Control of Surface Defects in ZnO Nanorod Arrays with Thermally Deposited Au Nanoparticles for Perovskite Photovoltaics

Tulus Tulus, Selina Olthof, Magdalena Marszalek, Andreas Peukert, Loreta A. Muscarella, Bruno Ehrler, Olivera Vukovic, Yulia Galagan, Simon Christian Boehme, Elizabeth Von Hauff*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

In this work, we employ vacuum deposited Au nanoparticles (-4 nm) to control the defect density on the surface of hydrothermally synthesized ZnO nanorod arrays (ZnO-NR), which are of interest for electron-transport layers in perovskite solar cells. Using a combination of photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy, we show that the Au particles reduce the presence of defects in the ZnO-NR. We discuss this in terms of trap filling due to band bending at the ZnO-NR surface. As a proof-of-concept, we apply the Au-decorated ZnO-NR as electron-transport layers in mixed-cation and mixed-halide lead perovskite solar cells (Cs0.15FA0.85PbI2.75Br0.25). Devices prepared with the Au-decorated ZnO-NR electron-transport layers demonstrate higher open-circuit voltages and fill factors compared to solar cells prepared with pristine ZnO-NR, resulting in an increase in the power-conversion efficiency from 11.7 to 13.7%. However, the operational stability of the solar cells is not improved by the Au nanoparticles, indicating that bulk properties of the perovskite may limit device lifetime.

Original languageEnglish
Pages (from-to)3736-3748
Number of pages13
JournalACS Applied Energy Materials
Volume2
Issue number5
Early online date26 Apr 2019
DOIs
Publication statusPublished - 28 May 2019

Keywords

  • defects
  • interface
  • mixed cation
  • mixed halide
  • perovskite photovoltaics
  • photoelectron spectroscopy
  • transport layer
  • ZnO nanostructures

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