Fast Electrochromic Device Based on Single-Walled Carbon Nanotube Thin Films

Significance Statement

A device in which optical properties like reflectance and absorption are controlled by the mean of electric field is known as electrochromic device. Electrochromic materials show the change in their color under application of voltage. In modern days the smart windows utilizing electrochromic phenomena conserve energy and indoor climate.

One of the limitations of the electrochromic devices is their slow response which limits their use in the applications outside of the smart windows field. Researchers from University of California, Riverside found a new way to decrease the response time of the electrochromic devices from tens of minutes to millisecond range. They proposed a nanostructured electrochromic material, thin film of semiconducting single-walled carbon nanotubes, as a new electrochromic media. The charge state of carbon nanotubes and related nanotube thin film transparency is controlled by ionic liquid polarization. The research work is now published in peer-reviewed journal, Nano Letters.

UC Riverside scientists fabricated a nanotube thin film based electro-optical modulator in which the active electrochromic layer is made of a film of semiconducting single-walled carbon nanotubes and the counter-electrode is composed of a film of metallic single-walled carbon nanotubes. With an ionic liquid utilized as an electrolyte, more than 100-fold increase of the operation speed was achieved. The modulation depth up to 6.7 dB has been demonstrated and can be further increased with increasing thickness of carbon nanotube electrochromic layer. The efficiency of the electrochromic device benefits from the high porosity and high surface area of single-walled carbon nanotube network. Such a network forms a three-dimensional electric double layer capacitor which allows fast penetrations of the ionic liquid anions and cations resulting in a fast modulation of the nanotube charge state.

Leading scientist of this project, Dr. Mikhail Itkis (University of California, Riverside), noted that utilization of carbon nanotubes as an active electrochromic media can expand areas of application of electrochromic materials, enhance their performance and functionalities in the field of smart windows, infrared modulators and shutters, and infrared imaging.

About The Author

Mikhail Itkis is an Adjunct Professor in the College of Engineering and Department of Chemistry at the University of California, Riverside. He coauthored more than 150 publications in the field of nanotechnology with overall number of citations exceeding 12,000, and h-index of 54. In 2011, he was recognized by Thomson Reuters as a world top 100 chemist of the past decade based on the high citation impact score for his publications.

His research interests include physics, material science and electronic and photonic applications of low dimensional nanomaterials such as carbon nanotubes, graphene, organic molecular conductors, and charge density waves compounds.

Dr. Itkis earned a B.S. and M.S. degrees in Physics and Engineering from the Moscow Institute of Physics and Technology, Russia, and a Ph.D. in Physics from the Institute of Radio Engineering & Electronics, Russian Academy of Sciences, for his study of quasi-one-dimensional crystals with sliding charge density waves.

Journal Reference

Matthew L. Moser1,3, Guanghui Li2,3, Mingguang Chen2,3, Elena Bekyarova1,3, Mikhail E. Itkis1,2,3, and Robert C. Haddon1,2,3. Fast Electrochromic Device Based on Single-Walled Carbon Nanotube Thin Films, Nano Letters., 2016, 16 (9), pp 5386–5393.

Show Affiliations
  1. Department of Chemistry, University of California, Riverside, California 92521, United States.
  2. Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States.
  3. Center for Nanoscale Science and Engineering, University of California, Riverside, California 92521, United States.

 

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