Hole Doping in Al-Containing Nickel Oxide Materials To Improve Electrochromic Performance

Feng Lin, Dennis Nordlund, Tsu Chien Weng, Rob G. Moore, Dane T. Gillaspie, Anne C. Dillon, Ryan M. Richards, Chaiwat Engtrakul

Research output: Contribution to journalArticlepeer-review

106 Scopus Citations


Electrochromic materials exhibit switchable optical properties that can find applications in various fields, including smart windows, nonemissive displays, and semiconductors. High-performing nickel oxide electrochromic materials have been realized by controlling the material composition and tuning the nanostructural morphology. Post-treatment techniques could represent efficient and cost-effective approaches for performance enhancement. Herein, we report on a post-processing ozone technique that improves the electrochromic performance of an aluminum-containing nickel oxide material in lithium-ion electrolytes. The resulting materials were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, and X-ray absorption spectroscopy (XAS). It was observed that ozone exposure increased the Ni oxidation state by introducing hole states in the NiO6 octahedral unit. In addition, ozone exposure gives rise to higher-performing aluminum-containing nickel oxide films, relative to nickel oxide containing both Al and Li, in terms of switching kinetics, bleached-state transparency, and optical modulation. The improved performance is attributed to the decreased crystallinity and increased nickel oxidation state in aluminum-containing nickel oxide electrochromic films. The present study provides an alternative route to improve electrochromic performance for nickel oxide materials.

Original languageAmerican English
Pages (from-to)301-309
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number2
StatePublished - 23 Jan 2013

NREL Publication Number

  • NREL/JA-5900-56600


  • aluminum
  • electrochromic
  • lithium
  • nickel oxide
  • oxidation state
  • ozone


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