Chromogenic Amorphous MoO3- xNanosheets and Their Nanostructured Films for Smart Window Applications

Masahito Morita, Satoshi Toyoda, Hisao Kiuchi, Takeshi Abe, Kazuhiro Kumagai, Takahiro Saida, Katsutoshi Fukuda

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Amorphous molybdenum trioxide (a-MoO3-x) nanosheets of approximately 1.5 nm thickness were synthesized via pseudo-topotactic reactions of two-dimensional MoO2 nanosheets obtained soft-chemically from the exfoliation of layered sodium molybdate, Na0.9Mo2O4. The topotactic phase transformation from the as-grown MoO2 nanosheets to crystalline MoO3-x nanosheets was triggered by a facile calcination at 200 °C in air. Amorphization without significant changes in the sheet structure occurred at 250 °C, yielding a-MoO3-x nanosheets. Among the products, a monolayer film of the a-MoO3-x nanosheets had superior photochromic properties in the visible and infrared ranges via band-gap excitation compared to conventional thin films composed of MoO3-related materials in terms of coloration efficiency, that is, degree of coloration per thickness. The coloration efficiency of the a-MoO3-x nanostructured films fabricated in this study remained unchanged despite an increase in the stacking number of the precursor nanosheets because the amorphous structure inhibited the recombination of electron-hole pairs; moreover, the multilayer structure had interlayer galleries between the nanosheets. Consequently, the thick film comprising layers with a similar a-MoO3-x nanostructure exhibited a remarkable degree of coloration and repeatability of coloration and bleaching cycles, indicating its potential for smart window applications.

Original languageEnglish
JournalACS Applied Nano Materials
Publication statusAccepted/In press - 2021
Externally publishedYes


  • amorphous
  • chromism
  • lamellar structure
  • nanosheets
  • substoichiometric compounds

ASJC Scopus subject areas

  • Materials Science(all)


Dive into the research topics of 'Chromogenic Amorphous MoO3- xNanosheets and Their Nanostructured Films for Smart Window Applications'. Together they form a unique fingerprint.

Cite this