ZnxMn1-xO Solid Solutions in the Rocksalt Structure: Optical, Charge Transport, and Photoelectrochemical Properties

Venkata S. Bhadram, Qian Cheng, Candace K. Chan, Yiqun Liu, Stephan Lany, Kai Landskron, Timothy A. Strobel

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Theoretical predictions of ZnO:MnO solid solutions (abbreviated here as ZMO) with the rocksalt-type structure suggest improved visible light absorption and suitable band edge positions for the overall water splitting reaction, but experimental efforts to produce such phases are limited by the low solubility of Zn within this structure type. Here, we produce solid solutions of ZnxMn1-xO, with x = 0.5 and 0.3 in the metastable rocksalt phase, using high-pressure and high-temperature (HPHT) techniques. X-ray diffraction and electron microscopy methods were employed to determine the crystal structure, chemical composition, and homogeneity on the submicron scale. The solid solutions exhibit increased optical absorbance in the visible spectral range as compared to those of the parent oxides ZnO and MnO. Our theoretical calculations for ZnxMn1-xO with x = 0.5, 0.25 predict band gaps of 2.53 and 2.98 eV, respectively, with an unusually large band gap bowing. Our calculations also show small effective electron mass for these materials indicating their potential for solar energy applications. Initial photoelectrochemical tests reveal that ZMO solid solutions are suitable for water oxidation and warrant further experimental optimization.

Original languageEnglish
Pages (from-to)260-266
Number of pages7
JournalACS Applied Energy Materials
Volume1
Issue number2
DOIs
Publication statusPublished - Feb 26 2018

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Keywords

  • band gap bowing
  • charge transport
  • high-pressure synthesis
  • metastable oxides
  • photoelectrochemical water-splitting

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Electrochemistry
  • Materials Chemistry
  • Electrical and Electronic Engineering

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