Applied IrO2 Buffer Layer as a Great Promoter on Ti-Doping V2O5 Electrode to Enhance Electrochromic Device Properties

Tien-Fu Ko; Po-Wen Chen; Kuan-Ming Li; Hong-Tsu Young

doi:10.3390/ma15155179

Applied IrO₂ Buffer Layer as a Great Promoter on Ti-Doping V₂O₅ Electrode to Enhance Electrochromic Device Properties

Materials (Basel). 2022 Jul 26;15(15):5179. doi: 10.3390/ma15155179.

Authors

Tien-Fu Ko^{1

2}, Po-Wen Chen², Kuan-Ming Li¹, Hong-Tsu Young¹

Affiliations

¹ Department of Mechanical Engineering, National Taiwan University, Taipei City 10617, Taiwan.
² Division of Physics, Institute of Nuclear Energy Research, Taoyuan City 32546, Taiwan.

Abstract

Electrochromic devices (ECDs) are a promising material for smart windows that are capable of transmittance variation. However, ECDs are still too expensive to achieve a wide market reach. Reducing fabrication cost remains a challenge. In this study, we inserted an IrO₂ buffer layer on Ti-doped V₂O₅ (Ti:V₂O₅) as a counter electrode using various Ar/O₂ gas flow ratios (1/2, 1/2.5, 1/3 and 1/3.5) in the fabrication process. The buffered-ECD resulted in a larger cyclic voltammetry (CV) area and the best surface average roughness (Ra = 3.91 nm) to promote electrochromic performance. It was fabricated using the low-cost, fast deposition process of vacuum cathodic arc plasma (CAP). This study investigates the influence of the IrO₂ buffer/Ti:V₂O₅ electrode on ECD electrochemical and optical properties, in terms of color efficiency (CE) and cycle durability. The buffered ECD (glass/ITO/WO₃/liquid electrolyte/IrO₂ buffer/Ti:V₂O₅/ITO/glass) demonstrated excellent optical transmittance modulation; ∆T = 57% (from T_bleaching (67%) to T_coloring (10%)) at 633 nm, which was higher than without the buffer (ITO/WO₃/liquid electrolyte/Ti:V₂O₅/ITO) (∆T = 36%). In addition, by means of an IrO₂ buffer, the ECD exhibited high coloration efficiency of 96.1 cm²/mC and good durability, which decayed by only 2% after 1000 cycles.

Keywords: buffer layer; cathodic arc plasma (CAP); coloration efficiency (CE); electrochromic device (ECD); iridium oxide (IrO2).

Grants and funding

This research was funded by Division of Physics, Institute of Nuclear Energy Research (INER), Taiwan and National Taiwan University under the Excellence Improvement Program for Doctoral Students (grant number 108-2926-I-002-002-MY4), sponsored by Ministry of Science and Technology, Taiwan.