Related Experiment Video
Updated: Jan 28, 2026

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition
Published on: August 29, 2017
Coloration mechanism of electrochromic NaxWO3 thin films
Abstract:
The coloration mechanism of tungsten trioxide (WO3) upon insertion of alkali ions is still under debate after several decades of research. This Letter provides new insights into the reversible insertion and coloration mechanisms of Na+ ions in WO3 thin films sputter-deposited on ITO/glass substrates. A unique model based on a constrained spline approach was developed and applied to draw out ε1+iε2from spectroscopic ellipsometry data from 0.6 to 4.8 eV, whatever the state of the electrochromic active layer, i.e., as-deposited, colored, or bleached. It is shown that electrochemically intercalated sodium-tungsten trioxide, NaxWO3(x=0.1,0.2,0.35), exhibits an absorption band centered at ca. 1.14 eV in ε2 governing the coloration mechanism.
Related Concept Videos
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
Color Vision
Changes in Skin Color: Clinical Perspectives
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
Reaction Mechanisms
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
Mechanical Protein Functions
Mechanism of Conjugation

