What Causes Color Changes in Electrochromic Thin Films?

[meimanat]

as you know ,Electrochromism is the phenomenon displayed by some materials of reversibly changing color when voltage is applied. i am working on WO3 thin films.i know that redox will happen when voltag is applied.

I am interested to know ,changing in which paramete is caused to thin films of electrochoromic chang its color?

how about photochoromics device?

and whould you mind inform me that why electrochoromic device can control light and heat while photochoromic materials don't control heat gain ,please?

Thanks.

 

[BigJDubs]

The color change in electrochromic materials is caused by a redox reaction that occurs when voltage is applied. The redox reaction causes the material to either become oxidized or reduced, resulting in a change in its optical properties such as color. In contrast, photochromic materials change color due to light exposure. They are not affected by voltage, and therefore do not have the same redox reaction. As a result, photochromic materials do not control heat gain, whereas electrochromic materials can be used to control heat gain by changing their optical properties.