Issue 5, 2015

Direct observation of an inhomogeneous chlorine distribution in CH3NH3PbI3−xClx layers: surface depletion and interface enrichment

Abstract

We have used hard X-ray photoelectron spectroscopy (HAXPES) at different photon energies and fluorescence yield X-ray absorption spectroscopy (FY-XAS) to non-destructively investigate CH3NH3PbI3−xClx perovskite thin films on compact TiO2. This combination of spectroscopic techniques allows the variation of information depth from the perovskite layer surface to the top-most part of the underlying compact TiO2 layer. We have taken advantage of this to understand the distribution of chlorine throughout the perovskite/TiO2 layer stack. No Cl is detected using HAXPES, indicating surface depletion of Cl and allowing us to place an upper limit on the amount of Cl in the perovskite layer: x < 0.07 and x < 0.40 to depths of ∼10 nm and ∼26 nm, respectively, beneath the perovskite film surface. Our FY-XAS results, however, demonstrate that there is a higher average concentration of Cl throughout the perovskite layer than at the surface (x > 0.40) consistent with both enhanced concentrations of Cl deep beneath the perovskite film surface and near the CH3NH3PbI3−xClx perovskite/TiO2 interface. The consequences of this distribution of Cl in the CH3NH3PbI3−xClx perovskite layer on device performance are discussed.

Graphical abstract: Direct observation of an inhomogeneous chlorine distribution in CH3NH3PbI3−xClx layers: surface depletion and interface enrichment

Supplementary files

Article information

Article type
Paper
Submitted
05 Febr. 2015
Accepted
21 Apr. 2015
First published
21 Apr. 2015

Energy Environ. Sci., 2015,8, 1609-1615

Author version available

Direct observation of an inhomogeneous chlorine distribution in CH3NH3PbI3−xClx layers: surface depletion and interface enrichment

D. E. Starr, G. Sadoughi, E. Handick, R. G. Wilks, J. H. Alsmeier, L. Köhler, M. Gorgoi, H. J. Snaith and M. Bär, Energy Environ. Sci., 2015, 8, 1609 DOI: 10.1039/C5EE00403A

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.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements