Understanding the Doping Effect on NiO: Toward High-Performance Inverted Perovskite Solar Cells

Wei Chen, Yinghui Wu, Jing Fan, Aleksandra B. Djurišić, Fangzhou Liu, Ho Won Tam, Annie Ng, Charles Surya, Wai Kin Chan, Dong Wang, Zhu Bing He

Research output: Contribution to journalArticlepeer-review

119 Citations (Scopus)

Abstract

High-quality hole transport layers are prepared by spin-coating copper doped nickel oxide (Cu:NiO) nanoparticle inks at room temperature without further processing. In agreement with theoretical calculations predicting that Cu doping results in acceptor energy levels closer to the valence band maximum compared to gap states of nickel vacancies in undoped NiO, an increase in the conductivity in Cu:NiO films compared to NiO is observed. Cu in Cu:NiO can be found in both Cu+ and Cu2+ states, and the substitution of Ni2+ with Cu+ contributes to both increased carrier concentration and carrier mobility. In addition, the films exhibit increased work function, which together with the conductivity increase, enables improved charge transfer and extraction. Furthermore, recombination losses due to lower monomolecular Shockley-Read-Hall recombination are reduced. These factors result in an improvement of all photovoltaic performance parameters and consequently an increased efficiency of the inverted planar perovskite solar cells. A power conversion efficiency (PCE) exceeding 20% could be achieved for small-area devices, while PCE values of 17.41 and 18.07% are obtained for flexible devices and large area (1 cm2) devices on rigid substrates, respectively.

Original languageEnglish
JournalAdvanced Energy Materials
DOIs
Publication statusAccepted/In press - Jan 1 2018
Externally publishedYes

Keywords

  • Copper doping
  • DFT calculations
  • Flexible solar cells
  • Nickel oxide
  • Organometallic halide perovskites

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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