Vacuum-Induced Degradation of 2D Perovskites

Yvonne J Hofstetter; Inés García-Benito; Fabian Paulus; Simonetta Orlandi; Giulia Grancini; Yana Vaynzof

doi:10.3389/fchem.2020.00066

Vacuum-Induced Degradation of 2D Perovskites

Front Chem. 2020 Feb 13:8:66. doi: 10.3389/fchem.2020.00066. eCollection 2020.

Authors

Yvonne J Hofstetter^{1

2}, Inés García-Benito³, Fabian Paulus^{1

2}, Simonetta Orlandi⁴, Giulia Grancini^{3

5}, Yana Vaynzof^{1

2}

Affiliations

¹ Kirchhoff Institute for Physics and the Centre for Advanced Materials, Heidelberg University, Heidelberg, Germany.
² Integrated Centre for Applied Physics and Photonic Materials and Centre for Advancing Electronics Dresden (CFAED), Technical University of Dresden, Dresden, Germany.
³ Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, Sion, Switzerland.
⁴ CNR - Istituto di Scienze e Tecnologie Chimiche "G. Natta" (CNR-SCITEC), Milan, Italy.
⁵ Department of Chemistry, University of Pavia, Pavia, Italy.

Abstract

Two-dimensional (2D) hybrid organic-inorganic perovskites have recently attracted the attention of the scientific community due to their exciting optical and electronic properties as well as enhanced stability upon exposure to environmental factors. In this work, we investigate 2D perovskite layers with a range of organic cations and report on the Achilles heel of these materials-their significant degradation upon exposure to vacuum. We demonstrate that vacuum exposure induces the formation of a metallic lead species, accompanied by a loss of the organic cation from the perovskite. We investigate the dynamics of this reaction, as well as the influence of other factors, such as X-ray irradiation. Furthermore, we characterize the effect of degradation on the microstructure of the 2D layers. Our study highlights that despite earlier reports, 2D perovskites may exhibit instabilities, the chemistry of which should be identified and investigated in order to develop suitable mitigation strategies.

Keywords: 2D perovskites; X-ray photoemission spectroscopy; cations; stability; vacuum.