Optical absorption in lithiated tungsten oxide thin films : Experiment and theory

• Amorphous tungsten oxide exhibits electrochromism when intercalated with protons, lithium, sodium, and other ions. Thin films of the material were prepared by dc magnetron sputtering and then electrochemically intercalated with lithium. The optical absorption in the wavelength range of 300-2500 nm was measured for a number of lithium concentrations. The optical absorption shows a maximum for lithium/tungsten ratios of 0.3-0.5. The optical spectra can be fitted by a superposition of three Gaussian peaks, representing the three possible electronic transitions between W6+, W5+, and W4+ sites. The variation of the peak strength with lithium concentration is consistent with an extended site-saturation theory.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

amorphous state

electrochromism

infrared spectra

lithium compounds

sputter deposition

thin films

tungsten compounds

ultraviolet spectra

visible spectra

Physics

Fysik

TECHNOLOGY

TEKNIKVETENSKAP

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