Flexible electrochromic and thermochromic hybrid smart window based on a highly durable ITO/graphene transparent electrode

Sang Jin Lee, Sun Hee Lee, Hyung Won Kang, Sahn Nahm, Bong Hoon Kim, Hyeongkeun Kim, Seung Ho Han

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


A flexible smart window with electrochromic (EC) and thermochromic (TC) properties is fabricated on a highly durable transparent indium-tin oxide (ITO)/graphene/polyethylene terephthalate (PET) electrode. An amorphous WO3 film and crystalline VO2 film are used as the EC and TC material, respectively, in the device. The ITO film deposited via atomic layer deposition acts as a protective layer and suppresses the plasma-induced damage of graphene, which typically occurs during the sputtering process. In this device, the amorphous WO3 film undergoes cathodic electrochromic reactions with high coloration efficiency, while the crystalline VO2 film shows characteristic thermochromic behavior. Thus, the flexible EC–TC hybrid smart window shows the controlled transmission of optical and solar energies according to the surrounding temperature and the applied voltage, allowing selective modulation of the visible and near-infrared light. The flexible EC–TC hybrid device is also very stable under mechanical bending, owing to the robust adhesion of the ITO film on the graphene support and the reduced plasma-induced damage of graphene. The fabricated high-performance, durable ITO/graphene/PET transparent electrode can pave the way for next-generation flexible optoelectronic devices as well as multifunctional flexible smart windows.

Original languageEnglish
Article number129028
JournalChemical Engineering Journal
Publication statusPublished - 2021 Jul 15

Bibliographical note

Funding Information:
This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20182020109430 ), and by Creative Materials Discovery Program and Material Innovation Leading Project through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT ( 2020M3D1A2101136 and 2020M3H4A3081879 ).

Publisher Copyright:
© 2021 Elsevier B.V.


  • Atomic layer deposition
  • Electrochromic materials
  • Flexible smart windows
  • Graphene
  • Thermochromic materials
  • Transparent electrodes

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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