Substrate-Controlled Band Positions in CH3NH3PbI3 Perovskite Films

Elisa M. Miller, Yixin Zhao, Candy C. Mercado, Sudip K. Saha, Joseph M. Luther, Kai Zhu, Vladan Stevanović, Craig L. Perkins, Jao Van De Lagemaat

Research output: Contribution to journalArticlepeer-review

182 Scopus Citations

Abstract

Using X-ray and ultraviolet photoelectron spectroscopy, the surface band positions of solution-processed CH3NH3PbI3 perovskite thin films deposited on an insulating substrate (Al2O3), various n-type (TiO2, ZrO2, ZnO, and F: SnO2 (FTO)) substrates, and various p-type (PEDOT: PSS, NiO, and Cu2O) substrates are studied. Many-body GW calculations of the valence band density of states, with spin-orbit interactions included, show a clear correspondence with our experimental spectra and are used to confirm our assignment of the valence band maximum. These surface-sensitive photoelectron spectroscopy measurements result in shifting of the CH3NH3PbI3 valence band position relative to the Fermi energy as a function of substrate type, where the valence band to Fermi energy difference reflects the substrate type (insulating-, n-, or p-type). Specifically, the insulating- and n-type substrates increase the CH3NH3PbI3 valence band to Fermi energy difference to the extent of pinning the conduction band to the Fermi level; whereas, the p-type substrates decrease the valence band to Fermi energy difference. This observation implies that the substrate’s properties enable control over the band alignment of CH3NH3PbI3 perovskite thin-film devices, potentially allowing for new device architectures as well as more efficient devices.

Original languageAmerican English
Pages (from-to)22122-22130
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number40
DOIs
StatePublished - 24 Sep 2014

NREL Publication Number

  • NREL/JA-5900-62486

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