Significant reduction in NiO band gap upon formation of Lix Ni1-xO alloys: Applications to solar energy conversion

Nima Alidoust, Maytal Caspary Toroker, John A. Keith, Emily A. Carter

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


Long-term sustainable solar energy conversion relies on identifying economical and versatile semiconductor materials with appropriate band structures for photovoltaic and photocatalytic applications (e.g., band gaps of ∼1.5-2.0 eV). Nickel oxide (NiO) is an inexpensive yet highly promising candidate. Its charge-transfer character may lead to longer carrier lifetimes needed for higher efficiencies, and its conduction band edge is suitable for driving hydrogen evolution via water-splitting. However, NiO's large band gap (∼4 eV) severely limits its use in practical applications. Our first-principles quantum mechanics calculations show band gaps dramatically decrease to ∼2.0 eV when NiO is alloyed with Li2O. We show that LixNi1-xO alloys (with x=0.125 and 0.25) are p-type semiconductors, contain states with no impurity levels in the gap and maintain NiO's desirable charge-transfer character. Lastly, we show that the alloys have potential for photoelectrochemical applications, with band edges well-placed for photocatalytic hydrogen production and CO2 reduction, as well as in tandem dye-sensitized solar cells as a photocathode.

Original languageEnglish (US)
Pages (from-to)195-201
Number of pages7
Issue number1
StatePublished - Jan 2014

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • General Energy
  • General Materials Science
  • Environmental Chemistry


  • Band gap engineering
  • Dye-sensitized solar cells
  • Energy conversion
  • Photocatalysis
  • Photovoltaics


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