Optical attenuation at the 1,550-nm wavelength in a reflective mode using electrochromic ruthenium complex film

Thin films of a dinuclear ruthenium complex have been prepared on a reflective electrode. The complex is redox-active in the near infrared spectral region. Electrochromic switching between the two oxidation states of the complex film gave 80% optical contrast at the telecommunication wavelength of 1,550 nm, which translates to an intrinsic attenuation of 17.5 dB/μm of the active material. Chronoamperometric study showed excellent stability over extended switching cycles as well as retaining high attenuation with a 5-s stepping time.