High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic-Inorganic Perovskite Solar Cells

Philip Schulz; Jan O Tiepelt; Jeffrey A Christians; Igal Levine; Eran Edri; Erin M Sanehira; Gary Hodes; David Cahen; Antoine Kahn

doi:10.1021/acsami.6b10898

High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic-Inorganic Perovskite Solar Cells

ACS Appl Mater Interfaces. 2016 Nov 23;8(46):31491-31499. doi: 10.1021/acsami.6b10898. Epub 2016 Nov 14.

Authors

Philip Schulz^{1

2}, Jan O Tiepelt¹, Jeffrey A Christians², Igal Levine³, Eran Edri³, Erin M Sanehira^{2

4}, Gary Hodes³, David Cahen³, Antoine Kahn¹

Affiliations

¹ Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
² National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
³ Department of Materials and Interfaces, Weizmann Institute of Science , Rehovot 76100, Israel.
⁴ Department of Electrical Engineering, University of Washington , Seattle, Washington 98195, United States.

PMID: 27933974
DOI: 10.1021/acsami.6b10898

Abstract

We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function molybdenum trioxide (MoO₃). We find that direct contact between MoO₃ and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI₃) layer at the interface still negatively impacts device performance.

Keywords: band offsets; charge carrier transport; electronic structures/processes/mechanisms; hybrid materials; photoemission spectroscopy; photovoltaic devices.