphology of Organo-Lead Trihalide Perovskite

Hao Chung Chia, Hwo Shuenn Sheu, Yu Yun Hsiao, Shao Sian Li, Yi Kang Lan, Chung Yao Lin, Je Wei Chang, Yen Chien Kuo, Chia Hao Chen, Shih Chang Weng, Chun Jen Su, An Chung Su, Chun Wei Chen, U. Ser Jeng

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

We have identified an often observed yet unresolved intermediate structure in a popular processing with dimethylformamide solutions of lead chloride and methylammonium iodide for perovskite solar cells. With subsecond time-resolved grazing-incidence X-ray scattering and X-ray photoemission spectroscopy, supplemental with ab initio calculation, the resolved intermediate structure (CH3NH3)2PbI2Cl2·CH3NH3I features two-dimensional (2D) perovskite bilayers of zigzagged lead-halide octahedra and sandwiched CH3NH3I layers. Such intermediate structure reveals a hidden correlation between the intermediate phase and the composition of the processing solution. Most importantly, the 2D perovskite lattice of the intermediate phase is largely crystallographically aligned with the [110] planes of the three-dimensional perovskite cubic phase; consequently, with sublimation of Cl ions from the organo-lead octahedral terminal corners in prolonged annealing, the zigzagged octahedral layers of the intermediate phase can merge with the intercalated methylammonium iodide layers for templated growth of perovskite crystals. Regulated by annealing temperature and the activation energies of the intermediate and perovskite, deduced from analysis of temperature-dependent structural kinetics, the intermediate phase is found to selectively mature first and then melt along the layering direction for epitaxial conversion into perovskite crystals. The unveiled epitaxial conversion under growth kinetics controls might be general for solution-processed and intermediate-templated perovskite formation.

Original languageEnglish
Pages (from-to)36897-36906
Number of pages10
JournalACS Applied Materials and Interfaces
Volume9
Issue number42
DOIs
Publication statusPublished - Oct 25 2017
Externally publishedYes

Keywords

  • crystal growth kinetics
  • grazing-incidence X-ray scattering
  • intermediate-templated conversion
  • Organo-lead trihalide perovskite
  • X-ray photoemission spectroscopy

ASJC Scopus subject areas

  • General Materials Science

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