Annealing-induced chemical and structural changes in tri-iodide and mixed-halide organometal perovskite layers

Teng Ma; Matteo Cagnoni; Daisuke Tadaki; Ayumi Hirano-Iwata; Michio Niwano

doi:10.1039/C5TA03039K

Annealing-induced chemical and structural changes in tri-iodide and mixed-halide organometal perovskite layers†

Teng Ma,^ab Matteo Cagnoni,^a Daisuke Tadaki,^bc Ayumi Hirano-Iwata^bc and Michio Niwano*^ab

* Corresponding authors

^a Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
E-mail: mateng@riec.tohoku.ac.jp
Fax: +81 22 217 5503
Tel: +81 22 217 5502

^b CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan

^c Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
E-mail: ahirano@bme.tohoku.ac.jp

Abstract

The annealing process is crucial for obtaining high-quality perovskite layers used in highly efficient planar perovskite solar cells. In this study, we have investigated the annealing-induced chemical and structural changes of tri-iodide (TI) and mixed-halide (MH) organometal perovskite layers using infrared absorption spectroscopy, scanning electron microscopy and X-ray diffraction measurements. For TI layers, the solvent molecules, dimethylformamide (DMF), remained in the form of the PbI₂/DMF compound after drying at room temperature. During annealing, the DMF evaporated to form PbI₂ crystals. When the MH perovskite film was annealed, both CH₃NH₃PbCl₃ and CH₃NH₃PbI₃ crystals were initially formed from an amorphous phase. With further annealing, the CH₃NH₃PbI₃ crystals gradually grew through the incorporation of source materials supplied from the CH₃NH₃PbCl₃ crystals and the amorphous phase and the slow evaporation of methylammonium (MA) and chloride ions. The resultant MH perovskite layer after annealing was mainly composed of large CH₃NH₃PbI₃ grains with a trace of chloride ions. We suggest that the difference in composition and structure leads to different charge transport properties of the TI and MH perovskite layers.

This article is part of the themed collection: 2015 Journal of Materials Chemistry A Hot Papers

Supplementary files

Article information

DOI: https://doi.org/10.1039/C5TA03039K
Article type: Paper
Submitted: 26 Apr 2015
Accepted: 04 Jun 2015
First published: 05 Jun 2015

Download Citation

J. Mater. Chem. A, 2015,3, 14195-14201

Permissions

Request permissions

Annealing-induced chemical and structural changes in tri-iodide and mixed-halide organometal perovskite layers

T. Ma, M. Cagnoni, D. Tadaki, A. Hirano-Iwata and M. Niwano, J. Mater. Chem. A, 2015, 3, 14195 DOI: 10.1039/C5TA03039K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Journal of Materials Chemistry A

Annealing-induced chemical and structural changes in tri-iodide and mixed-halide organometal perovskite layers†

Abstract

Supplementary files

Article information

Download Citation

Permissions

Annealing-induced chemical and structural changes in tri-iodide and mixed-halide organometal perovskite layers

Social activity

Search articles by author

Spotlight

Advertisements