Amorphous TiO2 Compact Layers via ALD for Planar Halide Perovskite Photovoltaics

In Soo Kim, Richard T. Haasch, Duyen H. Cao, Omar K. Farha, Joseph T. Hupp, Mercouri G. Kanatzidis, Alex B.F. Martinson

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


A low-temperature (<120 °C) route to pinhole-free amorphous TiO2 compact layers may pave the way to more efficient, flexible, and stable inverted perovskite halide device designs. Toward this end, we utilize low-temperature thermal atomic layer deposition (ALD) to synthesize ultrathin (12 nm) compact TiO2 underlayers for planar halide perovskite PV. Although device performance with as-deposited TiO2 films is poor, we identify room-temperature UV-O3 treatment as a route to device efficiency comparable to crystalline TiO2 thin films synthesized by higher temperature methods. We further explore the chemical, physical, and interfacial properties that might explain the improved performance through X-ray diffraction, spectroscopic ellipsometry, Raman spectroscopy, and X-ray photoelectron spectroscopy. These findings challenge our intuition about effective electron selective layers as well as point the way to a greater selection of flexible substrates and more stable inverted device designs.

Original languageEnglish
Pages (from-to)24310-24314
Number of pages5
JournalACS Applied Materials and Interfaces
Issue number37
Publication statusPublished - Sep 21 2016


  • amorphous titanium dioxide
  • atomic layer deposition
  • hybrid perovskites
  • low temperature processing
  • solar energy conversion

ASJC Scopus subject areas

  • Materials Science(all)

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